GAP-MCPC-001: MCP Channel Integration (Inbound Messaging)

Description

Support MCP servers as messaging channels (Slack, Discord, Telegram, iMessage, email) that can push inbound messages into orchestration runs. A "channel" is an MCP server that sends notifications/claude/channel notifications for inbound messages and exposes tools for outbound messages.

CC Implementation

CC's channel system (src/services/mcp/channelNotification.ts):

• MCP servers declare channel capability in capabilities.experimental['claude/channel']
• Inbound messages arrive as notifications/claude/channel notifications
• Messages wrapped in <channel source="..." sender="...">content</channel> XML tags
• SleepTool polls hasCommandsInQueue() and wakes within 1s to process inbound
• The model sees the source channel and decides which tool to reply with
• Channel allowlist (channelAllowlist.ts) controls which channels are active
• Channel entries have: serverName, displayName, channelId, channelType
• Requires explicit opt-in (not default-enabled)
• Feature-gated: tengu_harbor / KAIROS_CHANNELS

Current State

Babysitter has mcp:serve which exposes babysitter as an MCP SERVER. But there is no MCP CLIENT capability for connecting to external MCP servers as channels. No channel notification handling. No inbound message queue. No channel allowlist.

Target State

Babysitter can connect to MCP servers that act as messaging channels. Inbound messages from channels are: 1. Queued as journal events (CHANNEL_MESSAGE type) 2. Routed to active runs based on channel binding 3. Available as context during breakpoint decisions 4. Trigger run wake-up if sleeping

This enables operators to receive breakpoint notifications on Slack and approve/reject from their phone.

Dependencies

• GAP-TOOLS-025 -- MCP client capability

Note: MCPC-002 and MCPC-003 depend on MCPC-001, not the other way around.

Key Files

Recommendation

Phase 2-3. Requires MCP client capability first (GAP-TOOLS-025). Then implement channel notification handler and message queue. Start with Slack as the first channel (already has an MCP server in the CC ecosystem).