telegram: exit when Claude Code closes the connection

When the MCP stdio transport closes, the bot kept polling Telegram as
a zombie process — holding the token and causing 409 Conflict for the
next session.

- Listen for stdin end/close and SIGTERM/SIGINT -> bot.stop() + exit
- Force-exit after 2s if bot.stop() stalls on the long-poll timeout
- unref the approval-check interval so it doesn't keep us alive

Fixes #793, partial #788 (issue 3)

external_plugins/discord/server.ts

@@ -25,7 +25,7 @@ import {
   type Attachment,
 } from 'discord.js'
 import { randomBytes } from 'crypto'
-import { readFileSync, writeFileSync, mkdirSync, readdirSync, rmSync, statSync, renameSync, realpathSync } from 'fs'
+import { readFileSync, writeFileSync, mkdirSync, readdirSync, rmSync, statSync, renameSync, realpathSync, chmodSync } from 'fs'
 import { homedir } from 'os'
 import { join, sep } from 'path'
 
@@ -37,6 +37,8 @@ const ENV_FILE = join(STATE_DIR, '.env')
 // Load ~/.claude/channels/discord/.env into process.env. Real env wins.
 // Plugin-spawned servers don't get an env block — this is where the token lives.
 try {
+  // Token is a credential — lock to owner. No-op on Windows (would need ACLs).
+  chmodSync(ENV_FILE, 0o600)
   for (const line of readFileSync(ENV_FILE, 'utf8').split('\n')) {
     const m = line.match(/^(\w+)=(.*)$/)
     if (m && process.env[m[1]] === undefined) process.env[m[1]] = m[2]

external_plugins/discord/skills/configure/SKILL.md

@@ -80,7 +80,8 @@ as the correct long-term choice. Don't skip the lockdown offer.
 2. `mkdir -p ~/.claude/channels/discord`
 3. Read existing `.env` if present; update/add the `DISCORD_BOT_TOKEN=` line,
    preserve other keys. Write back, no quotes around the value.
-4. Confirm, then show the no-args status so the user sees where they stand.
+4. `chmod 600 ~/.claude/channels/discord/.env` — the token is a credential.
+5. Confirm, then show the no-args status so the user sees where they stand.
 
 ### `clear` — remove the token
 

external_plugins/telegram/server.ts

@@ -18,7 +18,7 @@ import {
 import { Bot, InputFile, type Context } from 'grammy'
 import type { ReactionTypeEmoji } from 'grammy/types'
 import { randomBytes } from 'crypto'
-import { readFileSync, writeFileSync, mkdirSync, readdirSync, rmSync, statSync, renameSync, realpathSync } from 'fs'
+import { readFileSync, writeFileSync, mkdirSync, readdirSync, rmSync, statSync, renameSync, realpathSync, chmodSync } from 'fs'
 import { homedir } from 'os'
 import { join, extname, sep } from 'path'
 
@@ -30,6 +30,8 @@ const ENV_FILE = join(STATE_DIR, '.env')
 // Load ~/.claude/channels/telegram/.env into process.env. Real env wins.
 // Plugin-spawned servers don't get an env block — this is where the token lives.
 try {
+  // Token is a credential — lock to owner. No-op on Windows (would need ACLs).
+  chmodSync(ENV_FILE, 0o600)
   for (const line of readFileSync(ENV_FILE, 'utf8').split('\n')) {
     const m = line.match(/^(\w+)=(.*)$/)
     if (m && process.env[m[1]] === undefined) process.env[m[1]] = m[2]
@@ -302,7 +304,7 @@ function checkApprovals(): void {
   }
 }
 
-if (!STATIC) setInterval(checkApprovals, 5000)
+if (!STATIC) setInterval(checkApprovals, 5000).unref()
 
 // Telegram caps messages at 4096 chars. Split long replies, preferring
 // paragraph boundaries when chunkMode is 'newline'.
@@ -505,6 +507,24 @@ mcp.setRequestHandler(CallToolRequestSchema, async req => {
 
 await mcp.connect(new StdioServerTransport())
 
+// When Claude Code closes the MCP connection, stdin gets EOF. Without this
+// the bot keeps polling forever as a zombie, holding the token and blocking
+// the next session with 409 Conflict.
+let shuttingDown = false
+function shutdown(): void {
+  if (shuttingDown) return
+  shuttingDown = true
+  process.stderr.write('telegram channel: shutting down\n')
+  // bot.stop() signals the poll loop to end; the current getUpdates request
+  // may take up to its long-poll timeout to return. Force-exit after 2s.
+  setTimeout(() => process.exit(0), 2000)
+  void Promise.resolve(bot.stop()).finally(() => process.exit(0))
+}
+process.stdin.on('end', shutdown)
+process.stdin.on('close', shutdown)
+process.on('SIGTERM', shutdown)
+process.on('SIGINT', shutdown)
+
 bot.on('message:text', async ctx => {
   await handleInbound(ctx, ctx.message.text, undefined)
 })

external_plugins/telegram/skills/configure/SKILL.md

@@ -77,7 +77,8 @@ offer.
 2. `mkdir -p ~/.claude/channels/telegram`
 3. Read existing `.env` if present; update/add the `TELEGRAM_BOT_TOKEN=` line,
    preserve other keys. Write back, no quotes around the value.
-4. Confirm, then show the no-args status so the user sees where they stand.
+4. `chmod 600 ~/.claude/channels/telegram/.env` — the token is a credential.
+5. Confirm, then show the no-args status so the user sees where they stand.
 
 ### `clear` — remove the token