MCP channel server crashes when receiving inbound Telegram notification

Description

The Telegram channel plugin's MCP server crashes immediately upon receiving an inbound message. The server process exits when it writes a notifications/claude/channel JSON-RPC notification to stdout, suggesting Claude Code closes the server's stdin (or sends a signal) in response.

Environment

• Claude Code: 2.1.80
• macOS Darwin 24.6.0 (Apple Silicon)
• Bun: 1.3.11
• Plugin: telegram@claude-plugins-official v0.0.1

Steps to Reproduce

1. Install telegram plugin: /plugin install telegram@claude-plugins-official
2. Configure token: /telegram:configure <token>
3. Pair and approve a user via /telegram:access pair <code>
4. Set policy to allowlist: /telegram:access policy allowlist
5. /reload-plugins
6. DM the bot from Telegram

Expected Behavior

The inbound message should appear as a <channel source="telegram" ...> notification in the Claude Code session, and the MCP server should remain running.

Actual Behavior

The MCP server process exits immediately after writing the notifications/claude/channel JSON-RPC message to stdout. The server does not crash — Claude Code appears to terminate it.

Evidence

• Outbound works: mcp__plugin_telegram_telegram__reply successfully sends messages to Telegram.
• Server is stable standalone: Running bun server.ts directly (not via MCP) keeps the server alive and correctly outputs the notification JSON to stdout:

``json
{"method":"notifications/claude/channel","params":{"content":"we","meta":{"chat_id":"8036446914","message_id":"24","user":"8036446914","user_id":"8036446914","ts":"2026-03-20T14:00:16.000Z"}},"jsonrpc":"2.0"}
``

• Server crashes under MCP: When spawned by Claude Code as an MCP server, the bun server.ts process disappears within seconds of receiving a Telegram DM. getUpdates returns empty (message was consumed) but no notification reaches the session.
• Confirmed no webhook conflict, no multiple polling sessions, token is valid (getMe succeeds).

Additional Context

• Multiple Claude Code sessions each spawn their own instance of the Telegram MCP server, causing Telegram polling conflicts (409). This is a secondary issue — the primary bug occurs even with a single session.
• The experimental: { 'claude/channel': {} } capability is declared in the server's MCP capabilities.

🤖 Generated with Claude Code