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/telegram/server.ts

@@ -304,7 +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'.
@@ -341,7 +341,7 @@ const mcp = new Server(
     instructions: [
       'The sender reads Telegram, not this session. Anything you want them to see must go through the reply tool — your transcript output never reaches their chat.',
       '',
-      'Messages from Telegram arrive as <channel source="telegram" chat_id="..." message_id="..." user="..." ts="...">. If the tag has an image_path attribute, Read that file — it is a photo the sender attached. If the tag has attachment_file_id, call download_attachment with that file_id to fetch the file, then Read the returned path. Reply with the reply tool — pass chat_id back. Use reply_to (set to a message_id) only when replying to an earlier message; the latest message doesn\'t need a quote-reply, omit reply_to for normal responses.',
+      'Messages from Telegram arrive as <channel source="telegram" chat_id="..." message_id="..." user="..." ts="...">. If the tag has an image_path attribute, Read that file — it is a photo the sender attached. Reply with the reply tool — pass chat_id back. Use reply_to (set to a message_id) only when replying to an earlier message; the latest message doesn\'t need a quote-reply, omit reply_to for normal responses.',
       '',
       'reply accepts file paths (files: ["/abs/path.png"]) for attachments. Use react to add emoji reactions, and edit_message to update a message you previously sent (e.g. progress → result).',
       '',
@@ -389,17 +389,6 @@ mcp.setRequestHandler(ListToolsRequestSchema, async () => ({
         required: ['chat_id', 'message_id', 'emoji'],
       },
     },
-    {
-      name: 'download_attachment',
-      description: 'Download a file attachment from a Telegram message to the local inbox. Use when the inbound <channel> meta shows attachment_file_id. Returns the local file path ready to Read. Telegram caps bot downloads at 20MB.',
-      inputSchema: {
-        type: 'object',
-        properties: {
-          file_id: { type: 'string', description: 'The attachment_file_id from inbound meta' },
-        },
-        required: ['file_id'],
-      },
-    },
     {
       name: 'edit_message',
       description: 'Edit a message the bot previously sent. Useful for progress updates (send "working…" then edit to the result).',
@@ -491,24 +480,6 @@ mcp.setRequestHandler(CallToolRequestSchema, async req => {
         ])
         return { content: [{ type: 'text', text: 'reacted' }] }
       }
-      case 'download_attachment': {
-        const file_id = args.file_id as string
-        const file = await bot.api.getFile(file_id)
-        if (!file.file_path) throw new Error('Telegram returned no file_path — file may have expired')
-        const url = `https://api.telegram.org/file/bot${TOKEN}/${file.file_path}`
-        const res = await fetch(url)
-        if (!res.ok) throw new Error(`download failed: HTTP ${res.status}`)
-        const buf = Buffer.from(await res.arrayBuffer())
-        // file_path is from Telegram (trusted), but strip to safe chars anyway
-        // so nothing downstream can be tricked by an unexpected extension.
-        const rawExt = file.file_path.includes('.') ? file.file_path.split('.').pop()! : 'bin'
-        const ext = rawExt.replace(/[^a-zA-Z0-9]/g, '') || 'bin'
-        const uniqueId = (file.file_unique_id ?? '').replace(/[^a-zA-Z0-9_-]/g, '') || 'dl'
-        const path = join(INBOX_DIR, `${Date.now()}-${uniqueId}.${ext}`)
-        mkdirSync(INBOX_DIR, { recursive: true })
-        writeFileSync(path, buf)
-        return { content: [{ type: 'text', text: path }] }
-      }
       case 'edit_message': {
         assertAllowedChat(args.chat_id as string)
         const edited = await bot.api.editMessageText(
@@ -536,6 +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)
 })
@@ -566,94 +555,10 @@ bot.on('message:photo', async ctx => {
   })
 })
 
-bot.on('message:document', async ctx => {
-  const doc = ctx.message.document
-  const name = safeName(doc.file_name)
-  const text = ctx.message.caption ?? `(document: ${name ?? 'file'})`
-  await handleInbound(ctx, text, undefined, {
-    kind: 'document',
-    file_id: doc.file_id,
-    size: doc.file_size,
-    mime: doc.mime_type,
-    name,
-  })
-})
-
-bot.on('message:voice', async ctx => {
-  const voice = ctx.message.voice
-  const text = ctx.message.caption ?? '(voice message)'
-  await handleInbound(ctx, text, undefined, {
-    kind: 'voice',
-    file_id: voice.file_id,
-    size: voice.file_size,
-    mime: voice.mime_type,
-  })
-})
-
-bot.on('message:audio', async ctx => {
-  const audio = ctx.message.audio
-  const name = safeName(audio.file_name)
-  const text = ctx.message.caption ?? `(audio: ${safeName(audio.title) ?? name ?? 'audio'})`
-  await handleInbound(ctx, text, undefined, {
-    kind: 'audio',
-    file_id: audio.file_id,
-    size: audio.file_size,
-    mime: audio.mime_type,
-    name,
-  })
-})
-
-bot.on('message:video', async ctx => {
-  const video = ctx.message.video
-  const text = ctx.message.caption ?? '(video)'
-  await handleInbound(ctx, text, undefined, {
-    kind: 'video',
-    file_id: video.file_id,
-    size: video.file_size,
-    mime: video.mime_type,
-    name: safeName(video.file_name),
-  })
-})
-
-bot.on('message:video_note', async ctx => {
-  const vn = ctx.message.video_note
-  await handleInbound(ctx, '(video note)', undefined, {
-    kind: 'video_note',
-    file_id: vn.file_id,
-    size: vn.file_size,
-  })
-})
-
-bot.on('message:sticker', async ctx => {
-  const sticker = ctx.message.sticker
-  const emoji = sticker.emoji ? ` ${sticker.emoji}` : ''
-  await handleInbound(ctx, `(sticker${emoji})`, undefined, {
-    kind: 'sticker',
-    file_id: sticker.file_id,
-    size: sticker.file_size,
-  })
-})
-
-type AttachmentMeta = {
-  kind: string
-  file_id: string
-  size?: number
-  mime?: string
-  name?: string
-}
-
-// Filenames and titles are uploader-controlled. They land inside the <channel>
-// notification — delimiter chars would let the uploader break out of the tag
-// or forge a second meta entry.
-function safeName(s: string | undefined): string | undefined {
-  return s?.replace(/[<>\[\]\r\n;]/g, '_')
-}
-
 async function handleInbound(
   ctx: Context,
   text: string,
   downloadImage: (() => Promise<string | undefined>) | undefined,
-  attachment?: AttachmentMeta,
 ): Promise<void> {
   const result = gate(ctx)
 
@@ -701,13 +606,6 @@ async function handleInbound(
         user_id: String(from.id),
         ts: new Date((ctx.message?.date ?? 0) * 1000).toISOString(),
         ...(imagePath ? { image_path: imagePath } : {}),
-        ...(attachment ? {
-          attachment_kind: attachment.kind,
-          attachment_file_id: attachment.file_id,
-          ...(attachment.size != null ? { attachment_size: String(attachment.size) } : {}),
-          ...(attachment.mime ? { attachment_mime: attachment.mime } : {}),
-          ...(attachment.name ? { attachment_name: attachment.name } : {}),
-        } : {}),
       },
     },
   })