MCP channel notifications intermittently dropped

Summary

MCP channel notifications from the Telegram plugin are intermittently dropped — the bot receives messages from Telegram and calls mcp.notification({ method: 'notifications/claude/channel', ... }), but Claude Code doesn't surface them to the conversation.

Reproduction

1. Set up Telegram channel plugin (claude --channels plugin:telegram@claude-plugins-official)
2. Pair a Telegram user via /telegram:access pair <code>
3. Send multiple messages from Telegram in sequence

Observed behavior

• Some messages arrive in Claude Code, others are silently dropped
• No pattern tied to message content (plain text like "Um", "Clear", "How? it didn't work" all dropped)
• Outbound replies (tool calls to reply) work 100% of the time
• The bot process is healthy — TCP connections to Telegram are ESTABLISHED, bot.catch error handler is not firing
• The mcp.notification() call has a .catch() handler that logs to stderr — no errors observed
• Drops happen regardless of whether Claude Code is mid-generation or idle at the prompt
• Messages sometimes come through in bursts (6 consecutive successes), then suddenly stop (3+ consecutive drops)

Environment

• macOS Darwin 25.3.0 (aarch64)
• Claude Code via claude --channels plugin:telegram@claude-plugins-official
• Telegram plugin from claude-plugins-official
• Bot framework: Grammy (long-polling, default settings)
• Runtime: Bun

Diagnosis

• Confirmed the bot is not in static mode (re-reads access.json each message)
• Confirmed no duplicate bot processes competing for getUpdates (an earlier zombie was present but exited before the test sequence)
• Confirmed gate() returns deliver for the allowlisted sender
• Confirmed handleInbound() reaches the mcp.notification() call (outbound ack reactions fire)
• The drop appears to be on the Claude Code side — the MCP notification is sent over stdio but not surfaced

Expected behavior

All notifications/claude/channel notifications from the MCP server should be surfaced to the conversation.