diff --git a/bun.lockb b/bun.lockb
index af0fdb4..e6ce3f8 100755
Binary files a/bun.lockb and b/bun.lockb differ
diff --git a/package.json b/package.json
index 3c3375f..cc77a8c 100644
--- a/package.json
+++ b/package.json
@@ -19,6 +19,7 @@
   },
   "dependencies": {
     "@ai-sdk/openai": "^0.0.13",
+    "@noble/ciphers": "^1.3.0",
     "@discordjs/opus": "^0.10.0",
     "@discordjs/voice": "^0.18.0",
     "@elysiajs/cors": "^1.4.0",
diff --git a/src/features/joel/index.ts b/src/features/joel/index.ts
index eb75960..ce2488b 100644
--- a/src/features/joel/index.ts
+++ b/src/features/joel/index.ts
@@ -7,3 +7,4 @@ export { getRandomMention, getRandomMemberMention } from "./mentions";
 export { startSpontaneousMentionsCron, stopSpontaneousMentionsCron } from "./spontaneous-cron";
 export { TypingIndicator } from "./typing";
 export { personalities, getPersonality, buildStyledPrompt, STYLE_MODIFIERS } from "./personalities";
+export { logVoiceDependencyHealth, speakVoiceover } from "./voice";
diff --git a/src/features/joel/voice.ts b/src/features/joel/voice.ts
index fb1ed44..7e467cc 100644
--- a/src/features/joel/voice.ts
+++ b/src/features/joel/voice.ts
@@ -8,6 +8,7 @@ import {
     createAudioPlayer,
     createAudioResource,
     entersState,
+    generateDependencyReport,
     getVoiceConnection,
     joinVoiceChannel,
     StreamType,
@@ -25,11 +26,89 @@ const logger = createLogger("Features:Joel:Voice");
 const MAX_VOICE_TEXT_LENGTH = 800;
 const PLAYBACK_TIMEOUT_MS = 60_000;
 const READY_TIMEOUT_MS = 15_000;
+const VOICE_DEPENDENCY_REPORT = generateDependencyReport();
+
+type VoiceDependencyHealth = {
+    hasEncryptionLibrary: boolean;
+    hasFfmpeg: boolean;
+    hasOpusLibrary: boolean;
+    report: string;
+};
+
+type VoiceConnectionResult = {
+    channelId: string | null;
+    connection: VoiceConnection | null;
+    skipReason?: string;
+};
+
+type VoicePlaybackEvent = {
+    authorId: string;
+    audioBytes?: number;
+    channelId: string | null;
+    connectionStatus?: string;
+    durationMs?: number;
+    errorMessage?: string;
+    guildId: string;
+    outcome: "skipped" | "success" | "error";
+    playerStarted: boolean;
+    skipReason?: string;
+    textLength: number;
+};
+
+function extractDependencySection(startHeading: string, endHeading?: string): string {
+    const startToken = `${startHeading}\n`;
+    const startIndex = VOICE_DEPENDENCY_REPORT.indexOf(startToken);
+    if (startIndex === -1) {
+        return "";
+    }
+
+    const sectionStart = startIndex + startToken.length;
+    const endIndex = endHeading
+        ? VOICE_DEPENDENCY_REPORT.indexOf(`\n${endHeading}`, sectionStart)
+        : -1;
+
+    return VOICE_DEPENDENCY_REPORT
+        .slice(sectionStart, endIndex === -1 ? undefined : endIndex)
+        .trim();
+}
+
+function hasInstalledDependency(section: string): boolean {
+    return section
+        .split("\n")
+        .some((line) => line.trim().startsWith("-") && !line.includes("not found"));
+}
+
+function getVoiceDependencyHealth(): VoiceDependencyHealth {
+    const opusSection = extractDependencySection("Opus Libraries", "Encryption Libraries");
+    const encryptionSection = extractDependencySection("Encryption Libraries", "FFmpeg");
+
+    const hasOpusLibrary = hasInstalledDependency(opusSection);
+    const hasEncryptionLibrary = hasInstalledDependency(encryptionSection);
+    const hasFfmpeg = /FFmpeg[\s\S]*- version:\s+(?!not found)/.test(VOICE_DEPENDENCY_REPORT)
+        && VOICE_DEPENDENCY_REPORT.includes("- libopus: yes");
+
+    return {
+        hasEncryptionLibrary,
+        hasFfmpeg,
+        hasOpusLibrary,
+        report: VOICE_DEPENDENCY_REPORT,
+    };
+}
+
+const voiceDependencyHealth = getVoiceDependencyHealth();
 
 function isAbortError(error: unknown): boolean {
     return error instanceof Error && error.name === "AbortError";
 }
 
+function getErrorMessage(error: unknown): string {
+    if (error instanceof Error) {
+        return error.message;
+    }
+
+    return typeof error === "string" ? error : "Unknown error";
+}
+
 function resolveMentions(message: Message<true>, content: string): string {
     let text = content;
 
@@ -88,14 +167,18 @@ function attachConnectionLogging(connection: VoiceConnection, guildId: string, c
     });
 }
 
-async function getOrCreateConnection(message: Message<true>) {
+async function getOrCreateConnection(message: Message<true>): Promise<VoiceConnectionResult> {
     const voiceChannel = message.member?.voice.channel;
     if (!voiceChannel) {
         logger.debug("No voice channel for author", {
             userId: message.author.id,
             guildId: message.guildId,
         });
-        return null;
+        return {
+            channelId: null,
+            connection: null,
+            skipReason: "author_not_in_voice_channel",
+        };
     }
 
     const me = message.guild.members.me ?? (await message.guild.members.fetchMe());
@@ -105,7 +188,11 @@ async function getOrCreateConnection(message: Message<true>) {
             guildId: message.guildId,
             channelId: voiceChannel.id,
         });
-        return null;
+        return {
+            channelId: voiceChannel.id,
+            connection: null,
+            skipReason: "missing_connect_or_speak_permission",
+        };
     }
 
     const existing = getVoiceConnection(message.guildId);
@@ -114,7 +201,10 @@ async function getOrCreateConnection(message: Message<true>) {
             guildId: message.guildId,
             channelId: voiceChannel.id,
         });
-        return existing;
+        return {
+            channelId: voiceChannel.id,
+            connection: existing,
+        };
     }
 
     if (existing) {
@@ -140,7 +230,10 @@ async function getOrCreateConnection(message: Message<true>) {
             guildId: message.guildId,
             channelId: voiceChannel.id,
         });
-        return connection;
+        return {
+            channelId: voiceChannel.id,
+            connection,
+        };
     } catch (error) {
         if (isAbortError(error)) {
             logger.debug("Voice connection ready timeout", {
@@ -152,41 +245,103 @@ async function getOrCreateConnection(message: Message<true>) {
             logger.error("Voice connection failed to become ready", error);
         }
         connection.destroy();
-        return null;
+        return {
+            channelId: voiceChannel.id,
+            connection: null,
+            skipReason: isAbortError(error) ? "voice_connection_ready_timeout" : "voice_connection_failed",
+        };
     }
 }
 
+export function logVoiceDependencyHealth(): void {
+    const payload = {
+        hasEncryptionLibrary: voiceDependencyHealth.hasEncryptionLibrary,
+        hasFfmpeg: voiceDependencyHealth.hasFfmpeg,
+        hasOpusLibrary: voiceDependencyHealth.hasOpusLibrary,
+    };
+
+    if (voiceDependencyHealth.hasEncryptionLibrary && voiceDependencyHealth.hasFfmpeg && voiceDependencyHealth.hasOpusLibrary) {
+        logger.info("Discord voice dependency health", payload);
+        return;
+    }
+
+    logger.warn("Discord voice dependency health degraded", {
+        ...payload,
+        report: voiceDependencyHealth.report,
+    });
+}
+
 export async function speakVoiceover(message: Message<true>, content: string): Promise<void> {
+    const playbackEvent: VoicePlaybackEvent = {
+        authorId: message.author.id,
+        channelId: null,
+        guildId: message.guildId,
+        outcome: "skipped",
+        playerStarted: false,
+        textLength: 0,
+    };
+    const startedAt = Date.now();
+
     if (!config.elevenlabs.apiKey || !config.elevenlabs.voiceId) {
         logger.debug("Voiceover disabled (missing config)");
+        playbackEvent.skipReason = "missing_elevenlabs_config";
+        playbackEvent.durationMs = Date.now() - startedAt;
+        logger.info("Voice playback", playbackEvent);
+        return;
+    }
+
+    if (!voiceDependencyHealth.hasEncryptionLibrary) {
+        playbackEvent.skipReason = "missing_voice_encryption_dependency";
+        playbackEvent.durationMs = Date.now() - startedAt;
+        logger.warn("Voice playback skipped", {
+            ...playbackEvent,
+            dependencyReport: voiceDependencyHealth.report,
+        });
         return;
     }
 
     const text = sanitizeForVoiceover(message, content);
+    playbackEvent.textLength = text.length;
     if (!text) {
         logger.debug("Voiceover skipped (empty text after sanitize)");
+        playbackEvent.skipReason = "empty_text_after_sanitize";
+        playbackEvent.durationMs = Date.now() - startedAt;
+        logger.info("Voice playback", playbackEvent);
         return;
     }
 
     let connection: VoiceConnection | null = null;
 
     try {
-        connection = await getOrCreateConnection(message);
+        const connectionResult = await getOrCreateConnection(message);
+        playbackEvent.channelId = connectionResult.channelId;
+        connection = connectionResult.connection;
+
         if (!connection) {
             logger.debug("Voiceover skipped (no connection)", {
                 guildId: message.guildId,
                 authorId: message.author.id,
+                skipReason: connectionResult.skipReason,
             });
+            playbackEvent.skipReason = connectionResult.skipReason ?? "no_connection";
             return;
         }
 
+        logger.info("Voice playback started", {
+            authorId: message.author.id,
+            channelId: playbackEvent.channelId,
+            guildId: message.guildId,
+            textLength: playbackEvent.textLength,
+        });
+
         const voiceover = getVoiceoverService();
         logger.debug("Requesting ElevenLabs voiceover", { textLength: text.length });
         const audio = await voiceover.generate({ text });
         logger.debug("Voiceover audio received", { bytes: audio.length });
+        playbackEvent.audioBytes = audio.length;
 
         const player = createAudioPlayer();
-        const resource = createAudioResource(Readable.from(audio), {
+        const resource = createAudioResource(Readable.from([audio]), {
             inputType: StreamType.Arbitrary,
         });
 
@@ -196,6 +351,7 @@ export async function speakVoiceover(message: Message<true>, content: string): P
 
         player.on(AudioPlayerStatus.Playing, () => {
             logger.debug("Audio player started", { guildId: message.guildId });
+            playbackEvent.playerStarted = true;
         });
 
         player.on(AudioPlayerStatus.Idle, () => {
@@ -205,13 +361,33 @@ export async function speakVoiceover(message: Message<true>, content: string): P
         connection.subscribe(player);
         player.play(resource);
 
-        await entersState(player, AudioPlayerStatus.Playing, 5_000).catch(() => undefined);
+        const playingState = await entersState(player, AudioPlayerStatus.Playing, 5_000).catch(() => undefined);
+        if (!playingState) {
+            logger.warn("Voice playback did not enter playing state", {
+                authorId: message.author.id,
+                channelId: playbackEvent.channelId,
+                guildId: message.guildId,
+                playerStarted: playbackEvent.playerStarted,
+            });
+        }
         await entersState(player, AudioPlayerStatus.Idle, PLAYBACK_TIMEOUT_MS);
+        playbackEvent.connectionStatus = connection.state.status;
+        playbackEvent.outcome = "success";
     } catch (error) {
+        playbackEvent.connectionStatus = connection?.state.status;
+        playbackEvent.errorMessage = getErrorMessage(error);
+        playbackEvent.outcome = "error";
         if (!isAbortError(error)) {
             logger.error("Voiceover playback failed", error);
         }
     } finally {
+        playbackEvent.durationMs = Date.now() - startedAt;
+        if (playbackEvent.outcome === "error") {
+            logger.warn("Voice playback", playbackEvent);
+        } else {
+            logger.info("Voice playback", playbackEvent);
+        }
+
         if (connection && connection.state.status !== VoiceConnectionStatus.Destroyed) {
             connection.destroy();
         }
diff --git a/src/index.ts b/src/index.ts
index 8d01364..a41adf8 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -16,7 +16,7 @@ import { BotClient } from "./core/client";
 import { config } from "./core/config";
 import { createLogger } from "./core/logger";
 import { registerEvents } from "./events";
-import { stopSpontaneousMentionsCron } from "./features/joel";
+import { logVoiceDependencyHealth, stopSpontaneousMentionsCron } from "./features/joel";
 import { buildWebCss, startWebCssWatcher, startWebServer } from "./web";
 import { runMigrations } from "./database/migrate";
 import type { FSWatcher } from "fs";
@@ -47,6 +47,7 @@ async function main(): Promise<void> {
   try {
     // Run database migrations
     await runMigrations();
+    logVoiceDependencyHealth();
 
     await client.login(config.discord.token);
 
diff --git a/src/web/index.ts b/src/web/index.ts
index 2c163d8..27ee936 100644
--- a/src/web/index.ts
+++ b/src/web/index.ts
@@ -31,6 +31,23 @@ const logger = createLogger("Web");
 const pendingStates = new Map<string, { createdAt: number }>();
 const STATE_EXPIRY_MS = 5 * 60 * 1000;
 
+function getErrorMessage(error: unknown): string {
+  if (error instanceof Error) {
+    return error.message;
+  }
+
+  return typeof error === "string" ? error : "Unknown error";
+}
+
+function escapeHtml(value: string): string {
+  return value
+    .replaceAll("&", "&amp;")
+    .replaceAll("<", "&lt;")
+    .replaceAll(">", "&gt;")
+    .replaceAll("\"", "&quot;")
+    .replaceAll("'", "&#39;");
+}
+
 export function createWebServer(client: BotClient) {
   return new Elysia()
     .use(html())
@@ -113,8 +130,16 @@ export function createWebServer(client: BotClient) {
 
         return new Response(null, { status: 302, headers });
       } catch (err) {
-        logger.error("OAuth callback failed", err);
-        return htmlResponse("<h1>Authentication failed</h1>", 500);
+        const errorMessage = getErrorMessage(err);
+        logger.error("OAuth callback failed", {
+          codePresent: !!code,
+          errorMessage,
+          state,
+        });
+        return htmlResponse(
+          `<h1>Authentication failed</h1><p>${escapeHtml(errorMessage)}</p>`,
+          500
+        );
       }
     })
     .post("/auth/logout", async ({ request }) => {
diff --git a/src/web/oauth.ts b/src/web/oauth.ts
index 6922b83..ddaab6a 100644
--- a/src/web/oauth.ts
+++ b/src/web/oauth.ts
@@ -19,6 +19,12 @@ const userGuildsCache = new Map<string, CacheEntry<DiscordGuild[]>>();
 const inFlightUserRequests = new Map<string, Promise<DiscordUser>>();
 const inFlightGuildRequests = new Map<string, Promise<DiscordGuild[]>>();
 
+async function throwDiscordApiError(action: string, response: Response): Promise<never> {
+  const bodyText = (await response.text()).slice(0, 500);
+  const detail = bodyText ? ` ${bodyText}` : "";
+  throw new Error(`${action} failed (${response.status} ${response.statusText}).${detail}`);
+}
+
 function getFromCache<T>(cache: Map<string, CacheEntry<T>>, key: string): T | null {
   const entry = cache.get(key);
   if (!entry) {
@@ -91,7 +97,7 @@ export async function exchangeCode(code: string): Promise<TokenResponse> {
   });
 
   if (!response.ok) {
-    throw new Error(`Failed to exchange code: ${response.statusText}`);
+    await throwDiscordApiError("OAuth code exchange", response);
   }
 
   return response.json();
@@ -112,7 +118,7 @@ export async function refreshToken(refreshToken: string): Promise<TokenResponse>
   });
 
   if (!response.ok) {
-    throw new Error(`Failed to refresh token: ${response.statusText}`);
+    await throwDiscordApiError("OAuth token refresh", response);
   }
 
   return response.json();
@@ -137,7 +143,7 @@ export async function getUser(accessToken: string): Promise<DiscordUser> {
   });
 
   if (!response.ok) {
-    throw new Error(`Failed to get user: ${response.statusText}`);
+    await throwDiscordApiError("Discord get user", response);
   }
 
     const user = await response.json();
@@ -173,7 +179,7 @@ export async function getUserGuilds(accessToken: string): Promise<DiscordGuild[]
   });
 
   if (!response.ok) {
-    throw new Error(`Failed to get user guilds: ${response.statusText}`);
+    await throwDiscordApiError("Discord get user guilds", response);
   }
 
     const guilds = await response.json();