chore(release): v3.5.1

README.md

@@ -4,9 +4,11 @@
 
 - `mkRepo` for `devShells`, `checks`, `formatter`, and optional `packages.release`
 - structured tool banners driven from package-backed tool specs
-- structured release steps (`writeFile`, `replace`, `run`)
+- structured release steps (`writeFile`, `replace`, `versionMetaSet`, `versionMetaUnset`)
 - a Bun-only Moonrepo + TypeScript + Varlock template in [`template/`](/Users/eric/Projects/repo-lib/template)
 
+Audit and replacement review: [`docs/reviews/2026-03-21-repo-lib-audit.md`](/Users/eric/Projects/repo-lib/docs/reviews/2026-03-21-repo-lib-audit.md)
+
 ## Prerequisites
 
 - [Nix](https://nixos.org/download/) with flakes enabled
@@ -15,7 +17,7 @@
 ## Use the template
 
 ```bash
-nix flake new myapp -t 'git+https://git.dgren.dev/eric/nix-flake-lib?ref=refs/tags/v3.5.0#default' --refresh
+nix flake new myapp -t 'git+https://git.dgren.dev/eric/nix-flake-lib?ref=refs/tags/v3.5.1#default' --refresh
 ```
 
 The generated repo includes:
@@ -32,7 +34,7 @@ The generated repo includes:
 Add this flake input:
 
 ```nix
-inputs.repo-lib.url = "git+https://git.dgren.dev/eric/nix-flake-lib?ref=refs/tags/v3.5.0";
+inputs.repo-lib.url = "git+https://git.dgren.dev/eric/nix-flake-lib?ref=refs/tags/v3.5.1";
 inputs.repo-lib.inputs.nixpkgs.follows = "nixpkgs";
 ```
 
@@ -154,10 +156,9 @@ config.release = {
       };
     }
     {
-      run = {
-        script = ''
-          echo "Released $FULL_TAG"
-        '';
+      versionMetaSet = {
+        key = "desktop_binary_version_max";
+        value = "$FULL_VERSION";
       };
     }
   ];
@@ -168,16 +169,30 @@ The generated `release` command still supports:
 
 ```bash
 release
+release select
+release --dry-run patch
 release patch
+release patch --commit
+release patch --commit --tag
+release patch --commit --tag --push
 release beta
 release minor beta
 release stable
 release set 1.2.3
 ```
 
+By default, `release` updates repo files, runs structured release steps, executes `postVersion`, and runs `nix fmt`, but it does not commit, tag, or push unless you opt in with flags.
+
+- `--commit` stages all changes and creates `chore(release): <tag>`
+- `--tag` creates the Git tag after commit
+- `--push` pushes the current branch and, when tagging is enabled, pushes tags too
+- `--dry-run` resolves and prints the plan without mutating the repo
+
+When `release` runs with no args in an interactive terminal, it opens a Bubble Tea picker so you can preview the exact command, flags, and resolved next version before executing it. Use `release select` to force that picker explicitly.
+
 ## Low-level APIs
 
-`mkDevShell` and `mkRelease` remain available for repos that want lower-level control or a migration path from the older library shape.
+`mkRelease` remains available for repos that want lower-level control over release automation.
 
 ## Common command
 

VERSION

@@ -1,4 +1,3 @@
-3.5.0
+3.5.1
 stable
 0
-

docs/reviews/2026-03-21-repo-lib-audit.md

@@ -0,0 +1,292 @@
+# Repo-Lib Audit
+
+Date: 2026-03-21
+
+## Direct Answers
+
+### 1. Does it work today?
+
+Partially.
+
+- `nix flake show --all-systems` succeeds from the repo root.
+- Before this audit, `nix flake check` failed because the old shell-based release test harness relied on a brittle regex over `nix derivation show` internals instead of asserting against stable JSON structure.
+- `mkRepo`, the template flake, the dev shell, and the formatter/check outputs all evaluate. The primary failure was test-harness fragility, not a clear functional break in the library itself.
+- The release path still carries real operational risk because [`packages/release/release.sh`](../../../packages/release/release.sh) combines mutation, formatting, commit, tag, and push in one command and uses destructive rollback.
+
+### 2. Is the code organization maintainable?
+
+Not in its current shape.
+
+- [`packages/repo-lib/lib.nix`](../../../packages/repo-lib/lib.nix) is a single 879-line module that owns unrelated concerns:
+  - tool schema normalization
+  - hook/check config synthesis
+  - shell banner generation
+  - release step normalization
+  - public API assembly
+- [`packages/repo-lib/shell-hook.sh`](../../../packages/repo-lib/shell-hook.sh) is not just presentation. It contains tool probing, parsing, error handling, and shell-failure behavior.
+- `mkDevShell` and `mkRepo` overlap conceptually and preserve legacy paths that make the main implementation harder to reason about.
+
+### 3. Is the public API readable and usable for consumers?
+
+Usable, but underspecified and harder to learn than the README suggests.
+
+- [`README.md`](../../../README.md) presents `mkRepo` as a compact abstraction, but the real behavior is distributed across `lib.nix`, `shell-hook.sh`, generated Lefthook config, and the release script.
+- The boundaries between `config`, `perSystem`, `checks`, `lefthook`, `shell`, `tools`, and `release` are not obvious from the docs alone.
+- Raw `config.lefthook` / `perSystem.lefthook` passthrough is effectively required for advanced use, which means the higher-level `checks` abstraction is incomplete.
+
+### 4. Which parts should be kept, split, or replaced?
+
+Keep:
+
+- the high-level `mkRepo` consumer entrypoint, if compatibility matters
+- the template
+- the structured release-step idea
+
+Split:
+
+- release tooling from repo shell/hook wiring
+- shell banner rendering from shell/package assembly
+- hook/check generation from the rest of `mkRepo`
+
+Replace:
+
+- custom flake output composition with `flake-parts`
+- custom hook glue with `lefthook.nix`
+- keep `treefmt-nix` as the formatting layer rather than wrapping it deeper
+
+### 5. What is the lowest-complexity target architecture?
+
+Option A: keep `repo-lib.lib.mkRepo` as a thin compatibility wrapper, but rebase its internals on established components:
+
+- `flake-parts` for flake structure and `perSystem`
+- `treefmt-nix` for formatting
+- `lefthook.nix` for hooks
+- a separate `mkRelease` package for release automation, with explicit opt-ins for commit/tag/push
+
+That preserves migration cost for consumers while removing most of the custom orchestration burden from this repo.
+
+## Correctness Findings
+
+### High: self-checks were failing because the test harness depended on unstable derivation internals
+
+Files:
+
+- the removed shell-based release test harness
+
+Details:
+
+- The repo did not pass `nix flake check` on the host system before this audit because the tests around `lefthook-check` assumed `nix derivation show` would expose `"/nix/store/...-lefthook.yml.drv"` as a quoted string.
+- Current Nix emits input derivations in a different JSON shape, so the regex broke even though the underlying derivation still existed.
+- This is a release blocker because the repo’s own baseline was red.
+
+Assessment:
+
+- Fixed in this audit by replacing the ad hoc scrape with a helper that locates the relevant input derivation from the JSON more defensibly.
+
+### High: release rollback is destructive
+
+Files:
+
+- [`packages/release/release.sh`](../../../packages/release/release.sh)
+
+Details:
+
+- `revert_on_failure` runs `git reset --hard "$START_HEAD"` after any trapped error.
+- That will discard all working tree changes created during the release flow, including user-visible file changes that might be useful for debugging or manual recovery.
+
+Assessment:
+
+- This is too aggressive for a library-provided command.
+- Rollback should be opt-in, staged to a temp branch/worktree, or replaced with a safer failure mode that leaves artifacts visible.
+
+### Medium: release performs too many side effects in one irreversible flow
+
+Files:
+
+- [`packages/release/release.sh`](../../../packages/release/release.sh)
+
+Details:
+
+- The default flow updates version state, runs release steps, formats, stages, commits, tags, and pushes.
+- There is no dry-run mode.
+- There is no `--no-push`, `--no-tag`, or `--no-commit` mode.
+- The command is framed as a package generated by the library, so consumers inherit a strong opinionated workflow whether they want it or not.
+
+Assessment:
+
+- Release should be separated from repo shell wiring and broken into explicit phases or flags.
+
+## Organization And Readability Findings
+
+### High: `lib.nix` is a monolith
+
+Files:
+
+- [`packages/repo-lib/lib.nix`](../../../packages/repo-lib/lib.nix)
+
+Details:
+
+- One file owns normalization helpers, shell assembly, banner formatting inputs, Lefthook synthesis, release templating, compatibility APIs, and top-level outputs.
+- The public API is therefore not separable from its implementation detail.
+
+Assessment:
+
+- This is the main maintainability problem in the repo.
+- Even if behavior is mostly correct, the cost of safely changing it is too high.
+
+### Medium: shell UX logic is coupled to operational behavior
+
+Files:
+
+- [`packages/repo-lib/shell-hook.sh`](../../../packages/repo-lib/shell-hook.sh)
+- [`packages/repo-lib/lib.nix`](../../../packages/repo-lib/lib.nix)
+
+Details:
+
+- Tool banners do more than render text. They probe commands, parse versions, print failures, and may exit the shell startup for required tools.
+- That behavior is not obvious from the README example and is spread across generated shell script fragments.
+
+Assessment:
+
+- The banner feature is nice, but it is expensive in complexity and debugging surface relative to the value it adds.
+- If retained, it should be optional and isolated behind a smaller interface.
+
+### Medium: legacy compatibility paths dominate the core implementation
+
+Files:
+
+- [`packages/repo-lib/lib.nix`](../../../packages/repo-lib/lib.nix)
+
+Details:
+
+- `mkDevShell` uses legacy tool normalization and its own feature toggles.
+- `mkRepo` carries a newer strict tool shape.
+- Both flows feed the same shell-artifact builder, which means the common implementation has to keep both mental models alive.
+
+Assessment:
+
+- Deprecate `mkDevShell` once a thin `mkRepo` wrapper exists over standard components.
+
+## Public API And Usability Findings
+
+### High: README underspecifies the real API
+
+Files:
+
+- [`README.md`](../../../README.md)
+
+Details:
+
+- The README explains the happy-path shape of `mkRepo`, but not the actual behavioral contract.
+- It does not provide a reference for:
+  - tool spec fields
+  - shell banner behavior
+  - exact merge order between `config` and `perSystem`
+  - what the `checks` abstraction cannot express
+  - what `release` is allowed to mutate by default
+
+Assessment:
+
+- Consumers can start quickly, but they cannot predict behavior well without reading the implementation.
+
+### Medium: abstraction boundaries are blurry
+
+Files:
+
+- [`README.md`](../../../README.md)
+- [`template/flake.nix`](../../../template/flake.nix)
+- [`packages/repo-lib/lib.nix`](../../../packages/repo-lib/lib.nix)
+
+Details:
+
+- `checks` looks like the high-level hook API, but advanced usage requires raw Lefthook passthrough.
+- `shell.bootstrap` is documented as the purity escape hatch, but the template uses it for tool bootstrapping and operational setup.
+- `release` is presented as optional packaging, but it is operational automation with repo mutation and remote side effects.
+
+Assessment:
+
+- These concepts should be separate modules with narrower contracts.
+
+## Replacement Options
+
+### Option A: thin compatibility layer
+
+Keep `repo-lib.lib.mkRepo`, but make it a wrapper over standard components.
+
+Use:
+
+- `flake-parts` for top-level flake assembly and `perSystem`
+- `treefmt-nix` for formatting
+- `lefthook.nix` for Git hooks
+- a standalone `mkRelease` output for release automation
+
+Pros:
+
+- lower migration cost
+- preserves existing entrypoint
+- reduces bespoke glue
+
+Cons:
+
+- some compatibility debt remains
+- requires a staged migration plan
+
+### Option B: full replacement
+
+Stop positioning this as a general-purpose Nix library and keep only:
+
+- the template
+- any repo-specific release helper
+- migration docs to standard tools
+
+Pros:
+
+- lowest long-term maintenance burden
+- clearest product boundary
+
+Cons:
+
+- highest consumer migration cost
+- discards the existing `mkRepo` API
+
+## Final Recommendation
+
+Choose **Option A**.
+
+Rationale:
+
+- `mkRepo` has enough consumer value to keep as a compatibility surface.
+- Most of the complexity is not unique value. It is custom orchestration around capabilities already provided by better-maintained ecosystem tools.
+- The release flow should be split out regardless of which option is chosen.
+
+Concrete target:
+
+1. Rebase flake structure on `flake-parts`.
+2. Replace custom hook synthesis with `lefthook.nix`.
+3. Keep `treefmt-nix` directly exposed instead of deeply wrapped.
+4. Make shell banners optional or move them behind a very small isolated module.
+5. Move release automation into a separate package with explicit side-effect flags.
+6. Mark `mkDevShell` deprecated once `mkRepo` is stable on the new internals.
+
+## Migration Cost And Compatibility Notes
+
+- A thin compatibility wrapper keeps consumer migration reasonable.
+- The biggest compatibility risk is release behavior, because some consumers may depend on the current commit/tag/push flow.
+- Introduce safer release behavior behind new flags first, then deprecate the old all-in-one default.
+- Keep template output working during the transition; it is currently the clearest example of intended usage.
+
+## Required Validation For Follow-Up Work
+
+- `nix flake show --all-systems`
+- `nix flake check`
+- minimal consumer repo using `mkRepo`
+- template repo evaluation
+- release smoke test in a temporary git repo
+- hook assertions that do not depend on private derivation naming/layout
+
+## Sources
+
+- `flake-parts`: https://flake.parts/
+- `treefmt-nix`: https://github.com/numtide/treefmt-nix
+- `lefthook.nix`: https://github.com/cachix/lefthook.nix
+- `devenv`: https://github.com/cachix/devenv

docs/superpowers/plans/2026-03-16-typescript-monorepo-template.md

@@ -1,99 +0,0 @@
-# TypeScript Monorepo Template Implementation Plan
-
-> **For agentic workers:** REQUIRED: Use superpowers:subagent-driven-development (if subagents available) or superpowers:executing-plans to implement this plan. Steps use checkbox (`- [ ]`) syntax for tracking.
-
-**Goal:** Replace the minimal starter template with a Bun-only Moonrepo + TypeScript + Varlock monorepo template exposed through the existing flake template.
-
-**Architecture:** Expand `template/` into a complete repository skeleton while keeping `repo-lib.lib.mkRepo` as the integration point. Adapt the strict TypeScript config layout and Varlock command pattern from `../moon`, and update release tests so they evaluate the full template contents.
-
-**Tech Stack:** Nix flakes, repo-lib, Bun, Moonrepo, Varlock, TypeScript
-
----
-
-## Chunk 1: Documentation Baseline
-
-### Task 1: Update public template docs
-
-**Files:**
-- Modify: `README.md`
-
-- [ ] **Step 1: Write the failing expectation mentally against current docs**
-
-Current docs describe only a minimal starter template and do not mention Bun, Moonrepo, or Varlock.
-
-- [ ] **Step 2: Update the README to describe the new template**
-
-Document the generated workspace shape and first-run commands.
-
-- [ ] **Step 3: Verify the README content is consistent with the template files**
-
-Check all commands and filenames against the final template layout.
-
-## Chunk 2: Template Skeleton
-
-### Task 2: Replace the minimal template with a real monorepo skeleton
-
-**Files:**
-- Modify: `template/flake.nix`
-- Create: `template/package.json`
-- Create: `template/bunfig.toml`
-- Create: `template/moon.yml`
-- Create: `template/tsconfig.json`
-- Create: `template/tsconfig.options.json`
-- Create: `template/tsconfig/browser.json`
-- Create: `template/tsconfig/bun.json`
-- Create: `template/tsconfig/package.json`
-- Create: `template/tsconfig/runtime.json`
-- Create: `template/.env.schema`
-- Modify: `template/.gitignore`
-- Create: `template/README.md`
-- Create: `template/apps/.gitkeep`
-- Create: `template/packages/.gitkeep`
-
-- [ ] **Step 1: Add or update template files**
-
-Use `../moon` as the source for Moonrepo, Varlock, and TypeScript patterns, removing product-specific details.
-
-- [ ] **Step 2: Verify the template tree is coherent**
-
-Check that all referenced files exist and that scripts reference only template-safe commands.
-
-## Chunk 3: Test Coverage
-
-### Task 3: Update release tests for the full template
-
-**Files:**
-- Modify: `tests/release.sh`
-
-- [ ] **Step 1: Add a failing test expectation**
-
-The current template fixture copies only `template/flake.nix`, which is insufficient for the new template layout.
-
-- [ ] **Step 2: Update fixture creation to copy the full template**
-
-Rewrite template URL references in copied files as needed for local test evaluation.
-
-- [ ] **Step 3: Verify the existing template evaluation case now uses the real skeleton**
-
-Confirm `nix flake show` runs against the expanded template fixture.
-
-## Chunk 4: Verification
-
-### Task 4: Run template verification
-
-**Files:**
-- Verify: `README.md`
-- Verify: `template/**/*`
-- Verify: `tests/release.sh`
-
-- [ ] **Step 1: Run the release test suite**
-
-Run: `nix develop -c bash tests/release.sh`
-
-- [ ] **Step 2: Inspect the template file tree**
-
-Run: `find template -maxdepth 3 -type f | sort`
-
-- [ ] **Step 3: Verify the README examples still match the tagged template release pattern**
-
-Check that versioned `repo-lib` URLs remain in the documented commands and release replacements.

docs/superpowers/specs/2026-03-16-typescript-monorepo-template-design.md

@@ -1,88 +0,0 @@
-# TypeScript Monorepo Template Design
-
-## Goal
-
-Add a new default template to this repository that generates a Bun-only TypeScript monorepo using Moonrepo, Varlock, and the shared TypeScript configuration pattern from `../moon`.
-
-## Scope
-
-The generated template should include:
-
-- a Nix flake wired through `repo-lib.lib.mkRepo`
-- Bun-only JavaScript tooling
-- Moonrepo root configuration
-- strict shared TypeScript configs adapted from `../moon`
-- Varlock enabled from day one
-- a committed `.env.schema`
-- empty `apps/` and `packages/` directories
-- minimal documentation for first-run setup
-
-The template should not include:
-
-- demo apps or packages
-- product-specific environment variables or OpenBao paths from `../moon`
-- Node or pnpm support
-
-## Architecture
-
-The existing `template/` directory remains the exported flake template. Instead of containing only a starter `flake.nix`, it will become a complete repository skeleton.
-
-The generated repository will keep the current `repo-lib` integration pattern:
-
-- `template/flake.nix` calls `repo-lib.lib.mkRepo`
-- the shell provisions Bun, Moonrepo CLI, Varlock, and supporting tooling
-- repo checks remain driven through `mkRepo` and Lefthook
-
-Moonrepo and Varlock will be configured at the workspace root. The template will expose root tasks and scripts that work even before any projects are added.
-
-## Template Contents
-
-The template should contain:
-
-- `flake.nix`
-- `package.json`
-- `bunfig.toml`
-- `moon.yml`
-- `tsconfig.json`
-- `tsconfig.options.json`
-- `tsconfig/browser.json`
-- `tsconfig/bun.json`
-- `tsconfig/package.json`
-- `tsconfig/runtime.json`
-- `.env.schema`
-- `.gitignore`
-- `README.md`
-- `apps/.gitkeep`
-- `packages/.gitkeep`
-
-It may also keep generic repo support files already useful in templates, such as `.envrc`, `.gitlint`, `.gitleaks.toml`, `.vscode/settings.json`, and `flake.lock`, as long as they remain template-safe.
-
-## Data And Command Flow
-
-On first use:
-
-1. the user creates a repo from the flake template
-2. the shell provides Bun, Moonrepo, Varlock, and release support
-3. `bun install` installs `@moonrepo/cli`, `varlock`, and TypeScript-related dependencies
-4. entering the repo loads `varlock/auto-load`
-5. root commands like `bun run env:check`, `bun run env:scan`, and `moon run :typecheck` work without any sample projects
-
-## Varlock Design
-
-The template will include a minimal `.env.schema` with:
-
-- one canonical environment selector
-- safe local defaults where practical
-- placeholders for OpenBao-backed secrets using generic template paths
-
-Root scripts in `package.json` will follow the `../moon` pattern for `env:check` and `env:scan`, including `BAO_*` and `OPENBAO_*` compatibility exports. The template will not encode any product-specific namespace names.
-
-## Testing
-
-Existing release tests must continue to validate the exported template. The template fixture helper in `tests/release.sh` will need to copy the full template directory, not only `template/flake.nix`, so `nix flake show` exercises the real generated repository structure.
-
-## Risks
-
-- Moonrepo root task behavior must remain valid with no projects present.
-- Template-safe Varlock defaults must avoid broken first-run behavior while still demonstrating the intended pattern.
-- The release test harness must not accidentally preserve upstream URLs inside the copied template.

flake.lock

@@ -1,5 +1,23 @@
 {
   "nodes": {
+    "flake-parts": {
+      "inputs": {
+        "nixpkgs-lib": "nixpkgs-lib"
+      },
+      "locked": {
+        "lastModified": 1772408722,
+        "narHash": "sha256-rHuJtdcOjK7rAHpHphUb1iCvgkU3GpfvicLMwwnfMT0=",
+        "owner": "hercules-ci",
+        "repo": "flake-parts",
+        "rev": "f20dc5d9b8027381c474144ecabc9034d6a839a3",
+        "type": "github"
+      },
+      "original": {
+        "owner": "hercules-ci",
+        "repo": "flake-parts",
+        "type": "github"
+      }
+    },
     "lefthook-nix": {
       "inputs": {
         "nixpkgs": [
@@ -36,6 +54,21 @@
         "type": "github"
       }
     },
+    "nixpkgs-lib": {
+      "locked": {
+        "lastModified": 1772328832,
+        "narHash": "sha256-e+/T/pmEkLP6BHhYjx6GmwP5ivonQQn0bJdH9YrRB+Q=",
+        "owner": "nix-community",
+        "repo": "nixpkgs.lib",
+        "rev": "c185c7a5e5dd8f9add5b2f8ebeff00888b070742",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nix-community",
+        "repo": "nixpkgs.lib",
+        "type": "github"
+      }
+    },
     "nixpkgs_2": {
       "locked": {
         "lastModified": 1770107345,
@@ -54,6 +87,7 @@
     },
     "root": {
       "inputs": {
+        "flake-parts": "flake-parts",
         "lefthook-nix": "lefthook-nix",
         "nixpkgs": "nixpkgs",
         "treefmt-nix": "treefmt-nix"

flake.nix

@@ -3,6 +3,7 @@
   description = "Pure-first repo development platform for Nix flakes";
 
   inputs = {
+    flake-parts.url = "github:hercules-ci/flake-parts";
     nixpkgs.url = "github:nixos/nixpkgs?ref=nixos-unstable";
     lefthook-nix.url = "github:sudosubin/lefthook.nix";
     lefthook-nix.inputs.nixpkgs.follows = "nixpkgs";
@@ -12,6 +13,7 @@
   outputs =
     {
       self,
+      flake-parts,
       nixpkgs,
       treefmt-nix,
       lefthook-nix,
@@ -20,7 +22,7 @@
     let
       lib = nixpkgs.lib;
       repoLib = import ./packages/repo-lib/lib.nix {
-        inherit nixpkgs treefmt-nix;
+        inherit flake-parts nixpkgs treefmt-nix;
         lefthookNix = lefthook-nix;
         releaseScriptPath = ./packages/release/release.sh;
         shellHookTemplatePath = ./packages/repo-lib/shell-hook.sh;
@@ -94,20 +96,16 @@
             pkgs.runCommand "release-tests"
               {
                 nativeBuildInputs = with pkgs; [
-                  bash
+                  go
                   git
-                  nix
-                  gnused
-                  coreutils
-                  gnugrep
-                  perl
                 ];
               }
               ''
-                export REPO_LIB_ROOT=${./.}
-                export NIXPKGS_FLAKE_PATH=${nixpkgs}
-                export HOME="$TMPDIR"
-                ${pkgs.bash}/bin/bash ${./tests/release.sh}
+                export HOME="$PWD/.home"
+                export GOCACHE="$PWD/.go-cache"
+                mkdir -p "$GOCACHE" "$HOME"
+                cd ${./packages/release}
+                go test ./...
                 touch "$out"
               '';
         }

packages/release/.gitignore

@@ -0,0 +1 @@
+vendor/

packages/release/cmd/release/main.go

@@ -0,0 +1,135 @@
+package main
+
+import (
+	"fmt"
+	"os"
+	"strings"
+
+	release "repo-lib/packages/release/internal/release"
+)
+
+func main() {
+	if err := run(os.Args[1:]); err != nil {
+		fmt.Fprintln(os.Stderr, "Error:", err)
+		os.Exit(1)
+	}
+}
+
+func run(args []string) error {
+	if len(args) > 0 && args[0] == "version-meta" {
+		return runVersionMeta(args[1:])
+	}
+
+	releaseArgs, execution, selectMode, err := parseReleaseCLIArgs(args)
+	if err != nil {
+		return err
+	}
+
+	config := release.Config{
+		RootDir:          os.Getenv("REPO_LIB_RELEASE_ROOT_DIR"),
+		AllowedChannels:  splitEnvList("REPO_LIB_RELEASE_CHANNELS"),
+		ReleaseStepsJSON: os.Getenv("REPO_LIB_RELEASE_STEPS_JSON"),
+		PostVersion:      os.Getenv("REPO_LIB_RELEASE_POST_VERSION"),
+		Execution:        execution,
+		Env:              os.Environ(),
+		Stdout:           os.Stdout,
+		Stderr:           os.Stderr,
+	}
+
+	if shouldRunInteractiveSelector(releaseArgs, selectMode) {
+		if !release.IsInteractiveTerminal(os.Stdin, os.Stdout) {
+			return fmt.Errorf("interactive release selector requires a terminal")
+		}
+		selectedArgs, confirmed, err := release.SelectCommand(config)
+		if err != nil {
+			return err
+		}
+		if !confirmed {
+			return nil
+		}
+		releaseArgs = selectedArgs
+	}
+
+	r := &release.Runner{Config: config}
+	return r.Run(releaseArgs)
+}
+
+func shouldRunInteractiveSelector(args []string, selectMode bool) bool {
+	if selectMode {
+		return true
+	}
+	if len(args) == 0 {
+		return release.IsInteractiveTerminal(os.Stdin, os.Stdout)
+	}
+	return false
+}
+
+func parseReleaseCLIArgs(args []string) ([]string, release.ExecutionOptions, bool, error) {
+	var releaseArgs []string
+	execution := release.ExecutionOptions{}
+	selectMode := false
+
+	for _, arg := range args {
+		switch arg {
+		case "select":
+			selectMode = true
+		case "--dry-run":
+			execution.DryRun = true
+		case "--commit":
+			execution.Commit = true
+		case "--tag":
+			execution.Tag = true
+		case "--push":
+			execution.Push = true
+		default:
+			if strings.HasPrefix(arg, "--") {
+				return nil, release.ExecutionOptions{}, false, fmt.Errorf("unknown flag %q", arg)
+			}
+			releaseArgs = append(releaseArgs, arg)
+		}
+	}
+
+	if selectMode && len(releaseArgs) > 0 {
+		return nil, release.ExecutionOptions{}, false, fmt.Errorf("select does not take a release argument")
+	}
+	return releaseArgs, execution.Normalize(), selectMode, nil
+}
+
+func runVersionMeta(args []string) error {
+	if len(args) < 2 {
+		return fmt.Errorf("version-meta requires an action and key")
+	}
+	rootDir := os.Getenv("ROOT_DIR")
+	if rootDir == "" {
+		return fmt.Errorf("ROOT_DIR is required")
+	}
+	versionPath := rootDir + "/VERSION"
+	file, err := release.ReadVersionFile(versionPath)
+	if err != nil {
+		return err
+	}
+
+	switch args[0] {
+	case "set":
+		if len(args) != 3 {
+			return fmt.Errorf("version-meta set requires key and value")
+		}
+		file.Metadata.Set(args[1], args[2])
+	case "unset":
+		if len(args) != 2 {
+			return fmt.Errorf("version-meta unset requires key")
+		}
+		file.Metadata.Unset(args[1])
+	default:
+		return fmt.Errorf("unknown version-meta action %q", args[0])
+	}
+	return file.Write(versionPath)
+}
+
+func splitEnvList(name string) []string {
+	raw := strings.Fields(os.Getenv(name))
+	if len(raw) == 0 {
+		return nil
+	}
+	return raw
+}

packages/release/go.mod

@@ -0,0 +1,29 @@
+module repo-lib/packages/release
+
+go 1.25.0
+
+require (
+	github.com/charmbracelet/bubbletea v1.3.10
+	golang.org/x/term v0.41.0
+)
+
+require (
+	github.com/aymanbagabas/go-osc52/v2 v2.0.1 // indirect
+	github.com/charmbracelet/colorprofile v0.2.3-0.20250311203215-f60798e515dc // indirect
+	github.com/charmbracelet/lipgloss v1.1.0 // indirect
+	github.com/charmbracelet/x/ansi v0.10.1 // indirect
+	github.com/charmbracelet/x/cellbuf v0.0.13-0.20250311204145-2c3ea96c31dd // indirect
+	github.com/charmbracelet/x/term v0.2.1 // indirect
+	github.com/erikgeiser/coninput v0.0.0-20211004153227-1c3628e74d0f // indirect
+	github.com/lucasb-eyer/go-colorful v1.2.0 // indirect
+	github.com/mattn/go-isatty v0.0.20 // indirect
+	github.com/mattn/go-localereader v0.0.1 // indirect
+	github.com/mattn/go-runewidth v0.0.16 // indirect
+	github.com/muesli/ansi v0.0.0-20230316100256-276c6243b2f6 // indirect
+	github.com/muesli/cancelreader v0.2.2 // indirect
+	github.com/muesli/termenv v0.16.0 // indirect
+	github.com/rivo/uniseg v0.4.7 // indirect
+	github.com/xo/terminfo v0.0.0-20220910002029-abceb7e1c41e // indirect
+	golang.org/x/sys v0.42.0 // indirect
+	golang.org/x/text v0.3.8 // indirect
+)

packages/release/go.sum

@@ -0,0 +1,45 @@
+github.com/aymanbagabas/go-osc52/v2 v2.0.1 h1:HwpRHbFMcZLEVr42D4p7XBqjyuxQH5SMiErDT4WkJ2k=
+github.com/aymanbagabas/go-osc52/v2 v2.0.1/go.mod h1:uYgXzlJ7ZpABp8OJ+exZzJJhRNQ2ASbcXHWsFqH8hp8=
+github.com/charmbracelet/bubbletea v1.3.10 h1:otUDHWMMzQSB0Pkc87rm691KZ3SWa4KUlvF9nRvCICw=
+github.com/charmbracelet/bubbletea v1.3.10/go.mod h1:ORQfo0fk8U+po9VaNvnV95UPWA1BitP1E0N6xJPlHr4=
+github.com/charmbracelet/colorprofile v0.2.3-0.20250311203215-f60798e515dc h1:4pZI35227imm7yK2bGPcfpFEmuY1gc2YSTShr4iJBfs=
+github.com/charmbracelet/colorprofile v0.2.3-0.20250311203215-f60798e515dc/go.mod h1:X4/0JoqgTIPSFcRA/P6INZzIuyqdFY5rm8tb41s9okk=
+github.com/charmbracelet/lipgloss v1.1.0 h1:vYXsiLHVkK7fp74RkV7b2kq9+zDLoEU4MZoFqR/noCY=
+github.com/charmbracelet/lipgloss v1.1.0/go.mod h1:/6Q8FR2o+kj8rz4Dq0zQc3vYf7X+B0binUUBwA0aL30=
+github.com/charmbracelet/x/ansi v0.10.1 h1:rL3Koar5XvX0pHGfovN03f5cxLbCF2YvLeyz7D2jVDQ=
+github.com/charmbracelet/x/ansi v0.10.1/go.mod h1:3RQDQ6lDnROptfpWuUVIUG64bD2g2BgntdxH0Ya5TeE=
+github.com/charmbracelet/x/cellbuf v0.0.13-0.20250311204145-2c3ea96c31dd h1:vy0GVL4jeHEwG5YOXDmi86oYw2yuYUGqz6a8sLwg0X8=
+github.com/charmbracelet/x/cellbuf v0.0.13-0.20250311204145-2c3ea96c31dd/go.mod h1:xe0nKWGd3eJgtqZRaN9RjMtK7xUYchjzPr7q6kcvCCs=
+github.com/charmbracelet/x/term v0.2.1 h1:AQeHeLZ1OqSXhrAWpYUtZyX1T3zVxfpZuEQMIQaGIAQ=
+github.com/charmbracelet/x/term v0.2.1/go.mod h1:oQ4enTYFV7QN4m0i9mzHrViD7TQKvNEEkHUMCmsxdUg=
+github.com/erikgeiser/coninput v0.0.0-20211004153227-1c3628e74d0f h1:Y/CXytFA4m6baUTXGLOoWe4PQhGxaX0KpnayAqC48p4=
+github.com/erikgeiser/coninput v0.0.0-20211004153227-1c3628e74d0f/go.mod h1:vw97MGsxSvLiUE2X8qFplwetxpGLQrlU1Q9AUEIzCaM=
+github.com/lucasb-eyer/go-colorful v1.2.0 h1:1nnpGOrhyZZuNyfu1QjKiUICQ74+3FNCN69Aj6K7nkY=
+github.com/lucasb-eyer/go-colorful v1.2.0/go.mod h1:R4dSotOR9KMtayYi1e77YzuveK+i7ruzyGqttikkLy0=
+github.com/mattn/go-isatty v0.0.20 h1:xfD0iDuEKnDkl03q4limB+vH+GxLEtL/jb4xVJSWWEY=
+github.com/mattn/go-isatty v0.0.20/go.mod h1:W+V8PltTTMOvKvAeJH7IuucS94S2C6jfK/D7dTCTo3Y=
+github.com/mattn/go-localereader v0.0.1 h1:ygSAOl7ZXTx4RdPYinUpg6W99U8jWvWi9Ye2JC/oIi4=
+github.com/mattn/go-localereader v0.0.1/go.mod h1:8fBrzywKY7BI3czFoHkuzRoWE9C+EiG4R1k4Cjx5p88=
+github.com/mattn/go-runewidth v0.0.16 h1:E5ScNMtiwvlvB5paMFdw9p4kSQzbXFikJ5SQO6TULQc=
+github.com/mattn/go-runewidth v0.0.16/go.mod h1:Jdepj2loyihRzMpdS35Xk/zdY8IAYHsh153qUoGf23w=
+github.com/muesli/ansi v0.0.0-20230316100256-276c6243b2f6 h1:ZK8zHtRHOkbHy6Mmr5D264iyp3TiX5OmNcI5cIARiQI=
+github.com/muesli/ansi v0.0.0-20230316100256-276c6243b2f6/go.mod h1:CJlz5H+gyd6CUWT45Oy4q24RdLyn7Md9Vj2/ldJBSIo=
+github.com/muesli/cancelreader v0.2.2 h1:3I4Kt4BQjOR54NavqnDogx/MIoWBFa0StPA8ELUXHmA=
+github.com/muesli/cancelreader v0.2.2/go.mod h1:3XuTXfFS2VjM+HTLZY9Ak0l6eUKfijIfMUZ4EgX0QYo=
+github.com/muesli/termenv v0.16.0 h1:S5AlUN9dENB57rsbnkPyfdGuWIlkmzJjbFf0Tf5FWUc=
+github.com/muesli/termenv v0.16.0/go.mod h1:ZRfOIKPFDYQoDFF4Olj7/QJbW60Ol/kL1pU3VfY/Cnk=
+github.com/rivo/uniseg v0.2.0/go.mod h1:J6wj4VEh+S6ZtnVlnTBMWIodfgj8LQOQFoIToxlJtxc=
+github.com/rivo/uniseg v0.4.7 h1:WUdvkW8uEhrYfLC4ZzdpI2ztxP1I582+49Oc5Mq64VQ=
+github.com/rivo/uniseg v0.4.7/go.mod h1:FN3SvrM+Zdj16jyLfmOkMNblXMcoc8DfTHruCPUcx88=
+github.com/xo/terminfo v0.0.0-20220910002029-abceb7e1c41e h1:JVG44RsyaB9T2KIHavMF/ppJZNG9ZpyihvCd0w101no=
+github.com/xo/terminfo v0.0.0-20220910002029-abceb7e1c41e/go.mod h1:RbqR21r5mrJuqunuUZ/Dhy/avygyECGrLceyNeo4LiM=
+golang.org/x/exp v0.0.0-20220909182711-5c715a9e8561 h1:MDc5xs78ZrZr3HMQugiXOAkSZtfTpbJLDr/lwfgO53E=
+golang.org/x/exp v0.0.0-20220909182711-5c715a9e8561/go.mod h1:cyybsKvd6eL0RnXn6p/Grxp8F5bW7iYuBgsNCOHpMYE=
+golang.org/x/sys v0.0.0-20210809222454-d867a43fc93e/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.6.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.42.0 h1:omrd2nAlyT5ESRdCLYdm3+fMfNFE/+Rf4bDIQImRJeo=
+golang.org/x/sys v0.42.0/go.mod h1:4GL1E5IUh+htKOUEOaiffhrAeqysfVGipDYzABqnCmw=
+golang.org/x/term v0.41.0 h1:QCgPso/Q3RTJx2Th4bDLqML4W6iJiaXFq2/ftQF13YU=
+golang.org/x/term v0.41.0/go.mod h1:3pfBgksrReYfZ5lvYM0kSO0LIkAl4Yl2bXOkKP7Ec2A=
+golang.org/x/text v0.3.8 h1:nAL+RVCQ9uMn3vJZbV+MRnydTJFPf8qqY42YiA6MrqY=
+golang.org/x/text v0.3.8/go.mod h1:E6s5w1FMmriuDzIBO73fBruAKo1PCIq6d2Q6DHfQ8WQ=

packages/release/internal/release/exec.go

@@ -0,0 +1,91 @@
+package release
+
+import (
+	"bytes"
+	"errors"
+	"fmt"
+	"io"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"strings"
+)
+
+func requireCleanGit(rootDir string) error {
+	if _, err := runCommand(rootDir, nil, io.Discard, io.Discard, "git", "diff", "--quiet"); err != nil {
+		return errors.New("git working tree is not clean. Commit or stash changes first")
+	}
+	if _, err := runCommand(rootDir, nil, io.Discard, io.Discard, "git", "diff", "--cached", "--quiet"); err != nil {
+		return errors.New("git working tree is not clean. Commit or stash changes first")
+	}
+	return nil
+}
+
+func gitOutput(dir string, args ...string) (string, error) {
+	return runCommand(dir, nil, nil, nil, "git", args...)
+}
+
+func runCommand(dir string, env []string, stdout io.Writer, stderr io.Writer, name string, args ...string) (string, error) {
+	resolvedName, err := resolveExecutable(name, env)
+	if err != nil {
+		return "", err
+	}
+	cmd := exec.Command(resolvedName, args...)
+	if dir != "" {
+		cmd.Dir = dir
+	}
+	if env != nil {
+		cmd.Env = env
+	} else {
+		cmd.Env = os.Environ()
+	}
+
+	var out bytes.Buffer
+	cmd.Stdout = io.MultiWriter(&out, writerOrDiscard(stdout))
+	cmd.Stderr = io.MultiWriter(&out, writerOrDiscard(stderr))
+	err = cmd.Run()
+	if err != nil {
+		output := strings.TrimSpace(out.String())
+		if output == "" {
+			return out.String(), fmt.Errorf("%s %s: %w", name, strings.Join(args, " "), err)
+		}
+		return out.String(), fmt.Errorf("%s %s: %w\n%s", name, strings.Join(args, " "), err, output)
+	}
+	return out.String(), nil
+}
+
+func resolveExecutable(name string, env []string) (string, error) {
+	if strings.ContainsRune(name, os.PathSeparator) {
+		return name, nil
+	}
+
+	pathValue := os.Getenv("PATH")
+	for _, entry := range env {
+		if strings.HasPrefix(entry, "PATH=") {
+			pathValue = strings.TrimPrefix(entry, "PATH=")
+		}
+	}
+
+	for _, dir := range filepath.SplitList(pathValue) {
+		if dir == "" {
+			dir = "."
+		}
+		candidate := filepath.Join(dir, name)
+		info, err := os.Stat(candidate)
+		if err != nil || info.IsDir() {
+			continue
+		}
+		if info.Mode()&0o111 == 0 {
+			continue
+		}
+		return candidate, nil
+	}
+	return "", fmt.Errorf("executable %q not found in PATH", name)
+}
+
+func writerOrDiscard(w io.Writer) io.Writer {
+	if w == nil {
+		return io.Discard
+	}
+	return w
+}

packages/release/internal/release/release_step.go

@@ -0,0 +1,64 @@
+package release
+
+import (
+	"encoding/json"
+	"fmt"
+)
+
+type ReleaseStep struct {
+	Kind        string `json:"kind"`
+	Path        string `json:"path,omitempty"`
+	Text        string `json:"text,omitempty"`
+	Regex       string `json:"regex,omitempty"`
+	Replacement string `json:"replacement,omitempty"`
+	Key         string `json:"key,omitempty"`
+	Value       string `json:"value,omitempty"`
+}
+
+func decodeReleaseSteps(raw string) ([]ReleaseStep, error) {
+	if raw == "" {
+		return nil, nil
+	}
+
+	var steps []ReleaseStep
+	if err := json.Unmarshal([]byte(raw), &steps); err != nil {
+		return nil, fmt.Errorf("decode release steps: %w", err)
+	}
+
+	for i, step := range steps {
+		if err := validateReleaseStep(step); err != nil {
+			return nil, fmt.Errorf("release step %d: %w", i+1, err)
+		}
+	}
+	return steps, nil
+}
+
+func validateReleaseStep(step ReleaseStep) error {
+	switch step.Kind {
+	case "writeFile":
+		if step.Path == "" {
+			return fmt.Errorf("writeFile.path is required")
+		}
+		return nil
+	case "replace":
+		if step.Path == "" {
+			return fmt.Errorf("replace.path is required")
+		}
+		if step.Regex == "" {
+			return fmt.Errorf("replace.regex is required")
+		}
+		return nil
+	case "versionMetaSet":
+		if step.Key == "" {
+			return fmt.Errorf("versionMetaSet.key is required")
+		}
+		return nil
+	case "versionMetaUnset":
+		if step.Key == "" {
+			return fmt.Errorf("versionMetaUnset.key is required")
+		}
+		return nil
+	default:
+		return fmt.Errorf("unsupported release step kind %q", step.Kind)
+	}
+}

packages/release/internal/release/release_step_apply.go

@@ -0,0 +1,39 @@
+package release
+
+import (
+	"fmt"
+	"io"
+)
+
+func (r *Runner) runReleaseSteps(rootDir string, versionPath string, versionFile *VersionFile, version Version, stdout io.Writer, stderr io.Writer) error {
+	steps, err := decodeReleaseSteps(r.Config.ReleaseStepsJSON)
+	if err != nil {
+		return err
+	}
+	if len(steps) == 0 {
+		return nil
+	}
+
+	ctx := newReleaseStepContext(rootDir, versionPath, versionFile, version, r.Config.Env)
+	for i, step := range steps {
+		if err := applyReleaseStep(ctx, step); err != nil {
+			return fmt.Errorf("release step %d (%s): %w", i+1, step.Kind, err)
+		}
+	}
+	return nil
+}
+
+func applyReleaseStep(ctx *ReleaseStepContext, step ReleaseStep) error {
+	switch step.Kind {
+	case "writeFile":
+		return applyWriteFileStep(ctx, step)
+	case "replace":
+		return applyReplaceStep(ctx, step)
+	case "versionMetaSet":
+		return applyVersionMetaSetStep(ctx, step)
+	case "versionMetaUnset":
+		return applyVersionMetaUnsetStep(ctx, step)
+	default:
+		return fmt.Errorf("unsupported release step kind %q", step.Kind)
+	}
+}

packages/release/internal/release/release_step_context.go

@@ -0,0 +1,73 @@
+package release
+
+import (
+	"os"
+	"path/filepath"
+	"strconv"
+	"strings"
+)
+
+type ReleaseStepContext struct {
+	RootDir     string
+	VersionPath string
+	Version     Version
+	VersionFile *VersionFile
+	Env         map[string]string
+}
+
+func newReleaseStepContext(rootDir string, versionPath string, versionFile *VersionFile, version Version, env []string) *ReleaseStepContext {
+	return &ReleaseStepContext{
+		RootDir:     rootDir,
+		VersionPath: versionPath,
+		Version:     version,
+		VersionFile: versionFile,
+		Env:         buildReleaseEnv(rootDir, versionFile, version, env),
+	}
+}
+
+func buildReleaseEnv(rootDir string, versionFile *VersionFile, version Version, baseEnv []string) map[string]string {
+	env := make(map[string]string, len(baseEnv)+8+len(versionFile.Metadata.lines))
+	if len(baseEnv) == 0 {
+		baseEnv = os.Environ()
+	}
+	for _, entry := range baseEnv {
+		key, value, ok := strings.Cut(entry, "=")
+		if ok {
+			env[key] = value
+		}
+	}
+
+	env["ROOT_DIR"] = rootDir
+	env["BASE_VERSION"] = version.BaseString()
+	env["CHANNEL"] = version.Channel
+	env["FULL_VERSION"] = version.String()
+	env["FULL_TAG"] = version.Tag()
+	if version.Channel == "stable" {
+		env["PRERELEASE_NUM"] = ""
+	} else {
+		env["PRERELEASE_NUM"] = strconv.Itoa(version.Prerelease)
+	}
+
+	for _, line := range versionFile.Metadata.lines {
+		key, value, ok := strings.Cut(line, "=")
+		if !ok || key == "" {
+			continue
+		}
+		env[sanitizeMetaEnvName(key)] = value
+	}
+	return env
+}
+
+func (c *ReleaseStepContext) expand(raw string) string {
+	return os.Expand(raw, func(name string) string {
+		return c.Env[name]
+	})
+}
+
+func (c *ReleaseStepContext) resolvePath(path string) string {
+	expanded := c.expand(path)
+	if filepath.IsAbs(expanded) {
+		return expanded
+	}
+	return filepath.Join(c.RootDir, expanded)
+}

packages/release/internal/release/release_step_replace.go

@@ -0,0 +1,44 @@
+package release
+
+import (
+	"fmt"
+	"os"
+	"regexp"
+	"strings"
+)
+
+func applyReplaceStep(ctx *ReleaseStepContext, step ReleaseStep) error {
+	targetPath := ctx.resolvePath(step.Path)
+	content, err := os.ReadFile(targetPath)
+	if err != nil {
+		return fmt.Errorf("read %s: %w", targetPath, err)
+	}
+
+	pattern, err := regexp.Compile("(?m)" + ctx.expand(step.Regex))
+	if err != nil {
+		return fmt.Errorf("compile regex for %s: %w", targetPath, err)
+	}
+
+	replacement := translateReplacementBackrefs(ctx.expand(step.Replacement))
+	updated := pattern.ReplaceAllString(string(content), replacement)
+	if err := os.WriteFile(targetPath, []byte(updated), 0o644); err != nil {
+		return fmt.Errorf("write %s: %w", targetPath, err)
+	}
+	return nil
+}
+
+func translateReplacementBackrefs(raw string) string {
+	var b strings.Builder
+	b.Grow(len(raw))
+
+	for i := 0; i < len(raw); i++ {
+		if raw[i] == '\\' && i+1 < len(raw) && raw[i+1] >= '1' && raw[i+1] <= '9' {
+			b.WriteByte('$')
+			b.WriteByte(raw[i+1])
+			i++
+			continue
+		}
+		b.WriteByte(raw[i])
+	}
+	return b.String()
+}

packages/release/internal/release/release_step_version_meta.go

@@ -0,0 +1,21 @@
+package release
+
+import "fmt"
+
+func applyVersionMetaSetStep(ctx *ReleaseStepContext, step ReleaseStep) error {
+	ctx.VersionFile.Metadata.Set(step.Key, ctx.expand(step.Value))
+	ctx.Env[sanitizeMetaEnvName(step.Key)] = ctx.VersionFile.Metadata.Get(step.Key)
+	if err := ctx.VersionFile.Write(ctx.VersionPath); err != nil {
+		return fmt.Errorf("write VERSION: %w", err)
+	}
+	return nil
+}
+
+func applyVersionMetaUnsetStep(ctx *ReleaseStepContext, step ReleaseStep) error {
+	ctx.VersionFile.Metadata.Unset(step.Key)
+	delete(ctx.Env, sanitizeMetaEnvName(step.Key))
+	if err := ctx.VersionFile.Write(ctx.VersionPath); err != nil {
+		return fmt.Errorf("write VERSION: %w", err)
+	}
+	return nil
+}

packages/release/internal/release/release_step_write_file.go

@@ -0,0 +1,18 @@
+package release
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+)
+
+func applyWriteFileStep(ctx *ReleaseStepContext, step ReleaseStep) error {
+	targetPath := ctx.resolvePath(step.Path)
+	if err := os.MkdirAll(filepath.Dir(targetPath), 0o755); err != nil {
+		return fmt.Errorf("mkdir %s: %w", filepath.Dir(targetPath), err)
+	}
+	if err := os.WriteFile(targetPath, []byte(ctx.expand(step.Text)), 0o644); err != nil {
+		return fmt.Errorf("write %s: %w", targetPath, err)
+	}
+	return nil
+}

packages/release/internal/release/release_test.go

@@ -0,0 +1,404 @@
+package release
+
+import (
+	"encoding/json"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"strings"
+	"testing"
+)
+
+func TestResolveNextVersion(t *testing.T) {
+	t.Parallel()
+
+	allowed := []string{"alpha", "beta", "rc", "internal"}
+	tests := []struct {
+		name    string
+		current string
+		args    []string
+		want    string
+		wantErr string
+	}{
+		{
+			name:    "channel only from stable bumps patch",
+			current: "1.0.0",
+			args:    []string{"beta"},
+			want:    "1.0.1-beta.1",
+		},
+		{
+			name:    "explicit minor bump keeps requested bump",
+			current: "1.0.0",
+			args:    []string{"minor", "beta"},
+			want:    "1.1.0-beta.1",
+		},
+		{
+			name:    "full promotes prerelease to stable",
+			current: "1.1.5-beta.1",
+			args:    []string{"full"},
+			want:    "1.1.5",
+		},
+		{
+			name:    "set stable from prerelease requires full",
+			current: "1.1.5-beta.1",
+			args:    []string{"set", "1.1.5"},
+			wantErr: "promote using 'stable' or 'full' only",
+		},
+		{
+			name:    "patch stable from prerelease requires full",
+			current: "1.1.5-beta.1",
+			args:    []string{"patch", "stable"},
+			wantErr: "promote using 'stable' or 'full' only",
+		},
+		{
+			name:    "full no-op fails",
+			current: "1.1.5",
+			args:    []string{"full"},
+			wantErr: "Version 1.1.5 is already current; nothing to do.",
+		},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			t.Parallel()
+
+			current, err := ParseVersion(tc.current)
+			if err != nil {
+				t.Fatalf("ParseVersion(%q): %v", tc.current, err)
+			}
+
+			got, err := ResolveNextVersion(current, tc.args, allowed)
+			if tc.wantErr != "" {
+				if err == nil {
+					t.Fatalf("ResolveNextVersion(%q, %v) succeeded, want error", tc.current, tc.args)
+				}
+				if !strings.Contains(err.Error(), tc.wantErr) {
+					t.Fatalf("ResolveNextVersion(%q, %v) error = %q, want substring %q", tc.current, tc.args, err.Error(), tc.wantErr)
+				}
+				return
+			}
+			if err != nil {
+				t.Fatalf("ResolveNextVersion(%q, %v): %v", tc.current, tc.args, err)
+			}
+			if got.String() != tc.want {
+				t.Fatalf("ResolveNextVersion(%q, %v) = %q, want %q", tc.current, tc.args, got.String(), tc.want)
+			}
+		})
+	}
+}
+
+func TestVersionFileMetadataRoundTrip(t *testing.T) {
+	t.Parallel()
+
+	dir := t.TempDir()
+	path := filepath.Join(dir, "VERSION")
+	content := strings.Join([]string{
+		"1.0.0",
+		"stable",
+		"0",
+		"desktop_backend_change_scope=bindings",
+		"desktop_release_mode=binary",
+		"desktop_unused=temporary",
+		"",
+	}, "\n")
+	if err := os.WriteFile(path, []byte(content), 0o644); err != nil {
+		t.Fatalf("WriteFile(VERSION): %v", err)
+	}
+
+	file, err := ReadVersionFile(path)
+	if err != nil {
+		t.Fatalf("ReadVersionFile: %v", err)
+	}
+
+	if got := file.Current().String(); got != "1.0.0" {
+		t.Fatalf("Current() = %q, want 1.0.0", got)
+	}
+	if got := file.Metadata.Get("desktop_backend_change_scope"); got != "bindings" {
+		t.Fatalf("Metadata.Get(scope) = %q, want bindings", got)
+	}
+
+	file.Version = MustParseVersion(t, "1.0.1")
+	file.Metadata.Set("desktop_release_mode", "codepush")
+	file.Metadata.Set("desktop_binary_version_min", "1.0.0")
+	file.Metadata.Set("desktop_binary_version_max", "1.0.1")
+	file.Metadata.Set("desktop_backend_compat_id", "compat-123")
+	file.Metadata.Unset("desktop_unused")
+
+	if err := file.Write(path); err != nil {
+		t.Fatalf("Write(VERSION): %v", err)
+	}
+
+	gotBytes, err := os.ReadFile(path)
+	if err != nil {
+		t.Fatalf("ReadFile(VERSION): %v", err)
+	}
+	got := string(gotBytes)
+	for _, needle := range []string{
+		"1.0.1\nstable\n0\n",
+		"desktop_backend_change_scope=bindings",
+		"desktop_release_mode=codepush",
+		"desktop_binary_version_min=1.0.0",
+		"desktop_binary_version_max=1.0.1",
+		"desktop_backend_compat_id=compat-123",
+	} {
+		if !strings.Contains(got, needle) {
+			t.Fatalf("VERSION missing %q:\n%s", needle, got)
+		}
+	}
+	if strings.Contains(got, "desktop_unused=temporary") {
+		t.Fatalf("VERSION still contains removed metadata:\n%s", got)
+	}
+}
+
+func TestRunnerExecutesReleaseFlow(t *testing.T) {
+	t.Parallel()
+
+	root := t.TempDir()
+	remote := filepath.Join(t.TempDir(), "remote.git")
+	mustRun(t, root, "git", "init")
+	mustRun(t, root, "git", "config", "user.name", "Release Test")
+	mustRun(t, root, "git", "config", "user.email", "release-test@example.com")
+	mustRun(t, root, "git", "config", "commit.gpgsign", "false")
+	mustRun(t, root, "git", "config", "tag.gpgsign", "false")
+	if err := os.WriteFile(filepath.Join(root, "flake.nix"), []byte("{ outputs = { self }: {}; }\n"), 0o644); err != nil {
+		t.Fatalf("WriteFile(flake.nix): %v", err)
+	}
+	if err := os.WriteFile(filepath.Join(root, "VERSION"), []byte("1.0.0\nstable\n0\ndesktop_backend_change_scope=bindings\ndesktop_release_mode=binary\ndesktop_unused=temporary\n"), 0o644); err != nil {
+		t.Fatalf("WriteFile(VERSION): %v", err)
+	}
+	if err := os.WriteFile(filepath.Join(root, "notes.txt"), []byte("version=old\n"), 0o644); err != nil {
+		t.Fatalf("WriteFile(notes.txt): %v", err)
+	}
+	mustRun(t, root, "git", "add", "-A")
+	mustRun(t, root, "git", "commit", "-m", "init")
+	mustRun(t, root, "git", "init", "--bare", remote)
+	mustRun(t, root, "git", "remote", "add", "origin", remote)
+	mustRun(t, root, "git", "push", "-u", "origin", "HEAD")
+
+	binDir := t.TempDir()
+	if err := os.MkdirAll(binDir, 0o755); err != nil {
+		t.Fatalf("MkdirAll(bin): %v", err)
+	}
+	nixPath := filepath.Join(binDir, "nix")
+	nixScript := "#!/usr/bin/env bash\nif [[ \"${1-}\" == \"fmt\" ]]; then\n  exit 0\nfi\necho \"unexpected nix invocation: $*\" >&2\nexit 1\n"
+	if err := os.WriteFile(nixPath, []byte(nixScript), 0o755); err != nil {
+		t.Fatalf("WriteFile(bin/nix): %v", err)
+	}
+
+	r := &Runner{
+		Config: Config{
+			RootDir:         root,
+			AllowedChannels: []string{"alpha", "beta", "rc", "internal"},
+			ReleaseStepsJSON: mustJSON(t, []ReleaseStep{
+				{Kind: "writeFile", Path: "generated/version.txt", Text: "$FULL_VERSION\n"},
+				{Kind: "replace", Path: "notes.txt", Regex: "^version=.*$", Replacement: "version=$FULL_VERSION"},
+				{Kind: "writeFile", Path: "release.tag", Text: "$FULL_TAG\n"},
+				{Kind: "writeFile", Path: "metadata/scope.txt", Text: "$VERSION_META_DESKTOP_BACKEND_CHANGE_SCOPE\n"},
+				{Kind: "writeFile", Path: "metadata/mode-before.txt", Text: "$VERSION_META_DESKTOP_RELEASE_MODE\n"},
+				{Kind: "versionMetaSet", Key: "desktop_release_mode", Value: "codepush"},
+				{Kind: "versionMetaSet", Key: "desktop_binary_version_min", Value: "1.0.0"},
+				{Kind: "versionMetaSet", Key: "desktop_binary_version_max", Value: "$FULL_VERSION"},
+				{Kind: "versionMetaSet", Key: "desktop_backend_compat_id", Value: "compat-123"},
+				{Kind: "versionMetaUnset", Key: "desktop_unused"},
+			}),
+			PostVersion: "printf '%s\\n' \"$FULL_VERSION\" >\"$ROOT_DIR/post-version.txt\"",
+			Execution: ExecutionOptions{
+				Commit: true,
+				Tag:    true,
+				Push:   true,
+			},
+			Env: append(os.Environ(), "PATH="+binDir+string(os.PathListSeparator)+os.Getenv("PATH")),
+		},
+	}
+
+	if err := r.Run([]string{"patch"}); err != nil {
+		t.Fatalf("Runner.Run: %v", err)
+	}
+
+	versionFile, err := ReadVersionFile(filepath.Join(root, "VERSION"))
+	if err != nil {
+		t.Fatalf("ReadVersionFile(after): %v", err)
+	}
+	if got := versionFile.Current().String(); got != "1.0.1" {
+		t.Fatalf("Current() after release = %q, want 1.0.1", got)
+	}
+
+	assertFileEquals(t, filepath.Join(root, "generated/version.txt"), "1.0.1\n")
+	assertFileEquals(t, filepath.Join(root, "notes.txt"), "version=1.0.1\n")
+	assertFileEquals(t, filepath.Join(root, "release.tag"), "v1.0.1\n")
+	assertFileEquals(t, filepath.Join(root, "metadata/scope.txt"), "bindings\n")
+	assertFileEquals(t, filepath.Join(root, "metadata/mode-before.txt"), "binary\n")
+	assertFileEquals(t, filepath.Join(root, "post-version.txt"), "1.0.1\n")
+
+	versionBytes, err := os.ReadFile(filepath.Join(root, "VERSION"))
+	if err != nil {
+		t.Fatalf("ReadFile(VERSION after): %v", err)
+	}
+	versionText := string(versionBytes)
+	for _, needle := range []string{
+		"desktop_backend_change_scope=bindings",
+		"desktop_release_mode=codepush",
+		"desktop_binary_version_min=1.0.0",
+		"desktop_binary_version_max=1.0.1",
+		"desktop_backend_compat_id=compat-123",
+	} {
+		if !strings.Contains(versionText, needle) {
+			t.Fatalf("VERSION missing %q:\n%s", needle, versionText)
+		}
+	}
+	if strings.Contains(versionText, "desktop_unused=temporary") {
+		t.Fatalf("VERSION still contains removed metadata:\n%s", versionText)
+	}
+
+	tagList := strings.TrimSpace(mustOutput(t, root, "git", "tag", "--list", "v1.0.1"))
+	if tagList != "v1.0.1" {
+		t.Fatalf("git tag --list v1.0.1 = %q, want v1.0.1", tagList)
+	}
+}
+
+func TestRunnerLeavesChangesUncommittedByDefault(t *testing.T) {
+	t.Parallel()
+
+	root := t.TempDir()
+	mustRun(t, root, "git", "init")
+	mustRun(t, root, "git", "config", "user.name", "Release Test")
+	mustRun(t, root, "git", "config", "user.email", "release-test@example.com")
+	if err := os.WriteFile(filepath.Join(root, "flake.nix"), []byte("{ outputs = { self }: {}; }\n"), 0o644); err != nil {
+		t.Fatalf("WriteFile(flake.nix): %v", err)
+	}
+	if err := os.WriteFile(filepath.Join(root, "VERSION"), []byte("1.0.0\nstable\n0\n"), 0o644); err != nil {
+		t.Fatalf("WriteFile(VERSION): %v", err)
+	}
+	mustRun(t, root, "git", "add", "-A")
+	mustRun(t, root, "git", "commit", "-m", "init")
+
+	binDir := t.TempDir()
+	if err := os.MkdirAll(binDir, 0o755); err != nil {
+		t.Fatalf("MkdirAll(bin): %v", err)
+	}
+	nixPath := filepath.Join(binDir, "nix")
+	nixScript := "#!/usr/bin/env bash\nif [[ \"${1-}\" == \"fmt\" ]]; then\n  exit 0\nfi\necho \"unexpected nix invocation: $*\" >&2\nexit 1\n"
+	if err := os.WriteFile(nixPath, []byte(nixScript), 0o755); err != nil {
+		t.Fatalf("WriteFile(bin/nix): %v", err)
+	}
+
+	r := &Runner{
+		Config: Config{
+			RootDir:         root,
+			AllowedChannels: []string{"alpha", "beta", "rc", "internal"},
+			Env:             append(os.Environ(), "PATH="+binDir+string(os.PathListSeparator)+os.Getenv("PATH")),
+		},
+	}
+
+	if err := r.Run([]string{"patch"}); err != nil {
+		t.Fatalf("Runner.Run: %v", err)
+	}
+
+	assertFileEquals(t, filepath.Join(root, "VERSION"), "1.0.1\nstable\n0\n")
+	status := strings.TrimSpace(mustOutput(t, root, "git", "status", "--short"))
+	if status != "M VERSION" {
+		t.Fatalf("git status --short = %q, want %q", status, "M VERSION")
+	}
+
+	tagList := strings.TrimSpace(mustOutput(t, root, "git", "tag", "--list"))
+	if tagList != "" {
+		t.Fatalf("git tag --list = %q, want empty", tagList)
+	}
+}
+
+func TestRunnerDryRunDoesNotModifyRepo(t *testing.T) {
+	t.Parallel()
+
+	root := t.TempDir()
+	mustRun(t, root, "git", "init")
+	mustRun(t, root, "git", "config", "user.name", "Release Test")
+	mustRun(t, root, "git", "config", "user.email", "release-test@example.com")
+	if err := os.WriteFile(filepath.Join(root, "flake.nix"), []byte("{ outputs = { self }: {}; }\n"), 0o644); err != nil {
+		t.Fatalf("WriteFile(flake.nix): %v", err)
+	}
+	if err := os.WriteFile(filepath.Join(root, "VERSION"), []byte("1.0.0\nstable\n0\n"), 0o644); err != nil {
+		t.Fatalf("WriteFile(VERSION): %v", err)
+	}
+	mustRun(t, root, "git", "add", "-A")
+	mustRun(t, root, "git", "commit", "-m", "init")
+
+	var stdout strings.Builder
+	r := &Runner{
+		Config: Config{
+			RootDir:         root,
+			AllowedChannels: []string{"alpha", "beta", "rc", "internal"},
+			Execution: ExecutionOptions{
+				DryRun: true,
+				Commit: true,
+				Tag:    true,
+				Push:   true,
+			},
+			Stdout: &stdout,
+		},
+	}
+
+	if err := r.Run([]string{"patch"}); err != nil {
+		t.Fatalf("Runner.Run: %v", err)
+	}
+
+	assertFileEquals(t, filepath.Join(root, "VERSION"), "1.0.0\nstable\n0\n")
+	status := strings.TrimSpace(mustOutput(t, root, "git", "status", "--short"))
+	if status != "" {
+		t.Fatalf("git status --short = %q, want empty", status)
+	}
+	if !strings.Contains(stdout.String(), "Dry run: 1.0.1") {
+		t.Fatalf("dry-run output missing next version:\n%s", stdout.String())
+	}
+}
+
+func MustParseVersion(t *testing.T, raw string) Version {
+	t.Helper()
+	v, err := ParseVersion(raw)
+	if err != nil {
+		t.Fatalf("ParseVersion(%q): %v", raw, err)
+	}
+	return v
+}
+
+func mustJSON(t *testing.T, value any) string {
+	t.Helper()
+	data, err := json.Marshal(value)
+	if err != nil {
+		t.Fatalf("json.Marshal: %v", err)
+	}
+	return string(data)
+}
+
+func mustRun(t *testing.T, dir string, name string, args ...string) {
+	t.Helper()
+	cmd := exec.Command(name, args...)
+	cmd.Dir = dir
+	cmd.Env = os.Environ()
+	out, err := cmd.CombinedOutput()
+	if err != nil {
+		t.Fatalf("%s %s failed: %v\n%s", name, strings.Join(args, " "), err, string(out))
+	}
+}
+
+func mustOutput(t *testing.T, dir string, name string, args ...string) string {
+	t.Helper()
+	cmd := exec.Command(name, args...)
+	cmd.Dir = dir
+	cmd.Env = os.Environ()
+	out, err := cmd.CombinedOutput()
+	if err != nil {
+		t.Fatalf("%s %s failed: %v\n%s", name, strings.Join(args, " "), err, string(out))
+	}
+	return string(out)
+}
+
+func assertFileEquals(t *testing.T, path string, want string) {
+	t.Helper()
+	gotBytes, err := os.ReadFile(path)
+	if err != nil {
+		t.Fatalf("ReadFile(%s): %v", path, err)
+	}
+	if got := string(gotBytes); got != want {
+		t.Fatalf("%s = %q, want %q", path, got, want)
+	}
+}

packages/release/internal/release/runner.go

@@ -0,0 +1,160 @@
+package release
+
+import (
+	"fmt"
+	"io"
+	"os"
+	"path/filepath"
+	"strings"
+)
+
+type Config struct {
+	RootDir          string
+	AllowedChannels  []string
+	ReleaseStepsJSON string
+	PostVersion      string
+	Execution        ExecutionOptions
+	Env              []string
+	Stdout           io.Writer
+	Stderr           io.Writer
+}
+
+type ExecutionOptions struct {
+	DryRun bool
+	Commit bool
+	Tag    bool
+	Push   bool
+}
+
+type Runner struct {
+	Config Config
+}
+
+func (o ExecutionOptions) Normalize() ExecutionOptions {
+	if o.Push {
+		o.Commit = true
+	}
+	if o.Tag {
+		o.Commit = true
+	}
+	return o
+}
+
+func (r *Runner) Run(args []string) error {
+	rootDir, err := r.rootDir()
+	if err != nil {
+		return err
+	}
+
+	stdout := writerOrDiscard(r.Config.Stdout)
+	stderr := writerOrDiscard(r.Config.Stderr)
+	execution := r.Config.Execution.Normalize()
+
+	versionFile, versionPath, err := r.loadVersionFile(rootDir)
+	if err != nil {
+		return err
+	}
+
+	nextVersion, err := ResolveNextVersion(versionFile.Version, args, r.Config.AllowedChannels)
+	if err != nil {
+		return err
+	}
+
+	if execution.DryRun {
+		printReleasePlan(stdout, nextVersion, execution, strings.TrimSpace(r.Config.ReleaseStepsJSON) != "", strings.TrimSpace(r.Config.PostVersion) != "")
+		return nil
+	}
+
+	if err := requireCleanGit(rootDir); err != nil {
+		return err
+	}
+
+	versionFile.Version = nextVersion
+	if err := versionFile.Write(versionPath); err != nil {
+		return err
+	}
+	if err := r.runReleaseSteps(rootDir, versionPath, versionFile, nextVersion, stdout, stderr); err != nil {
+		return err
+	}
+	if err := r.runShell(rootDir, versionFile, nextVersion, r.Config.PostVersion, stdout, stderr); err != nil {
+		return err
+	}
+
+	if err := r.finalizeRelease(rootDir, nextVersion, execution, stdout, stderr); err != nil {
+		return err
+	}
+	return nil
+}
+
+func (r *Runner) rootDir() (string, error) {
+	if r.Config.RootDir != "" {
+		return r.Config.RootDir, nil
+	}
+	rootDir, err := gitOutput("", "rev-parse", "--show-toplevel")
+	if err != nil {
+		return "", err
+	}
+	return strings.TrimSpace(rootDir), nil
+}
+
+func (r *Runner) loadVersionFile(rootDir string) (*VersionFile, string, error) {
+	versionPath := filepath.Join(rootDir, "VERSION")
+	if _, err := os.Stat(versionPath); err != nil {
+		return nil, "", fmt.Errorf("VERSION file not found at %s", versionPath)
+	}
+	versionFile, err := ReadVersionFile(versionPath)
+	if err != nil {
+		return nil, "", err
+	}
+	return versionFile, versionPath, nil
+}
+
+func (r *Runner) finalizeRelease(rootDir string, version Version, execution ExecutionOptions, stdout io.Writer, stderr io.Writer) error {
+	if _, err := runCommand(rootDir, r.Config.Env, stdout, stderr, "nix", "fmt"); err != nil {
+		return err
+	}
+
+	if !execution.Commit {
+		return nil
+	}
+
+	if _, err := runCommand(rootDir, r.Config.Env, stdout, stderr, "git", "add", "-A"); err != nil {
+		return err
+	}
+
+	commitMsg := "chore(release): " + version.Tag()
+	if _, err := runCommand(rootDir, r.Config.Env, stdout, stderr, "git", "commit", "-m", commitMsg); err != nil {
+		return err
+	}
+
+	if execution.Tag {
+		if _, err := runCommand(rootDir, r.Config.Env, stdout, stderr, "git", "tag", version.Tag()); err != nil {
+			return err
+		}
+	}
+
+	if !execution.Push {
+		return nil
+	}
+
+	if _, err := runCommand(rootDir, r.Config.Env, stdout, stderr, "git", "push"); err != nil {
+		return err
+	}
+	if execution.Tag {
+		if _, err := runCommand(rootDir, r.Config.Env, stdout, stderr, "git", "push", "--tags"); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func printReleasePlan(stdout io.Writer, version Version, execution ExecutionOptions, hasReleaseSteps bool, hasPostVersion bool) {
+	fmt.Fprintf(stdout, "Dry run: %s\n", version.String())
+	fmt.Fprintf(stdout, "Tag: %s\n", version.Tag())
+	fmt.Fprintf(stdout, "Release steps: %s\n", yesNo(hasReleaseSteps))
+	fmt.Fprintf(stdout, "Post-version: %s\n", yesNo(hasPostVersion))
+	fmt.Fprintf(stdout, "nix fmt: yes\n")
+	fmt.Fprintf(stdout, "git commit: %s\n", yesNo(execution.Commit))
+	fmt.Fprintf(stdout, "git tag: %s\n", yesNo(execution.Tag))
+	fmt.Fprintf(stdout, "git push: %s\n", yesNo(execution.Push))
+}

packages/release/internal/release/shell.go

@@ -0,0 +1,90 @@
+package release
+
+import (
+	"io"
+	"strings"
+)
+
+const shellPrelude = `
+log() { echo "[release] $*" >&2; }
+version_meta_get() {
+  local key="${1-}"
+  local line
+  while IFS= read -r line; do
+    [[ $line == "$key="* ]] && printf '%s\n' "${line#*=}" && return 0
+  done < <(tail -n +4 "$ROOT_DIR/VERSION" 2>/dev/null || true)
+  return 1
+}
+version_meta_set() {
+  local key="${1-}"
+  local value="${2-}"
+  local tmp
+  tmp="$(mktemp)"
+  awk -v key="$key" -v value="$value" '
+    NR <= 3 { print; next }
+    $0 ~ ("^" key "=") { print key "=" value; updated=1; next }
+    { print }
+    END { if (!updated) print key "=" value }
+  ' "$ROOT_DIR/VERSION" >"$tmp"
+  mv "$tmp" "$ROOT_DIR/VERSION"
+  export_version_meta_env
+}
+version_meta_unset() {
+  local key="${1-}"
+  local tmp
+  tmp="$(mktemp)"
+  awk -v key="$key" '
+    NR <= 3 { print; next }
+    $0 ~ ("^" key "=") { next }
+    { print }
+  ' "$ROOT_DIR/VERSION" >"$tmp"
+  mv "$tmp" "$ROOT_DIR/VERSION"
+  export_version_meta_env
+}
+export_version_meta_env() {
+  local line key value env_key
+  while IFS= read -r line; do
+    [[ $line == *=* ]] || continue
+    key="${line%%=*}"
+    value="${line#*=}"
+    env_key="$(printf '%s' "$key" | tr -c '[:alnum:]' '_' | tr '[:lower:]' '[:upper:]')"
+    export "VERSION_META_${env_key}=$value"
+  done < <(tail -n +4 "$ROOT_DIR/VERSION" 2>/dev/null || true)
+}
+export_version_meta_env
+`
+
+func (r *Runner) runShell(rootDir string, versionFile *VersionFile, version Version, script string, stdout io.Writer, stderr io.Writer) error {
+	if strings.TrimSpace(script) == "" {
+		return nil
+	}
+
+	env := r.shellEnv(rootDir, versionFile, version)
+	_, err := runCommand(rootDir, env, stdout, stderr, "bash", "-euo", "pipefail", "-c", shellPrelude+"\n"+script)
+	return err
+}
+
+func (r *Runner) shellEnv(rootDir string, versionFile *VersionFile, version Version) []string {
+	envMap := buildReleaseEnv(rootDir, versionFile, version, r.Config.Env)
+	env := make([]string, 0, len(envMap))
+	for key, value := range envMap {
+		env = append(env, key+"="+value)
+	}
+	return env
+}
+
+func sanitizeMetaEnvName(key string) string {
+	var b strings.Builder
+	b.WriteString("VERSION_META_")
+	for _, r := range key {
+		switch {
+		case r >= 'a' && r <= 'z':
+			b.WriteRune(r - 32)
+		case r >= 'A' && r <= 'Z', r >= '0' && r <= '9':
+			b.WriteRune(r)
+		default:
+			b.WriteByte('_')
+		}
+	}
+	return b.String()
+}

packages/release/internal/release/slices.go

@@ -0,0 +1,10 @@
+package release
+
+func contains(values []string, target string) bool {
+	for _, value := range values {
+		if value == target {
+			return true
+		}
+	}
+	return false
+}

packages/release/internal/release/ui.go

@@ -0,0 +1,350 @@
+package release
+
+import (
+	"fmt"
+	"io"
+	"os"
+	"strings"
+
+	tea "github.com/charmbracelet/bubbletea"
+	"golang.org/x/term"
+)
+
+type CommandOption struct {
+	Title       string
+	Description string
+	Command     string
+	Args        []string
+	NextVersion Version
+	Preview     string
+}
+
+func IsInteractiveTerminal(stdin io.Reader, stdout io.Writer) bool {
+	in, inOK := stdin.(*os.File)
+	out, outOK := stdout.(*os.File)
+	if !inOK || !outOK {
+		return false
+	}
+	return term.IsTerminal(int(in.Fd())) && term.IsTerminal(int(out.Fd()))
+}
+
+func SelectCommand(config Config) ([]string, bool, error) {
+	r := &Runner{Config: config}
+	rootDir, err := r.rootDir()
+	if err != nil {
+		return nil, false, err
+	}
+
+	versionFile, _, err := r.loadVersionFile(rootDir)
+	if err != nil {
+		return nil, false, err
+	}
+
+	options := BuildCommandOptions(config, versionFile.Version)
+	if len(options) == 0 {
+		return nil, false, fmt.Errorf("no release commands available for current version %s", versionFile.Version.String())
+	}
+
+	model := newCommandPickerModel(versionFile.Version, options)
+	finalModel, err := tea.NewProgram(model, tea.WithAltScreen()).Run()
+	if err != nil {
+		return nil, false, err
+	}
+
+	result := finalModel.(commandPickerModel)
+	if !result.confirmed {
+		return nil, false, nil
+	}
+	return append([]string(nil), result.selected.Args...), true, nil
+}
+
+func BuildCommandOptions(config Config, current Version) []CommandOption {
+	var options []CommandOption
+	seen := map[string]struct{}{}
+	for _, args := range candidateCommandArgs(current, config.AllowedChannels) {
+		command := formatReleaseCommand(args)
+		if _, exists := seen[command]; exists {
+			continue
+		}
+
+		next, err := ResolveNextVersion(current, args, config.AllowedChannels)
+		if err != nil {
+			continue
+		}
+
+		options = append(options, CommandOption{
+			Title:       titleForArgs(args),
+			Description: descriptionForArgs(current, args, next),
+			Command:     command,
+			Args:        append([]string(nil), args...),
+			NextVersion: next,
+			Preview:     buildPreview(config, current, args, next),
+		})
+		seen[command] = struct{}{}
+	}
+	return options
+}
+
+func candidateCommandArgs(current Version, allowedChannels []string) [][]string {
+	candidates := [][]string{
+		{"patch"},
+		{"minor"},
+		{"major"},
+	}
+	if current.Channel != "stable" {
+		candidates = append([][]string{{"stable"}}, candidates...)
+	}
+	for _, channel := range allowedChannels {
+		candidates = append(candidates,
+			[]string{channel},
+			[]string{"minor", channel},
+			[]string{"major", channel},
+		)
+	}
+	return candidates
+}
+
+func formatReleaseCommand(args []string) string {
+	return formatReleaseCommandWithExecution(args, ExecutionOptions{})
+}
+
+func formatReleaseCommandWithExecution(args []string, execution ExecutionOptions) string {
+	var parts []string
+	parts = append(parts, "release")
+	if execution.DryRun {
+		parts = append(parts, "--dry-run")
+	}
+	if execution.Commit {
+		parts = append(parts, "--commit")
+	}
+	if execution.Tag {
+		parts = append(parts, "--tag")
+	}
+	if execution.Push {
+		parts = append(parts, "--push")
+	}
+	if len(args) == 0 {
+		return strings.Join(parts, " ")
+	}
+	return strings.Join(append(parts, args...), " ")
+}
+
+func titleForArgs(args []string) string {
+	if len(args) == 0 {
+		return "Patch release"
+	}
+
+	switch len(args) {
+	case 1:
+		switch args[0] {
+		case "patch":
+			return "Patch release"
+		case "minor":
+			return "Minor release"
+		case "major":
+			return "Major release"
+		case "stable":
+			return "Promote to stable"
+		default:
+			return strings.ToUpper(args[0][:1]) + args[0][1:] + " prerelease"
+		}
+	case 2:
+		return capitalize(args[0]) + " " + args[1]
+	default:
+		return strings.Join(args, " ")
+	}
+}
+
+func descriptionForArgs(current Version, args []string, next Version) string {
+	switch len(args) {
+	case 1:
+		switch args[0] {
+		case "patch":
+			return "Bump patch and keep the current channel."
+		case "minor":
+			return "Bump minor and keep the current channel."
+		case "major":
+			return "Bump major and keep the current channel."
+		case "stable":
+			return "Promote the current prerelease to a stable release."
+		default:
+			if current.Channel == args[0] && current.Channel != "stable" {
+				return "Advance the current prerelease number."
+			}
+			return "Switch to the " + args[0] + " channel."
+		}
+	case 2:
+		return fmt.Sprintf("Bump %s and publish to %s.", args[0], args[1])
+	default:
+		return "Release " + next.String() + "."
+	}
+}
+
+func buildPreview(config Config, current Version, args []string, next Version) string {
+	execution := config.Execution.Normalize()
+	var lines []string
+	lines = append(lines,
+		"Command",
+		"  "+formatReleaseCommandWithExecution(args, execution),
+		"",
+		"Version",
+		"  Current: "+current.String(),
+		"  Next:    "+next.String(),
+		"  Tag:     "+next.Tag(),
+		"",
+		"Flow",
+		"  Release steps: "+yesNo(strings.TrimSpace(config.ReleaseStepsJSON) != ""),
+		"  Post-version:  "+yesNo(strings.TrimSpace(config.PostVersion) != ""),
+		"  nix fmt:       yes",
+		"  git commit:    "+yesNo(execution.Commit),
+		"  git tag:       "+yesNo(execution.Tag),
+		"  git push:      "+yesNo(execution.Push),
+		"  dry run:       "+yesNo(execution.DryRun),
+	)
+	return strings.Join(lines, "\n")
+}
+
+func yesNo(v bool) string {
+	if v {
+		return "yes"
+	}
+	return "no"
+}
+
+func capitalize(s string) string {
+	if s == "" {
+		return s
+	}
+	runes := []rune(s)
+	first := runes[0]
+	if first >= 'a' && first <= 'z' {
+		runes[0] = first - 32
+	}
+	return string(runes)
+}
+
+type commandPickerModel struct {
+	current   Version
+	options   []CommandOption
+	cursor    int
+	width     int
+	height    int
+	confirmed bool
+	selected  CommandOption
+}
+
+func newCommandPickerModel(current Version, options []CommandOption) commandPickerModel {
+	return commandPickerModel{
+		current: current,
+		options: options,
+	}
+}
+
+func (m commandPickerModel) Init() tea.Cmd {
+	return nil
+}
+
+func (m commandPickerModel) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
+	switch msg := msg.(type) {
+	case tea.WindowSizeMsg:
+		m.width = msg.Width
+		m.height = msg.Height
+	case tea.KeyMsg:
+		switch msg.String() {
+		case "ctrl+c", "q", "esc":
+			return m, tea.Quit
+		case "up", "k":
+			if m.cursor > 0 {
+				m.cursor--
+			}
+		case "down", "j":
+			if m.cursor < len(m.options)-1 {
+				m.cursor++
+			}
+		case "enter":
+			m.confirmed = true
+			m.selected = m.options[m.cursor]
+			return m, tea.Quit
+		}
+	}
+	return m, nil
+}
+
+func (m commandPickerModel) View() string {
+	if len(m.options) == 0 {
+		return "No release commands available.\n"
+	}
+
+	preview := m.options[m.cursor].Preview
+	header := fmt.Sprintf("Release command picker\nCurrent version: %s\nUse up/down or j/k to choose, Enter to run, q to cancel.\n", m.current.String())
+
+	listLines := make([]string, 0, len(m.options)+1)
+	listLines = append(listLines, "Commands")
+	for i, option := range m.options {
+		cursor := "  "
+		if i == m.cursor {
+			cursor = "> "
+		}
+		listLines = append(listLines, fmt.Sprintf("%s%s\n  %s", cursor, option.Command, option.Description))
+	}
+	list := strings.Join(listLines, "\n")
+
+	if m.width >= 100 {
+		return header + "\n" + renderColumns(list, preview, m.width)
+	}
+	return header + "\n" + list + "\n\n" + preview + "\n"
+}
+
+func renderColumns(left string, right string, width int) string {
+	if width < 40 {
+		return left + "\n\n" + right
+	}
+
+	leftWidth := width / 2
+	rightWidth := width - leftWidth - 3
+	leftLines := strings.Split(left, "\n")
+	rightLines := strings.Split(right, "\n")
+	maxLines := len(leftLines)
+	if len(rightLines) > maxLines {
+		maxLines = len(rightLines)
+	}
+
+	var b strings.Builder
+	for i := 0; i < maxLines; i++ {
+		leftLine := ""
+		if i < len(leftLines) {
+			leftLine = leftLines[i]
+		}
+		rightLine := ""
+		if i < len(rightLines) {
+			rightLine = rightLines[i]
+		}
+		b.WriteString(padRight(trimRunes(leftLine, leftWidth), leftWidth))
+		b.WriteString(" | ")
+		b.WriteString(trimRunes(rightLine, rightWidth))
+		b.WriteByte('\n')
+	}
+	return b.String()
+}
+
+func padRight(s string, width int) string {
+	missing := width - len([]rune(s))
+	if missing <= 0 {
+		return s
+	}
+	return s + strings.Repeat(" ", missing)
+}
+
+func trimRunes(s string, width int) string {
+	runes := []rune(s)
+	if len(runes) <= width {
+		return s
+	}
+	if width <= 1 {
+		return string(runes[:width])
+	}
+	if width <= 3 {
+		return string(runes[:width])
+	}
+	return string(runes[:width-3]) + "..."
+}

packages/release/internal/release/ui_test.go

@@ -0,0 +1,91 @@
+package release
+
+import (
+	"strings"
+	"testing"
+)
+
+func TestBuildCommandOptionsForStableVersion(t *testing.T) {
+	t.Parallel()
+
+	current := MustParseVersion(t, "1.0.0")
+	options := BuildCommandOptions(Config{
+		AllowedChannels:  []string{"alpha", "beta"},
+		ReleaseStepsJSON: `[{"kind":"writeFile","path":"VERSION.txt","text":"$FULL_VERSION\n"}]`,
+		PostVersion:      "echo post",
+		Execution: ExecutionOptions{
+			Commit: true,
+			Tag:    true,
+			Push:   true,
+		},
+	}, current)
+
+	want := map[string]string{
+		"release patch":      "1.0.1",
+		"release minor":      "1.1.0",
+		"release major":      "2.0.0",
+		"release alpha":      "1.0.1-alpha.1",
+		"release minor beta": "1.1.0-beta.1",
+	}
+
+	for command, nextVersion := range want {
+		option, ok := findOptionByCommand(options, command)
+		if !ok {
+			t.Fatalf("expected command %q in options", command)
+		}
+		if option.NextVersion.String() != nextVersion {
+			t.Fatalf("%s next version = %q, want %q", command, option.NextVersion.String(), nextVersion)
+		}
+		if !strings.Contains(option.Preview, "Release steps: yes") {
+			t.Fatalf("%s preview missing release steps marker:\n%s", command, option.Preview)
+		}
+		if !strings.Contains(option.Preview, "Post-version:  yes") {
+			t.Fatalf("%s preview missing post-version marker:\n%s", command, option.Preview)
+		}
+		if !strings.Contains(option.Preview, "git push:      yes") {
+			t.Fatalf("%s preview missing git push marker:\n%s", command, option.Preview)
+		}
+	}
+}
+
+func TestBuildCommandOptionsForPrereleaseVersion(t *testing.T) {
+	t.Parallel()
+
+	current := MustParseVersion(t, "1.2.3-beta.2")
+	options := BuildCommandOptions(Config{
+		AllowedChannels: []string{"alpha", "beta", "rc"},
+	}, current)
+
+	stableOption, ok := findOptionByCommand(options, "release stable")
+	if !ok {
+		t.Fatalf("expected release stable option")
+	}
+	if stableOption.NextVersion.String() != "1.2.3" {
+		t.Fatalf("release stable next version = %q, want 1.2.3", stableOption.NextVersion.String())
+	}
+
+	betaOption, ok := findOptionByCommand(options, "release beta")
+	if !ok {
+		t.Fatalf("expected release beta option")
+	}
+	if betaOption.NextVersion.String() != "1.2.3-beta.3" {
+		t.Fatalf("release beta next version = %q, want 1.2.3-beta.3", betaOption.NextVersion.String())
+	}
+
+	patchOption, ok := findOptionByCommand(options, "release patch")
+	if !ok {
+		t.Fatalf("expected release patch option")
+	}
+	if patchOption.NextVersion.String() != "1.2.4-beta.1" {
+		t.Fatalf("release patch next version = %q, want 1.2.4-beta.1", patchOption.NextVersion.String())
+	}
+}
+
+func findOptionByCommand(options []CommandOption, command string) (CommandOption, bool) {
+	for _, option := range options {
+		if option.Command == command {
+			return option, true
+		}
+	}
+	return CommandOption{}, false
+}

packages/release/internal/release/version.go

@@ -0,0 +1,261 @@
+package release
+
+import (
+	"errors"
+	"fmt"
+	"regexp"
+	"sort"
+	"strconv"
+	"strings"
+)
+
+var versionPattern = regexp.MustCompile(`^([0-9]+)\.([0-9]+)\.([0-9]+)(?:-([A-Za-z]+)\.([0-9]+))?$`)
+
+type Version struct {
+	Major      int
+	Minor      int
+	Patch      int
+	Channel    string
+	Prerelease int
+}
+
+func ParseVersion(raw string) (Version, error) {
+	match := versionPattern.FindStringSubmatch(raw)
+	if match == nil {
+		return Version{}, fmt.Errorf("invalid version %q (expected x.y.z or x.y.z-channel.N)", raw)
+	}
+
+	major, _ := strconv.Atoi(match[1])
+	minor, _ := strconv.Atoi(match[2])
+	patch, _ := strconv.Atoi(match[3])
+	v := Version{
+		Major:   major,
+		Minor:   minor,
+		Patch:   patch,
+		Channel: "stable",
+	}
+	if match[4] != "" {
+		pre, _ := strconv.Atoi(match[5])
+		v.Channel = match[4]
+		v.Prerelease = pre
+	}
+	return v, nil
+}
+
+func (v Version) String() string {
+	if v.Channel == "" || v.Channel == "stable" {
+		return fmt.Sprintf("%d.%d.%d", v.Major, v.Minor, v.Patch)
+	}
+	return fmt.Sprintf("%d.%d.%d-%s.%d", v.Major, v.Minor, v.Patch, v.Channel, v.Prerelease)
+}
+
+func (v Version) BaseString() string {
+	return fmt.Sprintf("%d.%d.%d", v.Major, v.Minor, v.Patch)
+}
+
+func (v Version) Tag() string {
+	return "v" + v.String()
+}
+
+func (v Version) cmp(other Version) int {
+	if v.Major != other.Major {
+		return compareInt(v.Major, other.Major)
+	}
+	if v.Minor != other.Minor {
+		return compareInt(v.Minor, other.Minor)
+	}
+	if v.Patch != other.Patch {
+		return compareInt(v.Patch, other.Patch)
+	}
+	if v.Channel == "stable" && other.Channel != "stable" {
+		return 1
+	}
+	if v.Channel != "stable" && other.Channel == "stable" {
+		return -1
+	}
+	if v.Channel == "stable" && other.Channel == "stable" {
+		return 0
+	}
+	if v.Channel != other.Channel {
+		return comparePrerelease(v.Channel, other.Channel)
+	}
+	return compareInt(v.Prerelease, other.Prerelease)
+}
+
+func ResolveNextVersion(current Version, args []string, allowedChannels []string) (Version, error) {
+	currentFull := current.String()
+	action := ""
+	rest := args
+	if len(rest) > 0 {
+		action = rest[0]
+		rest = rest[1:]
+	}
+
+	if action == "set" {
+		return resolveSetVersion(current, currentFull, rest, allowedChannels)
+	}
+
+	part := ""
+	targetChannel := ""
+	wasChannelOnly := false
+
+	switch action {
+	case "":
+		part = "patch"
+	case "major", "minor", "patch":
+		part = action
+		if len(rest) > 0 {
+			targetChannel = rest[0]
+			rest = rest[1:]
+		}
+	case "stable", "full":
+		if len(rest) > 0 {
+			return Version{}, fmt.Errorf("%q takes no second argument", action)
+		}
+		targetChannel = "stable"
+	default:
+		if contains(allowedChannels, action) {
+			if len(rest) > 0 {
+				return Version{}, errors.New("channel-only bump takes no second argument")
+			}
+			targetChannel = action
+			wasChannelOnly = true
+		} else {
+			return Version{}, fmt.Errorf("unknown argument %q", action)
+		}
+	}
+
+	if targetChannel == "" {
+		targetChannel = current.Channel
+	}
+	if err := validateChannel(targetChannel, allowedChannels); err != nil {
+		return Version{}, err
+	}
+	if current.Channel != "stable" && targetChannel == "stable" && action != "stable" && action != "full" {
+		return Version{}, fmt.Errorf("from prerelease channel %q, promote using 'stable' or 'full' only", current.Channel)
+	}
+	if part == "" && wasChannelOnly && current.Channel == "stable" && targetChannel != "stable" {
+		part = "patch"
+	}
+
+	next := current
+	oldBase := next.BaseString()
+	oldChannel := next.Channel
+	oldPre := next.Prerelease
+	if part != "" {
+		bumpVersion(&next, part)
+	}
+
+	if targetChannel == "stable" {
+		next.Channel = "stable"
+		next.Prerelease = 0
+	} else {
+		if next.BaseString() == oldBase && targetChannel == oldChannel && oldPre > 0 {
+			next.Prerelease = oldPre + 1
+		} else {
+			next.Prerelease = 1
+		}
+		next.Channel = targetChannel
+	}
+
+	if next.String() == currentFull {
+		return Version{}, fmt.Errorf("Version %s is already current; nothing to do.", next.String())
+	}
+
+	return next, nil
+}
+
+func resolveSetVersion(current Version, currentFull string, args []string, allowedChannels []string) (Version, error) {
+	if len(args) == 0 {
+		return Version{}, errors.New("'set' requires a version argument")
+	}
+	next, err := ParseVersion(args[0])
+	if err != nil {
+		return Version{}, err
+	}
+	if err := validateChannel(next.Channel, allowedChannels); err != nil {
+		return Version{}, err
+	}
+	if current.Channel != "stable" && next.Channel == "stable" {
+		return Version{}, fmt.Errorf("from prerelease channel %q, promote using 'stable' or 'full' only", current.Channel)
+	}
+	switch next.cmp(current) {
+	case 0:
+		return Version{}, fmt.Errorf("Version %s is already current; nothing to do.", next.String())
+	case -1:
+		return Version{}, fmt.Errorf("%s is lower than current %s", next.String(), currentFull)
+	}
+	return next, nil
+}
+
+func validateChannel(channel string, allowedChannels []string) error {
+	if channel == "" || channel == "stable" {
+		return nil
+	}
+	if contains(allowedChannels, channel) {
+		return nil
+	}
+	return fmt.Errorf("unknown channel %q", channel)
+}
+
+func bumpVersion(v *Version, part string) {
+	switch part {
+	case "major":
+		v.Major++
+		v.Minor = 0
+		v.Patch = 0
+	case "minor":
+		v.Minor++
+		v.Patch = 0
+	case "patch":
+		v.Patch++
+	default:
+		panic("unknown bump part: " + part)
+	}
+}
+
+func compareInt(left int, right int) int {
+	switch {
+	case left > right:
+		return 1
+	case left < right:
+		return -1
+	default:
+		return 0
+	}
+}
+
+func comparePrerelease(left string, right string) int {
+	values := []string{left, right}
+	sort.Slice(values, func(i int, j int) bool {
+		return semverLikeLess(values[i], values[j])
+	})
+	switch {
+	case left == right:
+		return 0
+	case values[len(values)-1] == left:
+		return 1
+	default:
+		return -1
+	}
+}
+
+func semverLikeLess(left string, right string) bool {
+	leftParts := strings.FieldsFunc(left, func(r rune) bool { return r == '.' || r == '-' })
+	rightParts := strings.FieldsFunc(right, func(r rune) bool { return r == '.' || r == '-' })
+	for i := 0; i < len(leftParts) && i < len(rightParts); i++ {
+		li, lerr := strconv.Atoi(leftParts[i])
+		ri, rerr := strconv.Atoi(rightParts[i])
+		switch {
+		case lerr == nil && rerr == nil:
+			if li != ri {
+				return li < ri
+			}
+		default:
+			if leftParts[i] != rightParts[i] {
+				return leftParts[i] < rightParts[i]
+			}
+		}
+	}
+	return len(leftParts) < len(rightParts)
+}

packages/release/internal/release/version_file.go

@@ -0,0 +1,112 @@
+package release
+
+import (
+	"bytes"
+	"fmt"
+	"os"
+	"strconv"
+	"strings"
+)
+
+type Metadata struct {
+	lines []string
+}
+
+func (m Metadata) Lines() []string {
+	return append([]string(nil), m.lines...)
+}
+
+func (m Metadata) Get(key string) string {
+	for _, line := range m.lines {
+		if strings.HasPrefix(line, key+"=") {
+			return strings.TrimPrefix(line, key+"=")
+		}
+	}
+	return ""
+}
+
+func (m *Metadata) Set(key string, value string) {
+	for i, line := range m.lines {
+		if strings.HasPrefix(line, key+"=") {
+			m.lines[i] = key + "=" + value
+			return
+		}
+	}
+	m.lines = append(m.lines, key+"="+value)
+}
+
+func (m *Metadata) Unset(key string) {
+	filtered := make([]string, 0, len(m.lines))
+	for _, line := range m.lines {
+		if strings.HasPrefix(line, key+"=") {
+			continue
+		}
+		filtered = append(filtered, line)
+	}
+	m.lines = filtered
+}
+
+type VersionFile struct {
+	Version  Version
+	Metadata Metadata
+}
+
+func (f VersionFile) Current() Version {
+	return f.Version
+}
+
+func ReadVersionFile(path string) (*VersionFile, error) {
+	data, err := os.ReadFile(path)
+	if err != nil {
+		return nil, err
+	}
+	text := strings.ReplaceAll(string(data), "\r\n", "\n")
+	lines := strings.Split(text, "\n")
+	if len(lines) < 3 {
+		return nil, fmt.Errorf("invalid VERSION file %q", path)
+	}
+
+	base := strings.TrimSpace(lines[0])
+	channel := strings.TrimSpace(lines[1])
+	preRaw := strings.TrimSpace(lines[2])
+	if channel == "" {
+		channel = "stable"
+	}
+
+	rawVersion := base
+	if channel != "stable" {
+		rawVersion = fmt.Sprintf("%s-%s.%s", base, channel, preRaw)
+	}
+	version, err := ParseVersion(rawVersion)
+	if err != nil {
+		return nil, err
+	}
+
+	metaLines := make([]string, 0, len(lines)-3)
+	for _, line := range lines[3:] {
+		if line == "" {
+			continue
+		}
+		metaLines = append(metaLines, line)
+	}
+	return &VersionFile{
+		Version:  version,
+		Metadata: Metadata{lines: metaLines},
+	}, nil
+}
+
+func (f *VersionFile) Write(path string) error {
+	channel := f.Version.Channel
+	pre := strconv.Itoa(f.Version.Prerelease)
+	if channel == "" || channel == "stable" {
+		channel = "stable"
+		pre = "0"
+	}
+
+	var buf bytes.Buffer
+	fmt.Fprintf(&buf, "%s\n%s\n%s\n", f.Version.BaseString(), channel, pre)
+	for _, line := range f.Metadata.lines {
+		fmt.Fprintln(&buf, line)
+	}
+	return os.WriteFile(path, buf.Bytes(), 0o644)
+}

packages/release/release.nix

@@ -1,4 +1,5 @@
 {
+  flake-parts,
   nixpkgs,
   treefmt-nix,
   lefthookNix,
@@ -7,6 +8,7 @@
 }:
 import ../repo-lib/lib.nix {
   inherit
+    flake-parts
     nixpkgs
     treefmt-nix
     lefthookNix

packages/release/release.sh

@@ -2,539 +2,18 @@
 
 set -euo pipefail
 
-ROOT_DIR="$(git rev-parse --show-toplevel)"
-GITLINT_FILE="$ROOT_DIR/.gitlint"
-START_HEAD=""
-CREATED_TAG=""
-VERSION_META_LINES=()
-VERSION_META_EXPORT_NAMES=()
-
-# ── logging ────────────────────────────────────────────────────────────────
-
-log() { echo "[release] $*" >&2; }
-
-usage() {
-	local cmd
-	cmd="$(basename "$0")"
-	printf '%s\n' \
-		"Usage:" \
-		"  ${cmd} [major|minor|patch] [stable|__CHANNEL_LIST__]" \
-		"  ${cmd} set <version>" \
-		"" \
-		"Bump types:" \
-		"  (none)            bump patch, keep current channel" \
-		"  major/minor/patch bump the given part, keep current channel" \
-		"  stable / full     remove prerelease suffix (only opt-in path to promote prerelease -> stable)" \
-		"  __CHANNEL_LIST__    switch channel (from stable, auto-bumps patch unless bump is specified)" \
-		"" \
-		"Safety rule:" \
-		"  If current version is prerelease (e.g. x.y.z-beta.N), promotion to stable is allowed only via 'stable' or 'full'." \
-		"  Commands like '${cmd} set x.y.z' or '${cmd} patch stable' are blocked from prerelease channels." \
-		"" \
-		"Examples:" \
-		"  ${cmd}                 # patch bump on current channel" \
-		"  ${cmd} minor           # minor bump on current channel" \
-		"  ${cmd} beta            # from stable: patch bump + beta.1" \
-		"  ${cmd} patch beta      # patch bump, switch to beta channel" \
-		"  ${cmd} rc              # switch to rc channel" \
-		"  ${cmd} stable          # promote prerelease to stable (opt-in)" \
-		"  ${cmd} set 1.2.3" \
-		"  ${cmd} set 1.2.3-beta.1"
-}
-
-# ── git ────────────────────────────────────────────────────────────────────
-
-require_clean_git() {
-	if ! git diff --quiet || ! git diff --cached --quiet; then
-		echo "Error: git working tree is not clean. Commit or stash changes first." >&2
-		exit 1
-	fi
-}
-
-revert_on_failure() {
-	local status=$?
-	if [[ -n $START_HEAD ]]; then
-		log "Release failed — reverting to $START_HEAD"
-		git reset --hard "$START_HEAD"
-	fi
-	if [[ -n $CREATED_TAG ]]; then
-		git tag -d "$CREATED_TAG" >/dev/null 2>&1 || true
-	fi
-	exit $status
-}
-
-# ── version parsing ────────────────────────────────────────────────────────
-
-parse_base_version() {
-	local v="$1"
-	if [[ ! $v =~ ^([0-9]+)\.([0-9]+)\.([0-9]+)$ ]]; then
-		echo "Error: invalid base version '$v' (expected x.y.z)" >&2
-		exit 1
-	fi
-	MAJOR="${BASH_REMATCH[1]}"
-	MINOR="${BASH_REMATCH[2]}"
-	PATCH="${BASH_REMATCH[3]}"
-}
-
-parse_full_version() {
-	local v="$1"
-	CHANNEL="stable"
-	PRERELEASE_NUM=""
-
-	if [[ $v =~ ^([0-9]+\.[0-9]+\.[0-9]+)-([a-zA-Z]+)\.([0-9]+)$ ]]; then
-		BASE_VERSION="${BASH_REMATCH[1]}"
-		CHANNEL="${BASH_REMATCH[2]}"
-		PRERELEASE_NUM="${BASH_REMATCH[3]}"
-	elif [[ $v =~ ^([0-9]+\.[0-9]+\.[0-9]+)$ ]]; then
-		BASE_VERSION="${BASH_REMATCH[1]}"
-	else
-		echo "Error: invalid version '$v' (expected x.y.z or x.y.z-channel.N)" >&2
-		exit 1
-	fi
-	parse_base_version "$BASE_VERSION"
-}
-
-validate_channel() {
-	local ch="$1"
-	[[ $ch == "stable" ]] && return 0
-	local valid_channels="__CHANNEL_LIST__"
-	for c in $valid_channels; do
-		[[ $ch == "$c" ]] && return 0
-	done
-	echo "Error: unknown channel '$ch'. Valid channels: stable $valid_channels" >&2
-	exit 1
-}
-
-version_cmp() {
-	# Returns: 0 if equal, 1 if v1 > v2, 2 if v1 < v2
-	# Stable > prerelease for same base version
-	local v1="$1" v2="$2"
-	[[ $v1 == "$v2" ]] && return 0
-
-	local base1="" pre1="" base2="" pre2=""
-	if [[ $v1 =~ ^([0-9]+\.[0-9]+\.[0-9]+)-(.+)$ ]]; then
-		base1="${BASH_REMATCH[1]}"
-		pre1="${BASH_REMATCH[2]}"
-	else
-		base1="$v1"
-	fi
-	if [[ $v2 =~ ^([0-9]+\.[0-9]+\.[0-9]+)-(.+)$ ]]; then
-		base2="${BASH_REMATCH[1]}"
-		pre2="${BASH_REMATCH[2]}"
-	else
-		base2="$v2"
-	fi
-
-	if [[ $base1 != "$base2" ]]; then
-		local highest_base
-		highest_base=$(printf '%s\n%s\n' "$base1" "$base2" | sort -V | tail -n1)
-		[[ $highest_base == "$base1" ]] && return 1 || return 2
-	fi
-
-	[[ -z $pre1 && -n $pre2 ]] && return 1 # stable > prerelease
-	[[ -n $pre1 && -z $pre2 ]] && return 2 # prerelease < stable
-	[[ -z $pre1 && -z $pre2 ]] && return 0 # both stable
-
-	local highest_pre
-	highest_pre=$(printf '%s\n%s\n' "$pre1" "$pre2" | sort -V | tail -n1)
-	[[ $highest_pre == "$pre1" ]] && return 1 || return 2
-}
-
-bump_base_version() {
-	case "$1" in
-	major)
-		MAJOR=$((MAJOR + 1))
-		MINOR=0
-		PATCH=0
-		;;
-	minor)
-		MINOR=$((MINOR + 1))
-		PATCH=0
-		;;
-	patch) PATCH=$((PATCH + 1)) ;;
-	*)
-		echo "Error: unknown bump part '$1'" >&2
-		exit 1
-		;;
-	esac
-	BASE_VERSION="${MAJOR}.${MINOR}.${PATCH}"
-}
-
-compute_full_version() {
-	if [[ $CHANNEL == "stable" || -z $CHANNEL ]]; then
-		FULL_VERSION="$BASE_VERSION"
-	else
-		FULL_VERSION="${BASE_VERSION}-${CHANNEL}.${PRERELEASE_NUM:-1}"
-	fi
-	FULL_TAG="v$FULL_VERSION"
-	export BASE_VERSION CHANNEL PRERELEASE_NUM FULL_VERSION FULL_TAG
-}
-
-meta_env_name() {
-	local key="$1"
-	key="${key//[^[:alnum:]]/_}"
-	key="$(printf '%s' "$key" | tr '[:lower:]' '[:upper:]')"
-	printf 'VERSION_META_%s\n' "$key"
-}
-
-clear_version_meta_exports() {
-	local export_name
-	for export_name in "${VERSION_META_EXPORT_NAMES[@]:-}"; do
-		unset "$export_name"
-	done
-	VERSION_META_EXPORT_NAMES=()
-}
-
-load_version_metadata() {
-	VERSION_META_LINES=()
-	[[ ! -f "$ROOT_DIR/VERSION" ]] && return 0
-
-	while IFS= read -r line || [[ -n $line ]]; do
-		VERSION_META_LINES+=("$line")
-	done < <(tail -n +4 "$ROOT_DIR/VERSION" 2>/dev/null || true)
-}
-
-export_version_metadata() {
-	clear_version_meta_exports
-
-	local line key value export_name
-	for line in "${VERSION_META_LINES[@]:-}"; do
-		[[ $line != *=* ]] && continue
-		key="${line%%=*}"
-		value="${line#*=}"
-		[[ -z $key ]] && continue
-		export_name="$(meta_env_name "$key")"
-		printf -v "$export_name" '%s' "$value"
-		export "${export_name?}=$value"
-		VERSION_META_EXPORT_NAMES+=("$export_name")
-	done
-}
-
-write_version_file() {
-	local channel_to_write="$1"
-	local n_to_write="$2"
-	{
-		printf '%s\n%s\n%s\n' "$BASE_VERSION" "$channel_to_write" "$n_to_write"
-		local line
-		for line in "${VERSION_META_LINES[@]:-}"; do
-			printf '%s\n' "$line"
-		done
-	} >"$ROOT_DIR/VERSION"
-}
-
-version_meta_get() {
-	local key="${1-}"
-	local line
-	for line in "${VERSION_META_LINES[@]:-}"; do
-		if [[ $line == "$key="* ]]; then
-			printf '%s\n' "${line#*=}"
-			return 0
-		fi
-	done
-	return 1
-}
-
-version_meta_set() {
-	local key="${1-}"
-	local value="${2-}"
-	[[ -z $key ]] && echo "Error: version_meta_set requires a key" >&2 && exit 1
-
-	local updated=0
-	local index
-	for index in "${!VERSION_META_LINES[@]}"; do
-		if [[ ${VERSION_META_LINES[index]} == "$key="* ]]; then
-			VERSION_META_LINES[index]="$key=$value"
-			updated=1
-			break
-		fi
-	done
-
-	if [[ $updated -eq 0 ]]; then
-		VERSION_META_LINES+=("$key=$value")
-	fi
-
-	export_version_metadata
-	version_meta_write
-}
-
-version_meta_unset() {
-	local key="${1-}"
-	[[ -z $key ]] && echo "Error: version_meta_unset requires a key" >&2 && exit 1
-
-	local filtered=()
-	local line
-	for line in "${VERSION_META_LINES[@]:-}"; do
-		[[ $line == "$key="* ]] && continue
-		filtered+=("$line")
-	done
-	VERSION_META_LINES=("${filtered[@]}")
-
-	export_version_metadata
-	version_meta_write
-}
-
-version_meta_write() {
-	local channel_to_write="$CHANNEL"
-	local n_to_write="${PRERELEASE_NUM:-1}"
-	if [[ $channel_to_write == "stable" || -z $channel_to_write ]]; then
-		channel_to_write="stable"
-		n_to_write="0"
-	fi
-	write_version_file "$channel_to_write" "$n_to_write"
-}
-
-# ── gitlint ────────────────────────────────────────────────────────────────
-
-get_gitlint_title_regex() {
-	[[ ! -f $GITLINT_FILE ]] && return 0
-	awk '
-    /^\[title-match-regex\]$/ { in_section=1; next }
-    /^\[/ { in_section=0 }
-    in_section && /^regex=/ { sub(/^regex=/, ""); print; exit }
-  ' "$GITLINT_FILE"
-}
-
-validate_commit_message() {
-	local msg="$1"
-	local regex
-	regex="$(get_gitlint_title_regex)"
-	if [[ -n $regex && ! $msg =~ $regex ]]; then
-		echo "Error: commit message does not match .gitlint title-match-regex" >&2
-		echo "Regex:   $regex" >&2
-		echo "Message: $msg" >&2
-		exit 1
-	fi
-}
-
-# ── version file generation ────────────────────────────────────────────────
-
-run_release_steps() {
-	:
-	__RELEASE_STEPS__
-}
-
-# ── version source (built-in) ──────────────────────────────────────────────
-
-# Initializes $ROOT_DIR/VERSION from git tags if it doesn't exist.
-# Must be called outside of any subshell so log output stays on stderr
-# and never contaminates the stdout of do_read_version.
-init_version_file() {
-	if [[ -f "$ROOT_DIR/VERSION" ]]; then
-		load_version_metadata
-		export_version_metadata
-		return 0
-	fi
-
-	local highest_tag=""
-	while IFS= read -r raw_tag; do
-		local tag="${raw_tag#v}"
-		[[ $tag =~ ^[0-9]+\.[0-9]+\.[0-9]+(-[a-zA-Z]+\.[0-9]+)?$ ]] || continue
-
-		if [[ -z $highest_tag ]]; then
-			highest_tag="$tag"
-			continue
-		fi
-
-		local cmp_status=0
-		version_cmp "$tag" "$highest_tag" || cmp_status=$?
-		[[ $cmp_status -eq 1 ]] && highest_tag="$tag"
-	done < <(git tag --list)
-
-	[[ -z $highest_tag ]] && highest_tag="0.0.1"
-
-	parse_full_version "$highest_tag"
-	local channel_to_write="$CHANNEL"
-	local n_to_write="${PRERELEASE_NUM:-1}"
-	if [[ $channel_to_write == "stable" || -z $channel_to_write ]]; then
-		channel_to_write="stable"
-		n_to_write="0"
-	fi
-
-	VERSION_META_LINES=()
-	write_version_file "$channel_to_write" "$n_to_write"
-	export_version_metadata
-	log "Initialized $ROOT_DIR/VERSION from highest tag: v$highest_tag"
-}
-
-do_read_version() {
-	load_version_metadata
-	export_version_metadata
-
-	local base_line channel_line n_line
-	base_line="$(sed -n '1p' "$ROOT_DIR/VERSION" | tr -d '\r')"
-	channel_line="$(sed -n '2p' "$ROOT_DIR/VERSION" | tr -d '\r')"
-	n_line="$(sed -n '3p' "$ROOT_DIR/VERSION" | tr -d '\r')"
-
-	if [[ -z $channel_line || $channel_line == "stable" ]]; then
-		printf '%s\n' "$base_line"
-	else
-		printf '%s-%s.%s\n' "$base_line" "$channel_line" "$n_line"
-	fi
-}
-
-do_write_version() {
-	local channel_to_write="$CHANNEL"
-	local n_to_write="${PRERELEASE_NUM:-1}"
-	if [[ $channel_to_write == "stable" || -z $channel_to_write ]]; then
-		channel_to_write="stable"
-		n_to_write="0"
-	fi
-	write_version_file "$channel_to_write" "$n_to_write"
-	export_version_metadata
-}
-
-# ── user-provided hook ─────────────────────────────────────────────────────
-
-do_post_version() {
-	:
+REPO_LIB_RELEASE_ROOT_DIR="$(git rev-parse --show-toplevel)"
+export REPO_LIB_RELEASE_ROOT_DIR
+export REPO_LIB_RELEASE_CHANNELS='__CHANNEL_LIST__'
+REPO_LIB_RELEASE_STEPS_JSON="$(cat <<'EOF'
+__RELEASE_STEPS_JSON__
+EOF
+)"
+export REPO_LIB_RELEASE_STEPS_JSON
+REPO_LIB_RELEASE_POST_VERSION="$(cat <<'EOF'
 __POST_VERSION__
-}
+EOF
+)"
+export REPO_LIB_RELEASE_POST_VERSION
 
-# ── main ───────────────────────────────────────────────────────────────────
-
-main() {
-	[[ ${1-} == "-h" || ${1-} == "--help" ]] && usage && exit 0
-
-	require_clean_git
-	START_HEAD="$(git rev-parse HEAD)"
-	trap revert_on_failure ERR
-
-	# Initialize VERSION file outside any subshell so log lines never
-	# bleed into the stdout capture below.
-	init_version_file
-
-	local raw_version
-	raw_version="$(do_read_version | grep -E '^[0-9]+\.[0-9]+\.[0-9]+(-[a-zA-Z]+\.[0-9]+)?$' | tail -n1)"
-	if [[ -z $raw_version ]]; then
-		echo "Error: could not determine current version from VERSION source" >&2
-		exit 1
-	fi
-	parse_full_version "$raw_version"
-	compute_full_version
-	local current_full="$FULL_VERSION"
-
-	log "Current: base=$BASE_VERSION channel=$CHANNEL pre=${PRERELEASE_NUM:-}"
-
-	local action="${1-}"
-	shift || true
-
-	if [[ $action == "set" ]]; then
-		local newv="${1-}"
-		local current_channel="$CHANNEL"
-		[[ -z $newv ]] && echo "Error: 'set' requires a version argument" >&2 && exit 1
-		parse_full_version "$newv"
-		validate_channel "$CHANNEL"
-		if [[ $current_channel != "stable" && $CHANNEL == "stable" ]]; then
-			echo "Error: from prerelease channel '$current_channel', promote using 'stable' or 'full' only" >&2
-			exit 1
-		fi
-		compute_full_version
-		local cmp_status=0
-		version_cmp "$FULL_VERSION" "$current_full" || cmp_status=$?
-		case $cmp_status in
-		0)
-			echo "Version $FULL_VERSION is already current; nothing to do." >&2
-			exit 1
-			;;
-		2)
-			echo "Error: $FULL_VERSION is lower than current $current_full" >&2
-			exit 1
-			;;
-		esac
-
-	else
-		local part="" target_channel="" was_channel_only=0
-
-		case "$action" in
-		"") part="patch" ;;
-		major | minor | patch)
-			part="$action"
-			target_channel="${1-}"
-			;;
-		stable | full)
-			[[ -n ${1-} ]] && echo "Error: '$action' takes no second argument" >&2 && usage && exit 1
-			target_channel="stable"
-			;;
-		*)
-			# check if action is a valid channel
-			local is_channel=0
-			for c in __CHANNEL_LIST__; do
-				[[ $action == "$c" ]] && is_channel=1 && break
-			done
-			if [[ $is_channel == 1 ]]; then
-				[[ -n ${1-} ]] && echo "Error: channel-only bump takes no second argument" >&2 && usage && exit 1
-				target_channel="$action"
-				was_channel_only=1
-			else
-				echo "Error: unknown argument '$action'" >&2
-				usage
-				exit 1
-			fi
-			;;
-		esac
-
-		[[ -z $target_channel ]] && target_channel="$CHANNEL"
-		[[ $target_channel == "full" ]] && target_channel="stable"
-		validate_channel "$target_channel"
-		if [[ $CHANNEL != "stable" && $target_channel == "stable" && $action != "stable" && $action != "full" ]]; then
-			echo "Error: from prerelease channel '$CHANNEL', promote using 'stable' or 'full' only" >&2
-			exit 1
-		fi
-
-		if [[ -z $part && $was_channel_only -eq 1 && $CHANNEL == "stable" && $target_channel != "stable" ]]; then
-			part="patch"
-		fi
-
-		local old_base="$BASE_VERSION" old_channel="$CHANNEL" old_pre="$PRERELEASE_NUM"
-		[[ -n $part ]] && bump_base_version "$part"
-
-		if [[ $target_channel == "stable" ]]; then
-			CHANNEL="stable"
-			PRERELEASE_NUM=""
-		else
-			if [[ $BASE_VERSION == "$old_base" && $target_channel == "$old_channel" && -n $old_pre ]]; then
-				PRERELEASE_NUM=$((old_pre + 1))
-			else
-				PRERELEASE_NUM=1
-			fi
-			CHANNEL="$target_channel"
-		fi
-	fi
-
-	compute_full_version
-	if [[ $FULL_VERSION == "$current_full" ]]; then
-		echo "Version $FULL_VERSION is already current; nothing to do." >&2
-		exit 1
-	fi
-	log "Releasing $FULL_VERSION"
-
-	do_write_version
-	log "Updated version source"
-
-	run_release_steps
-	log "Release steps done"
-
-	do_post_version
-	log "Post-version hook done"
-
-	(cd "$ROOT_DIR" && nix fmt)
-	log "Formatted files"
-
-	git add -A
-	local commit_msg="chore(release): v$FULL_VERSION"
-	validate_commit_message "$commit_msg"
-	git commit -m "$commit_msg"
-	log "Created commit"
-
-	git tag "$FULL_TAG"
-	CREATED_TAG="$FULL_TAG"
-	log "Tagged $FULL_TAG"
-
-	git push
-	git push --tags
-	log "Done — released $FULL_TAG"
-
-	trap - ERR
-}
-
-main "$@"
+exec __RELEASE_RUNNER__ "$@"

packages/repo-lib/lib.nix

@@ -1,4 +1,5 @@
 {
+  flake-parts,
   nixpkgs,
   treefmt-nix,
   lefthookNix,
@@ -6,58 +7,12 @@
   shellHookTemplatePath,
 }:
 let
-  lib = nixpkgs.lib;
-
-  supportedSystems = [
-    "x86_64-linux"
-    "aarch64-linux"
-    "x86_64-darwin"
-    "aarch64-darwin"
-  ];
-
-  defaultReleaseChannels = [
-    "alpha"
-    "beta"
-    "rc"
-    "internal"
-  ];
-
-  importPkgs = nixpkgsInput: system: import nixpkgsInput { inherit system; };
-
-  duplicateStrings =
-    names:
-    lib.unique (
-      builtins.filter (
-        name: builtins.length (builtins.filter (candidate: candidate == name) names) > 1
-      ) names
-    );
-
-  mergeUniqueAttrs =
-    label: left: right:
-    let
-      overlap = builtins.attrNames (lib.intersectAttrs left right);
-    in
-    if overlap != [ ] then
-      throw "repo-lib: duplicate ${label}: ${lib.concatStringsSep ", " overlap}"
-    else
-      left // right;
-
-  sanitizeName = name: lib.strings.sanitizeDerivationName name;
-
-  defaultShellBanner = {
-    style = "simple";
-    icon = "🚀";
-    title = "Dev shell ready";
-    titleColor = "GREEN";
-    subtitle = "";
-    subtitleColor = "GRAY";
-    borderColor = "BLUE";
-  };
-
+  defaults = import ./lib/defaults.nix { };
+  common = import ./lib/common.nix { inherit nixpkgs; };
   normalizeShellBanner =
     rawBanner:
     let
-      banner = defaultShellBanner // rawBanner;
+      banner = defaults.defaultShellBanner // rawBanner;
     in
     if
       !(builtins.elem banner.style [
@@ -68,812 +23,78 @@ let
       throw "repo-lib: config.shell.banner.style must be one of simple or pretty"
     else
       banner;
-
-  normalizeStrictTool =
-    pkgs: tool:
-    let
-      version = {
-        args = [ "--version" ];
-        match = null;
-        regex = null;
-        group = 0;
-        line = 1;
-      }
-      // (tool.version or { });
-      banner = {
-        color = "YELLOW";
-        icon = null;
-        iconColor = null;
-      }
-      // (tool.banner or { });
-      executable =
-        if tool ? command && tool.command != null then
-          tool.command
-        else if tool ? exe && tool.exe != null then
-          "${lib.getExe' tool.package tool.exe}"
-        else
-          "${lib.getExe tool.package}";
-    in
-    if !(tool ? command && tool.command != null) && !(tool ? package) then
-      throw "repo-lib: tool '${tool.name or "<unnamed>"}' is missing 'package' or 'command'"
-    else
-      {
-        kind = "strict";
-        inherit executable version banner;
-        name = tool.name;
-        package = tool.package or null;
-        required = tool.required or true;
+  toolsModule = import ./lib/tools.nix {
+    lib = common.lib;
   };
-
-  normalizeLegacyTool =
-    pkgs: tool:
-    if tool ? package then
-      normalizeStrictTool pkgs tool
-    else
-      {
-        kind = "legacy";
-        name = tool.name;
-        command = tool.bin;
-        versionCommand = tool.versionCmd or "--version";
-        banner = {
-          color = tool.color or "YELLOW";
-          icon = tool.icon or null;
-          iconColor = tool.iconColor or null;
+  hooksModule = import ./lib/hooks.nix {
+    inherit (common) lib sanitizeName;
   };
-        required = tool.required or false;
-      };
-
-  checkToLefthookConfig =
-    pkgs: name: rawCheck:
-    let
-      check = {
-        stage = "pre-commit";
-        passFilenames = false;
-        runtimeInputs = [ ];
-      }
-      // rawCheck;
-      wrapperName = "repo-lib-check-${sanitizeName name}";
-      wrapper = pkgs.writeShellApplication {
-        name = wrapperName;
-        runtimeInputs = check.runtimeInputs;
-        text = ''
-          set -euo pipefail
-          ${check.command}
-        '';
-      };
-    in
-    if !(check ? command) then
-      throw "repo-lib: check '${name}' is missing 'command'"
-    else if
-      !(builtins.elem check.stage [
-        "pre-commit"
-        "pre-push"
-      ])
-    then
-      throw "repo-lib: check '${name}' has unsupported stage '${check.stage}'"
-    else
-      lib.setAttrByPath [ check.stage "commands" name ] {
-        run = "${wrapper}/bin/${wrapperName}${hookStageFileArgs check.stage check.passFilenames}";
-      };
-
-  normalizeLefthookConfig =
-    label: raw: if builtins.isAttrs raw then raw else throw "repo-lib: ${label} must be an attrset";
-
-  normalizeHookStage =
-    hookName: stage:
-    if
-      builtins.elem stage [
-        "pre-commit"
-        "pre-push"
-        "commit-msg"
-      ]
-    then
-      stage
-    else
-      throw "repo-lib: hook '${hookName}' has unsupported stage '${stage}' for lefthook";
-
-  hookStageFileArgs =
-    stage: passFilenames:
-    if !passFilenames then
-      ""
-    else if stage == "pre-commit" then
-      " {staged_files}"
-    else if stage == "pre-push" then
-      " {push_files}"
-    else if stage == "commit-msg" then
-      " {1}"
-    else
-      throw "repo-lib: unsupported lefthook stage '${stage}'";
-
-  hookToLefthookConfig =
-    name: hook:
-    let
-      supportedFields = [
-        "description"
-        "enable"
-        "entry"
-        "name"
-        "package"
-        "pass_filenames"
-        "stages"
-      ];
-      unsupportedFields = builtins.filter (field: !(builtins.elem field supportedFields)) (
-        builtins.attrNames hook
-      );
-      stages = builtins.map (stage: normalizeHookStage name stage) (hook.stages or [ "pre-commit" ]);
-      passFilenames = hook.pass_filenames or false;
-    in
-    if unsupportedFields != [ ] then
-      throw ''
-        repo-lib: hook '${name}' uses unsupported fields for lefthook: ${lib.concatStringsSep ", " unsupportedFields}
-      ''
-    else if !(hook ? entry) then
-      throw "repo-lib: hook '${name}' is missing 'entry'"
-    else
-      lib.foldl' lib.recursiveUpdate { } (
-        builtins.map (
-          stage:
-          lib.setAttrByPath [ stage "commands" name ] {
-            run = "${hook.entry}${hookStageFileArgs stage passFilenames}";
-          }
-        ) stages
-      );
-
-  parallelHookStageConfig =
-    stage:
-    if
-      builtins.elem stage [
-        "pre-commit"
-        "pre-push"
-      ]
-    then
-      lib.setAttrByPath [ stage "parallel" ] true
-    else
-      { };
-
-  normalizeReleaseStep =
-    step:
-    if step ? writeFile then
-      {
-        kind = "writeFile";
-        path = step.writeFile.path;
-        text = step.writeFile.text;
-        runtimeInputs = [ ];
-      }
-    else if step ? replace then
-      {
-        kind = "replace";
-        path = step.replace.path;
-        regex = step.replace.regex;
-        replacement = step.replace.replacement;
-        runtimeInputs = [ ];
-      }
-    else if step ? run && builtins.isAttrs step.run then
-      {
-        kind = "run";
-        script = step.run.script;
-        runtimeInputs = step.run.runtimeInputs or [ ];
-      }
-    else if step ? run then
-      {
-        kind = "run";
-        script = step.run;
-        runtimeInputs = [ ];
-      }
-    else if step ? file then
-      {
-        kind = "writeFile";
-        path = step.file;
-        text = step.content;
-        runtimeInputs = [ ];
-      }
-    else
-      throw "repo-lib: release step must contain one of writeFile, replace, or run";
-
-  releaseStepScript =
-    step:
-    if step.kind == "writeFile" then
-      ''
-        target_path="$ROOT_DIR/${step.path}"
-        mkdir -p "$(dirname "$target_path")"
-        cat >"$target_path" << NIXEOF
-        ${step.text}
-        NIXEOF
-        log "Generated version file: ${step.path}"
-      ''
-    else if step.kind == "replace" then
-      ''
-        target_path="$ROOT_DIR/${step.path}"
-        REPO_LIB_STEP_REGEX=$(cat <<'NIXEOF'
-        ${step.regex}
-        NIXEOF
-        )
-        REPO_LIB_STEP_REPLACEMENT=$(cat <<NIXEOF
-        ${step.replacement}
-        NIXEOF
-        )
-        export REPO_LIB_STEP_REGEX REPO_LIB_STEP_REPLACEMENT
-        perl - "$target_path" <<'REPO_LIB_PERL_REPLACE'
-        use strict;
-        use warnings;
-
-        my $path = shift @ARGV;
-        my $regex_src = $ENV{"REPO_LIB_STEP_REGEX"} // q{};
-        my $template = $ENV{"REPO_LIB_STEP_REPLACEMENT"} // q{};
-
-        open my $in, q{<}, $path or die "failed to open $path: $!";
-        local $/ = undef;
-        my $content = <$in>;
-        close $in;
-
-        my $regex = qr/$regex_src/ms;
-        $content =~ s{$regex}{
-          my @cap = map { defined $_ ? $_ : q{} } ($1, $2, $3, $4, $5, $6, $7, $8, $9);
-          my $result = $template;
-          $result =~ s{\\([1-9])}{$cap[$1 - 1]}ge;
-          $result;
-        }gems;
-
-        open my $out, q{>}, $path or die "failed to open $path for write: $!";
-        print {$out} $content;
-        close $out;
-        REPO_LIB_PERL_REPLACE
-        log "Updated ${step.path}"
-      ''
-    else
-      ''
-        ${step.script}
-      '';
-
-  normalizeReleaseConfig =
-    raw:
-    let
-      hasLegacySteps = raw ? release;
-      hasStructuredSteps = raw ? steps;
-      steps =
-        if hasLegacySteps && hasStructuredSteps then
-          throw "repo-lib: pass either 'release' or 'steps' to mkRelease, not both"
-        else if hasStructuredSteps then
-          builtins.map normalizeReleaseStep raw.steps
-        else if hasLegacySteps then
-          builtins.map normalizeReleaseStep raw.release
-        else
-          [ ];
-    in
-    {
-      postVersion = raw.postVersion or "";
-      channels = raw.channels or defaultReleaseChannels;
-      runtimeInputs = (raw.runtimeInputs or [ ]) ++ (raw.extraRuntimeInputs or [ ]);
-      steps = steps;
-    };
-
-  buildShellHook =
-    {
-      hooksShellHook,
-      shellEnvScript,
-      bootstrap,
-      shellBannerScript,
-      extraShellText,
-      toolLabelWidth,
-    }:
-    let
-      template = builtins.readFile shellHookTemplatePath;
-    in
-    builtins.replaceStrings
-      [
-        "@HOOKS_SHELL_HOOK@"
-        "@TOOL_LABEL_WIDTH@"
-        "@SHELL_ENV_SCRIPT@"
-        "@BOOTSTRAP@"
-        "@SHELL_BANNER_SCRIPT@"
-        "@EXTRA_SHELL_TEXT@"
-      ]
-      [
-        hooksShellHook
-        (toString toolLabelWidth)
-        shellEnvScript
-        bootstrap
-        shellBannerScript
-        extraShellText
-      ]
-      template;
-
-  buildShellArtifacts =
-    {
-      pkgs,
-      system,
-      src,
-      includeStandardPackages ? true,
-      formatting,
-      tools ? [ ],
-      shellConfig ? {
-        env = { };
-        extraShellText = "";
-        bootstrap = "";
-        banner = defaultShellBanner;
-      },
-      checkSpecs ? { },
-      rawHookEntries ? { },
-      lefthookConfig ? { },
-      extraPackages ? [ ],
-    }:
-    let
-      standardPackages = with pkgs; [
-        nixfmt
-        gitlint
-        gitleaks
-        shfmt
-      ];
-      toolPackages = lib.filter (pkg: pkg != null) (builtins.map (tool: tool.package or null) tools);
-      selectedStandardPackages = lib.optionals includeStandardPackages standardPackages;
-
-      treefmtEval = treefmt-nix.lib.evalModule pkgs {
-        projectRootFile = "flake.nix";
-        programs = {
-          nixfmt.enable = true;
-        }
-        // formatting.programs;
-        settings.formatter = { } // formatting.settings;
-      };
-      treefmtWrapper = treefmtEval.config.build.wrapper;
-      lefthookBinWrapper = pkgs.writeShellScript "lefthook-dumb-term" ''
-        exec env TERM=dumb ${lib.getExe pkgs.lefthook} "$@"
-      '';
-
-      normalizedLefthookConfig = normalizeLefthookConfig "lefthook config" lefthookConfig;
-      lefthookCheck = lefthookNix.lib.${system}.run {
-        inherit src;
-        config = lib.foldl' lib.recursiveUpdate { } (
-          [
-            {
-              output = [
-                "failure"
-                "summary"
-              ];
-            }
-            (parallelHookStageConfig "pre-commit")
-            (parallelHookStageConfig "pre-push")
-            (lib.setAttrByPath [ "pre-commit" "commands" "treefmt" ] {
-              run = "${treefmtWrapper}/bin/treefmt --no-cache {staged_files}";
-              stage_fixed = true;
-            })
-            (lib.setAttrByPath [ "pre-commit" "commands" "gitleaks" ] {
-              run = "${pkgs.gitleaks}/bin/gitleaks protect --staged";
-            })
-            (lib.setAttrByPath [ "commit-msg" "commands" "gitlint" ] {
-              run = "${pkgs.gitlint}/bin/gitlint --staged --msg-filename {1}";
-            })
-          ]
-          ++ lib.mapAttrsToList (name: check: checkToLefthookConfig pkgs name check) checkSpecs
-          ++ lib.mapAttrsToList hookToLefthookConfig rawHookEntries
-          ++ [ normalizedLefthookConfig ]
-        );
-      };
-      selectedCheckOutputs = {
-        formatting-check = treefmtEval.config.build.check src;
-        hook-check = lefthookCheck;
-        lefthook-check = lefthookCheck;
-      };
-
-      toolNames = builtins.map (tool: tool.name) tools;
-      toolNameWidth =
-        if toolNames == [ ] then
-          0
-        else
-          builtins.foldl' (maxWidth: name: lib.max maxWidth (builtins.stringLength name)) 0 toolNames;
-      toolLabelWidth = toolNameWidth + 1;
-
-      shellEnvScript = lib.concatStringsSep "\n" (
-        lib.mapAttrsToList (
-          name: value: "export ${name}=${lib.escapeShellArg (toString value)}"
-        ) shellConfig.env
-      );
-
-      banner = normalizeShellBanner (shellConfig.banner or { });
-
-      shellBannerScript =
-        if banner.style == "pretty" then
-          ''
-            repo_lib_print_pretty_header \
-              ${lib.escapeShellArg banner.borderColor} \
-              ${lib.escapeShellArg banner.titleColor} \
-              ${lib.escapeShellArg banner.icon} \
-              ${lib.escapeShellArg banner.title} \
-              ${lib.escapeShellArg banner.subtitleColor} \
-              ${lib.escapeShellArg banner.subtitle}
-          ''
-          + lib.concatMapStrings (
-            tool:
-            if tool.kind == "strict" then
-              ''
-                repo_lib_print_pretty_tool \
-                  ${lib.escapeShellArg banner.borderColor} \
-                  ${lib.escapeShellArg tool.name} \
-                  ${lib.escapeShellArg tool.banner.color} \
-                  ${lib.escapeShellArg (if tool.banner.icon == null then "" else tool.banner.icon)} \
-                  ${lib.escapeShellArg (if tool.banner.iconColor == null then "" else tool.banner.iconColor)} \
-                  ${lib.escapeShellArg (if tool.required then "1" else "0")} \
-                  ${lib.escapeShellArg (toString tool.version.line)} \
-                  ${lib.escapeShellArg (toString tool.version.group)} \
-                  ${lib.escapeShellArg (if tool.version.regex == null then "" else tool.version.regex)} \
-                  ${lib.escapeShellArg (if tool.version.match == null then "" else tool.version.match)} \
-                  ${lib.escapeShellArg tool.executable} \
-                  ${lib.escapeShellArgs tool.version.args}
-              ''
-            else
-              ''
-                repo_lib_print_pretty_legacy_tool \
-                  ${lib.escapeShellArg banner.borderColor} \
-                  ${lib.escapeShellArg tool.name} \
-                  ${lib.escapeShellArg tool.banner.color} \
-                  ${lib.escapeShellArg (if tool.banner.icon == null then "" else tool.banner.icon)} \
-                  ${lib.escapeShellArg (if tool.banner.iconColor == null then "" else tool.banner.iconColor)} \
-                  ${lib.escapeShellArg (if tool.required then "1" else "0")} \
-                  ${lib.escapeShellArg tool.command} \
-                  ${lib.escapeShellArg tool.versionCommand}
-              ''
-          ) tools
-          + ''
-            repo_lib_print_pretty_footer \
-              ${lib.escapeShellArg banner.borderColor}
-          ''
-        else
-          ''
-            repo_lib_print_simple_header \
-              ${lib.escapeShellArg banner.titleColor} \
-              ${lib.escapeShellArg banner.icon} \
-              ${lib.escapeShellArg banner.title} \
-              ${lib.escapeShellArg banner.subtitleColor} \
-              ${lib.escapeShellArg banner.subtitle}
-          ''
-          + lib.concatMapStrings (
-            tool:
-            if tool.kind == "strict" then
-              ''
-                repo_lib_print_simple_tool \
-                  ${lib.escapeShellArg tool.name} \
-                  ${lib.escapeShellArg tool.banner.color} \
-                  ${lib.escapeShellArg (if tool.banner.icon == null then "" else tool.banner.icon)} \
-                  ${lib.escapeShellArg (if tool.banner.iconColor == null then "" else tool.banner.iconColor)} \
-                  ${lib.escapeShellArg (if tool.required then "1" else "0")} \
-                  ${lib.escapeShellArg (toString tool.version.line)} \
-                  ${lib.escapeShellArg (toString tool.version.group)} \
-                  ${lib.escapeShellArg (if tool.version.regex == null then "" else tool.version.regex)} \
-                  ${lib.escapeShellArg (if tool.version.match == null then "" else tool.version.match)} \
-                  ${lib.escapeShellArg tool.executable} \
-                  ${lib.escapeShellArgs tool.version.args}
-              ''
-            else
-              ''
-                repo_lib_print_simple_legacy_tool \
-                  ${lib.escapeShellArg tool.name} \
-                  ${lib.escapeShellArg tool.banner.color} \
-                  ${lib.escapeShellArg (if tool.banner.icon == null then "" else tool.banner.icon)} \
-                  ${lib.escapeShellArg (if tool.banner.iconColor == null then "" else tool.banner.iconColor)} \
-                  ${lib.escapeShellArg (if tool.required then "1" else "0")} \
-                  ${lib.escapeShellArg tool.command} \
-                  ${lib.escapeShellArg tool.versionCommand}
-              ''
-          ) tools
-          + ''
-            printf "\n"
-          '';
-    in
-    {
-      checks = selectedCheckOutputs;
-      formatter = treefmtWrapper;
-      shell = pkgs.mkShell {
-        LEFTHOOK_BIN = builtins.toString lefthookBinWrapper;
-        packages = lib.unique (
-          selectedStandardPackages
-          ++ extraPackages
-          ++ toolPackages
-          ++ [
-            pkgs.lefthook
-            treefmtWrapper
-          ]
-        );
-        shellHook = buildShellHook {
-          hooksShellHook = lefthookCheck.shellHook;
-          inherit toolLabelWidth shellEnvScript shellBannerScript;
-          bootstrap = shellConfig.bootstrap;
-          extraShellText = shellConfig.extraShellText;
-        };
-      };
-    }
-    // selectedCheckOutputs;
-in
-rec {
-  systems = {
-    default = supportedSystems;
-  };
-
-  tools = rec {
-    fromPackage =
-      {
-        name,
-        package,
-        exe ? null,
-        version ? { },
-        banner ? { },
-        required ? true,
-      }:
-      {
+  shellModule = import ./lib/shell.nix {
+    inherit (common)
+      lib
+      ;
     inherit
-          name
-          package
-          exe
-          version
-          banner
-          required
+      treefmt-nix
+      lefthookNix
+      shellHookTemplatePath
+      ;
+    inherit (defaults)
+      defaultShellBanner
+      ;
+    inherit normalizeShellBanner;
+    inherit (hooksModule)
+      normalizeLefthookConfig
+      parallelHookStageConfig
+      checkToLefthookConfig
+      hookToLefthookConfig
       ;
   };
-
-    fromCommand =
-      {
-        name,
-        command,
-        version ? { },
-        banner ? { },
-        required ? true,
-      }:
-      {
+  releaseModule = import ./lib/release.nix {
+    inherit (common)
+      lib
+      importPkgs
+      ;
     inherit
-          name
-          command
-          version
-          banner
-          required
+      nixpkgs
+      releaseScriptPath
+      ;
+    inherit (defaults)
+      defaultReleaseChannels
       ;
   };
-
-    simple =
-      name: package: args:
-      fromPackage {
-        inherit name package;
-        version.args = args;
-      };
-  };
-
-  normalizeRepoConfig =
-    rawConfig:
-    let
-      merged = lib.recursiveUpdate {
-        includeStandardPackages = true;
-        shell = {
-          env = { };
-          extraShellText = "";
-          allowImpureBootstrap = false;
-          bootstrap = "";
-          banner = { };
-        };
-        formatting = {
-          programs = { };
-          settings = { };
-        };
-        checks = { };
-        lefthook = { };
-        release = null;
-      } rawConfig;
-      release =
-        if merged.release == null then
-          null
-        else
-          {
-            channels = defaultReleaseChannels;
-            steps = [ ];
-            postVersion = "";
-            runtimeInputs = [ ];
-          }
-          // merged.release;
-    in
-    if merged.shell.bootstrap != "" && !merged.shell.allowImpureBootstrap then
-      throw "repo-lib: config.shell.bootstrap requires config.shell.allowImpureBootstrap = true"
-    else
-      merged
-      // {
-        inherit release;
-        shell = merged.shell // {
-          banner = normalizeShellBanner merged.shell.banner;
-        };
-      };
-
-  mkDevShell =
-    {
-      system,
-      src ? ./.,
-      nixpkgsInput ? nixpkgs,
-      extraPackages ? [ ],
-      preToolHook ? "",
-      extraShellHook ? "",
-      additionalHooks ? { },
-      lefthook ? { },
-      tools ? [ ],
-      includeStandardPackages ? true,
-      formatters ? { },
-      formatterSettings ? { },
-      features ? { },
-    }:
-    let
-      pkgs = importPkgs nixpkgsInput system;
-      oxfmtEnabled = features.oxfmt or false;
-      legacyTools = builtins.map (tool: normalizeLegacyTool pkgs tool) tools;
-      duplicateToolNames = duplicateStrings (builtins.map (tool: tool.name) legacyTools);
-      normalizedFormatting = {
-        programs =
-          (lib.optionalAttrs oxfmtEnabled {
-            oxfmt.enable = true;
-          })
-          // formatters;
-        settings = formatterSettings;
-      };
-      shellConfig = {
-        env = { };
-        extraShellText = extraShellHook;
-        allowImpureBootstrap = true;
-        bootstrap = preToolHook;
-        banner = defaultShellBanner;
-      };
-    in
-    if duplicateToolNames != [ ] then
-      throw "repo-lib: duplicate tool names: ${lib.concatStringsSep ", " duplicateToolNames}"
-    else
-      buildShellArtifacts {
+  repoModule = import ./lib/repo.nix {
     inherit
-          pkgs
-          system
-          src
-          includeStandardPackages
+      flake-parts
+      nixpkgs
       ;
-        formatting = normalizedFormatting;
-        rawHookEntries = additionalHooks;
-        lefthookConfig = lefthook;
-        shellConfig = shellConfig;
-        tools = legacyTools;
-        extraPackages =
-          extraPackages
-          ++ lib.optionals oxfmtEnabled [
-            pkgs.oxfmt
-            pkgs.oxlint
-          ];
-      };
-
-  mkRelease =
-    {
-      system,
-      nixpkgsInput ? nixpkgs,
-      ...
-    }@rawArgs:
-    let
-      pkgs = importPkgs nixpkgsInput system;
-      release = normalizeReleaseConfig rawArgs;
-      channelList = lib.concatStringsSep " " release.channels;
-      releaseStepsScript = lib.concatMapStrings releaseStepScript release.steps;
-      script =
-        builtins.replaceStrings
-          [
-            "__CHANNEL_LIST__"
-            "__RELEASE_STEPS__"
-            "__POST_VERSION__"
-          ]
-          [
-            channelList
-            releaseStepsScript
-            release.postVersion
-          ]
-          (builtins.readFile releaseScriptPath);
-    in
-    pkgs.writeShellApplication {
-      name = "release";
-      runtimeInputs =
-        with pkgs;
-        [
-          git
-          gnugrep
-          gawk
-          gnused
-          coreutils
-          perl
-        ]
-        ++ release.runtimeInputs
-        ++ lib.concatMap (step: step.runtimeInputs or [ ]) release.steps;
-      text = script;
-    };
-
-  mkRepo =
-    {
-      self,
-      nixpkgs,
-      src ? ./.,
-      systems ? supportedSystems,
-      config ? { },
-      perSystem ? (
-        {
-          pkgs,
-          system,
-          lib,
-          config,
-        }:
-        { }
-      ),
-    }:
-    let
-      normalizedConfig = normalizeRepoConfig config;
-      systemResults = lib.genAttrs systems (
-        system:
-        let
-          pkgs = importPkgs nixpkgs system;
-          perSystemResult = {
-            tools = [ ];
-            shell = { };
-            checks = { };
-            lefthook = { };
-            packages = { };
-            apps = { };
-          }
-          // perSystem {
-            inherit pkgs system;
-            lib = nixpkgs.lib;
-            config = normalizedConfig;
-          };
-
-          strictTools = builtins.map (tool: normalizeStrictTool pkgs tool) perSystemResult.tools;
-          duplicateToolNames = duplicateStrings (builtins.map (tool: tool.name) strictTools);
-          mergedChecks = mergeUniqueAttrs "check" normalizedConfig.checks perSystemResult.checks;
-          mergedLefthookConfig =
-            lib.recursiveUpdate (normalizeLefthookConfig "config.lefthook" normalizedConfig.lefthook)
-              (normalizeLefthookConfig "perSystem.lefthook" (perSystemResult.lefthook or { }));
-          shellConfig = lib.recursiveUpdate normalizedConfig.shell (perSystemResult.shell or { });
-          env =
-            if duplicateToolNames != [ ] then
-              throw "repo-lib: duplicate tool names: ${lib.concatStringsSep ", " duplicateToolNames}"
-            else
-              buildShellArtifacts {
-                inherit
-                  pkgs
-                  system
-                  src
+    inherit (common)
+      lib
+      importPkgs
+      duplicateStrings
+      mergeUniqueAttrs
+      ;
+    inherit (defaults)
+      supportedSystems
+      defaultReleaseChannels
+      ;
+    inherit (toolsModule)
+      normalizeStrictTool
+      ;
+    inherit (hooksModule)
+      normalizeLefthookConfig
+      ;
+    inherit normalizeShellBanner;
+    inherit (shellModule)
+      buildShellArtifacts
+      ;
+    inherit (releaseModule)
+      mkRelease
       ;
-                includeStandardPackages = normalizedConfig.includeStandardPackages;
-                formatting = normalizedConfig.formatting;
-                tools = strictTools;
-                checkSpecs = mergedChecks;
-                lefthookConfig = mergedLefthookConfig;
-                shellConfig = shellConfig;
-                extraPackages = perSystemResult.shell.packages or [ ];
-              };
-
-          releasePackages =
-            if normalizedConfig.release == null then
-              { }
-            else
-              {
-                release = mkRelease {
-                  inherit system;
-                  nixpkgsInput = nixpkgs;
-                  channels = normalizedConfig.release.channels;
-                  steps = normalizedConfig.release.steps;
-                  postVersion = normalizedConfig.release.postVersion;
-                  runtimeInputs = normalizedConfig.release.runtimeInputs;
-                };
   };
 in
 {
-          inherit env;
-          packages = mergeUniqueAttrs "package" releasePackages perSystemResult.packages;
-          apps = perSystemResult.apps;
-        }
-      );
-    in
-    {
-      devShells = lib.genAttrs systems (system: {
-        default = systemResults.${system}.env.shell;
-      });
-
-      checks = lib.genAttrs systems (system: systemResults.${system}.env.checks);
-
-      formatter = lib.genAttrs systems (system: systemResults.${system}.env.formatter);
-      packages = lib.genAttrs systems (system: systemResults.${system}.packages);
-      apps = lib.genAttrs systems (system: systemResults.${system}.apps);
-    };
+  systems.default = defaults.supportedSystems;
+  inherit (toolsModule) tools;
+  inherit (repoModule) normalizeRepoConfig mkRepo;
+  inherit (releaseModule) mkRelease;
 }

packages/repo-lib/lib/common.nix

@@ -0,0 +1,29 @@
+{ nixpkgs }:
+let
+  lib = nixpkgs.lib;
+in
+{
+  inherit lib;
+
+  importPkgs = nixpkgsInput: system: import nixpkgsInput { inherit system; };
+
+  duplicateStrings =
+    names:
+    lib.unique (
+      builtins.filter (
+        name: builtins.length (builtins.filter (candidate: candidate == name) names) > 1
+      ) names
+    );
+
+  mergeUniqueAttrs =
+    label: left: right:
+    let
+      overlap = builtins.attrNames (lib.intersectAttrs left right);
+    in
+    if overlap != [ ] then
+      throw "repo-lib: duplicate ${label}: ${lib.concatStringsSep ", " overlap}"
+    else
+      left // right;
+
+  sanitizeName = name: lib.strings.sanitizeDerivationName name;
+}

packages/repo-lib/lib/defaults.nix

@@ -0,0 +1,26 @@
+{ }:
+{
+  supportedSystems = [
+    "x86_64-linux"
+    "aarch64-linux"
+    "x86_64-darwin"
+    "aarch64-darwin"
+  ];
+
+  defaultReleaseChannels = [
+    "alpha"
+    "beta"
+    "rc"
+    "internal"
+  ];
+
+  defaultShellBanner = {
+    style = "simple";
+    icon = "🚀";
+    title = "Dev shell ready";
+    titleColor = "GREEN";
+    subtitle = "";
+    subtitleColor = "GRAY";
+    borderColor = "BLUE";
+  };
+}

packages/repo-lib/lib/hooks.nix

@@ -0,0 +1,116 @@
+{
+  lib,
+  sanitizeName,
+}:
+let
+  hookStageFileArgs =
+    stage: passFilenames:
+    if !passFilenames then
+      ""
+    else if stage == "pre-commit" then
+      " {staged_files}"
+    else if stage == "pre-push" then
+      " {push_files}"
+    else if stage == "commit-msg" then
+      " {1}"
+    else
+      throw "repo-lib: unsupported lefthook stage '${stage}'";
+
+  normalizeHookStage =
+    hookName: stage:
+    if
+      builtins.elem stage [
+        "pre-commit"
+        "pre-push"
+        "commit-msg"
+      ]
+    then
+      stage
+    else
+      throw "repo-lib: hook '${hookName}' has unsupported stage '${stage}' for lefthook";
+in
+{
+  inherit hookStageFileArgs normalizeHookStage;
+
+  checkToLefthookConfig =
+    pkgs: name: rawCheck:
+    let
+      check = {
+        stage = "pre-commit";
+        passFilenames = false;
+        runtimeInputs = [ ];
+      }
+      // rawCheck;
+      wrapperName = "repo-lib-check-${sanitizeName name}";
+      wrapper = pkgs.writeShellApplication {
+        name = wrapperName;
+        runtimeInputs = check.runtimeInputs;
+        text = ''
+          set -euo pipefail
+          ${check.command}
+        '';
+      };
+    in
+    if !(check ? command) then
+      throw "repo-lib: check '${name}' is missing 'command'"
+    else if
+      !(builtins.elem check.stage [
+        "pre-commit"
+        "pre-push"
+      ])
+    then
+      throw "repo-lib: check '${name}' has unsupported stage '${check.stage}'"
+    else
+      lib.setAttrByPath [ check.stage "commands" name ] {
+        run = "${wrapper}/bin/${wrapperName}${hookStageFileArgs check.stage check.passFilenames}";
+      };
+
+  normalizeLefthookConfig =
+    label: raw: if builtins.isAttrs raw then raw else throw "repo-lib: ${label} must be an attrset";
+
+  hookToLefthookConfig =
+    name: hook:
+    let
+      supportedFields = [
+        "description"
+        "enable"
+        "entry"
+        "name"
+        "package"
+        "pass_filenames"
+        "stages"
+      ];
+      unsupportedFields = builtins.filter (field: !(builtins.elem field supportedFields)) (
+        builtins.attrNames hook
+      );
+      stages = builtins.map (stage: normalizeHookStage name stage) (hook.stages or [ "pre-commit" ]);
+      passFilenames = hook.pass_filenames or false;
+    in
+    if unsupportedFields != [ ] then
+      throw ''
+        repo-lib: hook '${name}' uses unsupported fields for lefthook: ${lib.concatStringsSep ", " unsupportedFields}
+      ''
+    else if !(hook ? entry) then
+      throw "repo-lib: hook '${name}' is missing 'entry'"
+    else
+      lib.foldl' lib.recursiveUpdate { } (
+        builtins.map (
+          stage:
+          lib.setAttrByPath [ stage "commands" name ] {
+            run = "${hook.entry}${hookStageFileArgs stage passFilenames}";
+          }
+        ) stages
+      );
+
+  parallelHookStageConfig =
+    stage:
+    if
+      builtins.elem stage [
+        "pre-commit"
+        "pre-push"
+      ]
+    then
+      lib.setAttrByPath [ stage "parallel" ] true
+    else
+      { };
+}

packages/repo-lib/lib/release.nix

@@ -0,0 +1,105 @@
+{
+  lib,
+  nixpkgs,
+  releaseScriptPath,
+  defaultReleaseChannels,
+  importPkgs,
+}:
+let
+  normalizeReleaseStep =
+    step:
+    if step ? writeFile then
+      {
+        kind = "writeFile";
+        path = step.writeFile.path;
+        text = step.writeFile.text;
+      }
+    else if step ? replace then
+      {
+        kind = "replace";
+        path = step.replace.path;
+        regex = step.replace.regex;
+        replacement = step.replace.replacement;
+      }
+    else if step ? versionMetaSet then
+      {
+        kind = "versionMetaSet";
+        key = step.versionMetaSet.key;
+        value = step.versionMetaSet.value;
+      }
+    else if step ? versionMetaUnset then
+      {
+        kind = "versionMetaUnset";
+        key = step.versionMetaUnset.key;
+      }
+    else
+      throw "repo-lib: release step must contain one of writeFile, replace, versionMetaSet, or versionMetaUnset";
+
+  normalizeReleaseConfig =
+    raw:
+    let
+      steps = if raw ? steps then builtins.map normalizeReleaseStep raw.steps else [ ];
+    in
+    {
+      postVersion = raw.postVersion or "";
+      channels = raw.channels or defaultReleaseChannels;
+      runtimeInputs = raw.runtimeInputs or [ ];
+      steps = steps;
+    };
+
+  mkRelease =
+    {
+      system,
+      nixpkgsInput ? nixpkgs,
+      ...
+    }@rawArgs:
+    let
+      pkgs = importPkgs nixpkgsInput system;
+      release = normalizeReleaseConfig rawArgs;
+      channelList = lib.concatStringsSep " " release.channels;
+      releaseStepsJson = builtins.toJSON release.steps;
+      releaseRunner = pkgs.buildGoModule {
+        pname = "repo-lib-release-runner";
+        version = "0.0.0";
+        src = ../../release;
+        vendorHash = "sha256-fGFteYruAda2MBHkKgbTeCpIgO30tKCa+tzF6HcUvWM=";
+        subPackages = [ "cmd/release" ];
+      };
+      script =
+        builtins.replaceStrings
+          [
+            "__CHANNEL_LIST__"
+            "__RELEASE_STEPS_JSON__"
+            "__POST_VERSION__"
+            "__RELEASE_RUNNER__"
+          ]
+          [
+            channelList
+            releaseStepsJson
+            release.postVersion
+            (lib.getExe' releaseRunner "release")
+          ]
+          (builtins.readFile releaseScriptPath);
+    in
+    pkgs.writeShellApplication {
+      name = "release";
+      runtimeInputs =
+        with pkgs;
+        [
+          git
+          gnugrep
+          gawk
+          gnused
+          coreutils
+        ]
+        ++ release.runtimeInputs;
+      text = script;
+    };
+in
+{
+  inherit
+    normalizeReleaseStep
+    normalizeReleaseConfig
+    mkRelease
+    ;
+}

packages/repo-lib/lib/repo.nix

@@ -0,0 +1,195 @@
+{
+  flake-parts,
+  nixpkgs,
+  lib,
+  importPkgs,
+  duplicateStrings,
+  mergeUniqueAttrs,
+  supportedSystems,
+  defaultReleaseChannels,
+  normalizeStrictTool,
+  normalizeLefthookConfig,
+  normalizeShellBanner,
+  buildShellArtifacts,
+  mkRelease,
+}:
+let
+  normalizeRepoConfig =
+    rawConfig:
+    let
+      merged = lib.recursiveUpdate {
+        includeStandardPackages = true;
+        shell = {
+          env = { };
+          extraShellText = "";
+          allowImpureBootstrap = false;
+          bootstrap = "";
+          banner = { };
+        };
+        formatting = {
+          programs = { };
+          settings = { };
+        };
+        checks = { };
+        lefthook = { };
+        release = null;
+      } rawConfig;
+      release =
+        if merged.release == null then
+          null
+        else
+          {
+            channels = defaultReleaseChannels;
+            steps = [ ];
+            postVersion = "";
+            runtimeInputs = [ ];
+          }
+          // merged.release;
+    in
+    if merged.shell.bootstrap != "" && !merged.shell.allowImpureBootstrap then
+      throw "repo-lib: config.shell.bootstrap requires config.shell.allowImpureBootstrap = true"
+    else
+      merged
+      // {
+        inherit release;
+        shell = merged.shell // {
+          banner = normalizeShellBanner merged.shell.banner;
+        };
+      };
+
+  buildRepoSystemOutputs =
+    {
+      pkgs,
+      system,
+      src,
+      nixpkgsInput,
+      normalizedConfig,
+      userPerSystem,
+    }:
+    let
+      perSystemResult = {
+        tools = [ ];
+        shell = { };
+        checks = { };
+        lefthook = { };
+        packages = { };
+        apps = { };
+      }
+      // userPerSystem {
+        inherit pkgs system;
+        lib = nixpkgs.lib;
+        config = normalizedConfig;
+      };
+
+      strictTools = builtins.map (tool: normalizeStrictTool pkgs tool) perSystemResult.tools;
+      duplicateToolNames = duplicateStrings (builtins.map (tool: tool.name) strictTools);
+      mergedChecks = mergeUniqueAttrs "check" normalizedConfig.checks perSystemResult.checks;
+      mergedLefthookConfig =
+        lib.recursiveUpdate (normalizeLefthookConfig "config.lefthook" normalizedConfig.lefthook)
+          (normalizeLefthookConfig "perSystem.lefthook" (perSystemResult.lefthook or { }));
+      shellConfig = lib.recursiveUpdate normalizedConfig.shell (perSystemResult.shell or { });
+      env =
+        if duplicateToolNames != [ ] then
+          throw "repo-lib: duplicate tool names: ${lib.concatStringsSep ", " duplicateToolNames}"
+        else
+          buildShellArtifacts {
+            inherit
+              pkgs
+              system
+              src
+              ;
+            includeStandardPackages = normalizedConfig.includeStandardPackages;
+            formatting = normalizedConfig.formatting;
+            tools = strictTools;
+            checkSpecs = mergedChecks;
+            lefthookConfig = mergedLefthookConfig;
+            shellConfig = shellConfig;
+            extraPackages = perSystemResult.shell.packages or [ ];
+          };
+
+      releasePackages =
+        if normalizedConfig.release == null then
+          { }
+        else
+          {
+            release = mkRelease {
+              inherit system;
+              nixpkgsInput = nixpkgsInput;
+              channels = normalizedConfig.release.channels;
+              steps = normalizedConfig.release.steps;
+              postVersion = normalizedConfig.release.postVersion;
+              runtimeInputs = normalizedConfig.release.runtimeInputs;
+            };
+          };
+    in
+    {
+      checks = env.checks;
+      formatter = env.formatter;
+      shell = env.shell;
+      packages = mergeUniqueAttrs "package" releasePackages perSystemResult.packages;
+      apps = perSystemResult.apps;
+    };
+in
+{
+  inherit normalizeRepoConfig;
+
+  mkRepo =
+    {
+      self,
+      nixpkgs,
+      src ? ./.,
+      systems ? supportedSystems,
+      config ? { },
+      perSystem ? (
+        {
+          pkgs,
+          system,
+          lib,
+          config,
+        }:
+        { }
+      ),
+    }:
+    let
+      normalizedConfig = normalizeRepoConfig config;
+      userPerSystem = perSystem;
+    in
+    flake-parts.lib.mkFlake
+      {
+        inputs = {
+          inherit self nixpkgs;
+          flake-parts = flake-parts;
+        };
+      }
+      {
+        inherit systems;
+
+        perSystem =
+          {
+            pkgs,
+            system,
+            ...
+          }:
+          let
+            systemOutputs = buildRepoSystemOutputs {
+              inherit
+                pkgs
+                system
+                src
+                normalizedConfig
+                ;
+              nixpkgsInput = nixpkgs;
+              userPerSystem = userPerSystem;
+            };
+          in
+          {
+            devShells.default = systemOutputs.shell;
+            inherit (systemOutputs)
+              apps
+              checks
+              formatter
+              packages
+              ;
+          };
+      };
+}

packages/repo-lib/lib/shell.nix

@@ -0,0 +1,221 @@
+{
+  lib,
+  treefmt-nix,
+  lefthookNix,
+  shellHookTemplatePath,
+  defaultShellBanner,
+  normalizeShellBanner,
+  normalizeLefthookConfig,
+  parallelHookStageConfig,
+  checkToLefthookConfig,
+  hookToLefthookConfig,
+}:
+let
+  buildShellHook =
+    {
+      hooksShellHook,
+      shellEnvScript,
+      bootstrap,
+      shellBannerScript,
+      extraShellText,
+      toolLabelWidth,
+    }:
+    let
+      template = builtins.readFile shellHookTemplatePath;
+    in
+    builtins.replaceStrings
+      [
+        "@HOOKS_SHELL_HOOK@"
+        "@TOOL_LABEL_WIDTH@"
+        "@SHELL_ENV_SCRIPT@"
+        "@BOOTSTRAP@"
+        "@SHELL_BANNER_SCRIPT@"
+        "@EXTRA_SHELL_TEXT@"
+      ]
+      [
+        hooksShellHook
+        (toString toolLabelWidth)
+        shellEnvScript
+        bootstrap
+        shellBannerScript
+        extraShellText
+      ]
+      template;
+in
+{
+  inherit buildShellHook;
+
+  buildShellArtifacts =
+    {
+      pkgs,
+      system,
+      src,
+      includeStandardPackages ? true,
+      formatting,
+      tools ? [ ],
+      shellConfig ? {
+        env = { };
+        extraShellText = "";
+        bootstrap = "";
+        banner = defaultShellBanner;
+      },
+      checkSpecs ? { },
+      rawHookEntries ? { },
+      lefthookConfig ? { },
+      extraPackages ? [ ],
+    }:
+    let
+      standardPackages = with pkgs; [
+        nixfmt
+        gitlint
+        gitleaks
+        shfmt
+      ];
+      toolPackages = lib.filter (pkg: pkg != null) (builtins.map (tool: tool.package or null) tools);
+      selectedStandardPackages = lib.optionals includeStandardPackages standardPackages;
+
+      treefmtEval = treefmt-nix.lib.evalModule pkgs {
+        projectRootFile = "flake.nix";
+        programs = {
+          nixfmt.enable = true;
+        }
+        // formatting.programs;
+        settings.formatter = { } // formatting.settings;
+      };
+      treefmtWrapper = treefmtEval.config.build.wrapper;
+      lefthookBinWrapper = pkgs.writeShellScript "lefthook-dumb-term" ''
+        exec env TERM=dumb ${lib.getExe pkgs.lefthook} "$@"
+      '';
+
+      normalizedLefthookConfig = normalizeLefthookConfig "lefthook config" lefthookConfig;
+      lefthookCheck = lefthookNix.lib.${system}.run {
+        inherit src;
+        config = lib.foldl' lib.recursiveUpdate { } (
+          [
+            {
+              output = [
+                "failure"
+                "summary"
+              ];
+            }
+            (parallelHookStageConfig "pre-commit")
+            (parallelHookStageConfig "pre-push")
+            (lib.setAttrByPath [ "pre-commit" "commands" "treefmt" ] {
+              run = "${treefmtWrapper}/bin/treefmt --no-cache {staged_files}";
+              stage_fixed = true;
+            })
+            (lib.setAttrByPath [ "pre-commit" "commands" "gitleaks" ] {
+              run = "${pkgs.gitleaks}/bin/gitleaks protect --staged";
+            })
+            (lib.setAttrByPath [ "commit-msg" "commands" "gitlint" ] {
+              run = "${pkgs.gitlint}/bin/gitlint --staged --msg-filename {1}";
+            })
+          ]
+          ++ lib.mapAttrsToList (name: check: checkToLefthookConfig pkgs name check) checkSpecs
+          ++ lib.mapAttrsToList hookToLefthookConfig rawHookEntries
+          ++ [ normalizedLefthookConfig ]
+        );
+      };
+      selectedCheckOutputs = {
+        formatting-check = treefmtEval.config.build.check src;
+        hook-check = lefthookCheck;
+        lefthook-check = lefthookCheck;
+      };
+
+      toolNames = builtins.map (tool: tool.name) tools;
+      toolNameWidth =
+        if toolNames == [ ] then
+          0
+        else
+          builtins.foldl' (maxWidth: name: lib.max maxWidth (builtins.stringLength name)) 0 toolNames;
+      toolLabelWidth = toolNameWidth + 1;
+
+      shellEnvScript = lib.concatStringsSep "\n" (
+        lib.mapAttrsToList (
+          name: value: "export ${name}=${lib.escapeShellArg (toString value)}"
+        ) shellConfig.env
+      );
+
+      banner = normalizeShellBanner (shellConfig.banner or { });
+
+      shellBannerScript =
+        if banner.style == "pretty" then
+          ''
+            repo_lib_print_pretty_header \
+              ${lib.escapeShellArg banner.borderColor} \
+              ${lib.escapeShellArg banner.titleColor} \
+              ${lib.escapeShellArg banner.icon} \
+              ${lib.escapeShellArg banner.title} \
+              ${lib.escapeShellArg banner.subtitleColor} \
+              ${lib.escapeShellArg banner.subtitle}
+          ''
+          + lib.concatMapStrings (tool: ''
+            repo_lib_print_pretty_tool \
+              ${lib.escapeShellArg banner.borderColor} \
+              ${lib.escapeShellArg tool.name} \
+              ${lib.escapeShellArg tool.banner.color} \
+              ${lib.escapeShellArg (if tool.banner.icon == null then "" else tool.banner.icon)} \
+              ${lib.escapeShellArg (if tool.banner.iconColor == null then "" else tool.banner.iconColor)} \
+              ${lib.escapeShellArg (if tool.required then "1" else "0")} \
+              ${lib.escapeShellArg (toString tool.version.line)} \
+              ${lib.escapeShellArg (toString tool.version.group)} \
+              ${lib.escapeShellArg (if tool.version.regex == null then "" else tool.version.regex)} \
+              ${lib.escapeShellArg (if tool.version.match == null then "" else tool.version.match)} \
+              ${lib.escapeShellArg tool.executable} \
+              ${lib.escapeShellArgs tool.version.args}
+          '') tools
+          + ''
+            repo_lib_print_pretty_footer \
+              ${lib.escapeShellArg banner.borderColor}
+          ''
+        else
+          ''
+            repo_lib_print_simple_header \
+              ${lib.escapeShellArg banner.titleColor} \
+              ${lib.escapeShellArg banner.icon} \
+              ${lib.escapeShellArg banner.title} \
+              ${lib.escapeShellArg banner.subtitleColor} \
+              ${lib.escapeShellArg banner.subtitle}
+          ''
+          + lib.concatMapStrings (tool: ''
+            repo_lib_print_simple_tool \
+              ${lib.escapeShellArg tool.name} \
+              ${lib.escapeShellArg tool.banner.color} \
+              ${lib.escapeShellArg (if tool.banner.icon == null then "" else tool.banner.icon)} \
+              ${lib.escapeShellArg (if tool.banner.iconColor == null then "" else tool.banner.iconColor)} \
+              ${lib.escapeShellArg (if tool.required then "1" else "0")} \
+              ${lib.escapeShellArg (toString tool.version.line)} \
+              ${lib.escapeShellArg (toString tool.version.group)} \
+              ${lib.escapeShellArg (if tool.version.regex == null then "" else tool.version.regex)} \
+              ${lib.escapeShellArg (if tool.version.match == null then "" else tool.version.match)} \
+              ${lib.escapeShellArg tool.executable} \
+              ${lib.escapeShellArgs tool.version.args}
+          '') tools
+          + ''
+            printf "\n"
+          '';
+    in
+    {
+      checks = selectedCheckOutputs;
+      formatter = treefmtWrapper;
+      shell = pkgs.mkShell {
+        LEFTHOOK_BIN = builtins.toString lefthookBinWrapper;
+        packages = lib.unique (
+          selectedStandardPackages
+          ++ extraPackages
+          ++ toolPackages
+          ++ [
+            pkgs.lefthook
+            treefmtWrapper
+          ]
+        );
+        shellHook = buildShellHook {
+          hooksShellHook = lefthookCheck.shellHook;
+          inherit toolLabelWidth shellEnvScript shellBannerScript;
+          bootstrap = shellConfig.bootstrap;
+          extraShellText = shellConfig.extraShellText;
+        };
+      };
+    }
+    // selectedCheckOutputs;
+}

packages/repo-lib/lib/tools.nix

@@ -0,0 +1,90 @@
+{
+  lib,
+}:
+let
+  normalizeStrictTool =
+    pkgs: tool:
+    let
+      version = {
+        args = [ "--version" ];
+        match = null;
+        regex = null;
+        group = 0;
+        line = 1;
+      }
+      // (tool.version or { });
+      banner = {
+        color = "YELLOW";
+        icon = null;
+        iconColor = null;
+      }
+      // (tool.banner or { });
+      executable =
+        if tool ? command && tool.command != null then
+          tool.command
+        else if tool ? exe && tool.exe != null then
+          "${lib.getExe' tool.package tool.exe}"
+        else
+          "${lib.getExe tool.package}";
+    in
+    if !(tool ? command && tool.command != null) && !(tool ? package) then
+      throw "repo-lib: tool '${tool.name or "<unnamed>"}' is missing 'package' or 'command'"
+    else
+      {
+        kind = "strict";
+        inherit executable version banner;
+        name = tool.name;
+        package = tool.package or null;
+        required = tool.required or true;
+      };
+in
+{
+  inherit normalizeStrictTool;
+
+  tools = rec {
+    fromPackage =
+      {
+        name,
+        package,
+        exe ? null,
+        version ? { },
+        banner ? { },
+        required ? true,
+      }:
+      {
+        inherit
+          name
+          package
+          exe
+          version
+          banner
+          required
+          ;
+      };
+
+    fromCommand =
+      {
+        name,
+        command,
+        version ? { },
+        banner ? { },
+        required ? true,
+      }:
+      {
+        inherit
+          name
+          command
+          version
+          banner
+          required
+          ;
+      };
+
+    simple =
+      name: package: args:
+      fromPackage {
+        inherit name package;
+        version.args = args;
+      };
+  };
+}

packages/repo-lib/shell-hook.sh

@@ -70,39 +70,6 @@ repo_lib_capture_tool() {
   return 0
 }
 
-repo_lib_capture_legacy_tool() {
-  local required="$1"
-  local command_name="$2"
-  local version_command="$3"
-
-  local output=""
-  local version=""
-
-  REPO_LIB_TOOL_VERSION=""
-  REPO_LIB_TOOL_ERROR=""
-
-  if ! command -v "$command_name" >/dev/null 2>&1; then
-    REPO_LIB_TOOL_ERROR="missing command"
-    return 1
-  fi
-
-  if ! output="$(sh -c "$command_name $version_command" 2>&1)"; then
-    REPO_LIB_TOOL_ERROR="probe failed"
-    printf "%s\n" "$output" >&2
-    return 1
-  fi
-
-  version="$(printf '%s\n' "$output" | head -n 1 | sed -E 's/^[[:space:]]+//; s/[[:space:]]+$//')"
-  if [ -z "$version" ]; then
-    REPO_LIB_TOOL_ERROR="empty version"
-    printf "%s\n" "$output" >&2
-    return 1
-  fi
-
-  REPO_LIB_TOOL_VERSION="$version"
-  return 0
-}
-
 repo_lib_print_simple_header() {
   local title_color_name="$1"
   local icon="$2"
@@ -164,42 +131,6 @@ repo_lib_print_simple_tool() {
   fi
 }
 
-repo_lib_print_simple_legacy_tool() {
-  local name="$1"
-  local color_name="$2"
-  local icon="$3"
-  local icon_color_name="$4"
-  local required="$5"
-  local command_name="$6"
-  local version_command="$7"
-
-  local color="${!color_name:-$YELLOW}"
-  local effective_icon_color_name="$icon_color_name"
-  local icon_color=""
-
-  if [ -z "$effective_icon_color_name" ]; then
-    effective_icon_color_name="$color_name"
-  fi
-
-  if repo_lib_capture_legacy_tool "$required" "$command_name" "$version_command"; then
-    icon_color="${!effective_icon_color_name:-$color}"
-    printf "  "
-    if [ -n "$icon" ]; then
-      printf "%s%s%s " "$icon_color" "$icon" "$RESET"
-    fi
-    printf "$CYAN %-@TOOL_LABEL_WIDTH@s$RESET %s%s$RESET\n" "${name}:" "$color" "$REPO_LIB_TOOL_VERSION"
-  else
-    printf "  "
-    if [ -n "$icon" ]; then
-      printf "%s%s%s " "$RED" "$icon" "$RESET"
-    fi
-    printf "$CYAN %-@TOOL_LABEL_WIDTH@s$RESET $RED%s$RESET\n" "${name}:" "$REPO_LIB_TOOL_ERROR"
-    if [ "$required" = "1" ]; then
-      exit 1
-    fi
-  fi
-}
-
 repo_lib_print_pretty_header() {
   local border_color_name="$1"
   local title_color_name="$2"
@@ -286,45 +217,6 @@ repo_lib_print_pretty_tool() {
   fi
 }
 
-repo_lib_print_pretty_legacy_tool() {
-  local border_color_name="$1"
-  local name="$2"
-  local color_name="$3"
-  local icon="$4"
-  local icon_color_name="$5"
-  local required="$6"
-  local command_name="$7"
-  local version_command="$8"
-
-  local effective_icon_color_name="$icon_color_name"
-  local value_color_name="$color_name"
-  local value=""
-
-  if [ -z "$effective_icon_color_name" ]; then
-    effective_icon_color_name="$color_name"
-  fi
-
-  if repo_lib_capture_legacy_tool "$required" "$command_name" "$version_command"; then
-    value="$REPO_LIB_TOOL_VERSION"
-  else
-    value="$REPO_LIB_TOOL_ERROR"
-    effective_icon_color_name="RED"
-    value_color_name="RED"
-  fi
-
-  repo_lib_print_pretty_row \
-    "$border_color_name" \
-    "$icon" \
-    "$effective_icon_color_name" \
-    "$name" \
-    "$value" \
-    "$value_color_name"
-
-  if [ "$value_color_name" = "RED" ] && [ "$required" = "1" ]; then
-    exit 1
-  fi
-}
-
 repo_lib_print_pretty_footer() {
   local border_color_name="$1"
   local border_color="${!border_color_name:-$BLUE}"

template/flake.nix

@@ -3,7 +3,7 @@
 
   inputs = {
     nixpkgs.url = "github:nixos/nixpkgs?ref=nixos-unstable";
-    repo-lib.url = "git+https://git.dgren.dev/eric/nix-flake-lib?ref=refs/tags/v3.5.0";
+    repo-lib.url = "git+https://git.dgren.dev/eric/nix-flake-lib?ref=refs/tags/v3.5.1";
     repo-lib.inputs.nixpkgs.follows = "nixpkgs";
   };