[BUG] Discord channel plugin: MCP connected but inbound DMs never delivered to session (detailed root cause analysis)

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet (related: #36460, #36503)
• [x] This is a single bug report
• [x] I am using the latest version of Claude Code

What's Wrong?

The Discord channel plugin (discord@claude-plugins-official) connects to Discord Gateway successfully, MCP tools work (fetch/reply), but inbound DMs are never pushed to the Claude Code session. The bot appears online (green) in Discord, manual fetch_messages and reply work perfectly, but the session never receives automatic notifications when a user sends a DM.

Additionally, the status bar shows "Channels are not currently available" even though the MCP server is functional.

What Should Happen?

When a user DMs the bot, the message should be delivered to the active Claude Code session as an inbound notification, triggering an automatic response.

Root Cause Analysis

Through extensive debugging, I identified three separate issues compounding into this behavior:

1. DISABLE_TELEMETRY env var blocks channels entirely

If DISABLE_TELEMETRY is set to any value (even "0" or "false"), the channels feature is disabled. The check appears to be existence-based rather than value-based.

Evidence:

• With DISABLE_TELEMETRY=true: status bar shows "Channels are not currently available"
• With DISABLE_TELEMETRY unset: no error (but inbound still does not work, see issue 2 and 3)

Complication: Many developers set DISABLE_TELEMETRY=true in shell configs for privacy across various tools. This common pattern should not break channel functionality.

Suggestion: Use a Claude-specific variable like CLAUDE_CODE_DISABLE_CHANNELS=true instead of piggybacking on a generic telemetry flag.

2. MCP server marked "failed" due to stderr DeprecationWarning

The Discord plugin MCP server outputs a DeprecationWarning from discord.js to stderr on startup:

discord channel: gateway connected as HypeproofClaude#6812
DeprecationWarning: The ready event has been renamed to clientReady...

Claude Code interprets any stderr output as a server error, marking the MCP as "failed" in /plugin UI. This is the known issue from #17653.

Evidence:

• claude --debug --debug-file /tmp/debug.log mcp list shows: plugin:discord:discord: Connected
• But /plugin UI shows: discord MCP - failed

Redirecting stderr (2>/dev/null) in package.json makes the "failed" indicator disappear, but may break MCP communication.

3. Inbound notifications not delivered even when MCP is connected

Even after resolving issues 1 and 2, inbound DMs are never delivered to the session. The MCP tools work fine for manual operations:

• fetch_messages(channel) returns messages correctly
• reply(chat_id, text) sends messages correctly
• But channel source="discord" notification never appears in session

This appears to be the core issue: the channels subsystem does not subscribe to MCP server notifications even when the server is running and connected.

Error Messages/Logs

Debug log from claude --debug --debug-file:

MCP server "plugin:discord:discord": Starting connection with timeout of 30000ms
MCP server "plugin:discord:discord": Successfully connected to undefined server in 2040ms
MCP server "plugin:discord:discord": Connection established with capabilities: {"hasTools":true,"hasPrompts":false,"hasResources":false,"hasResourceSubscribe":false,"serverVersion":{"name":"discord","version":"1.0.0"}}

Status bar message: Channels are not currently available

Steps to Reproduce

1. Install Discord plugin: /plugin install discord@claude-plugins-official
2. Configure token: /discord:configure <bot-token>
3. Ensure bun is installed and in PATH
4. Start session: claude --channels plugin:discord@claude-plugins-official
5. Observe status bar: "Channels are not currently available" (if DISABLE_TELEMETRY is set)
6. Even after unsetting DISABLE_TELEMETRY and restarting:

• Bot appears online in Discord (green indicator)
• mcp list shows Connected
• /plugin shows MCP failed (due to stderr)
• DM the bot: no response, no notification in session
• Manual fetch_messages: messages visible
• Manual reply: message sent successfully

Claude Code Version

2.1.81 (Claude Code)

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

VS Code integrated terminal (Antigravity fork) + Terminal.app, zsh

Is this a regression?

I don't know

Additional Information

• Model: Opus 4.6 (1M context)
• macOS: Darwin 24.6.0
• Bun: 1.3.11
• Discord.js: 14.25.1
• Plugin version: discord@claude-plugins-official 0.0.2
• Related issues: #36460 (Max plan channels unavailable), #36503 (inbound notifications ignored), #17653 (stderr causes MCP "failed")
• The DISABLE_TELEMETRY workaround was found via community reports on X (Twitter)
• The MCP "failed" indicator from stderr is cosmetic but confusing
• The core issue (inbound not delivered) persists regardless of the other two issues being resolved