Agentic AI Atlas

II.

Page reference

page:docs-harness-features-backlog-gaps-mcp-channels-gap-mcpc-002

Reading · 2 min

GAP-MCPC-002: MCP Channel Outbound Messaging reference

Send messages from orchestration runs to external channels (Slack, Discord, email)

Pagewiki/docs/harness-features-backlog/gaps/mcp-channels/GAP-MCPC-002.mdOutgoing · 0Incoming · 1

GAP-MCPC-002: MCP Channel Outbound Messaging

Field	Value
Category	mcp-channels
Priority	High
Effort	M
Status	Missing

Description

Send messages from orchestration runs to external channels (Slack, Discord, email) via MCP server tools. Enable processes to notify operators, report progress, and share results through messaging platforms.

CC Implementation

CC's outbound messaging works through MCP tools exposed by channel servers:

slack_schedule_message

client is connected

Slack MCP server exposes slack_send_message, slack_send_message_draft,
Gmail MCP server exposes gmail_create_draft
Calendar MCP server exposes gcal_create_event
The model decides which channel's tool to use based on context
Channel tools are regular MCP tools -- no special plumbing needed once MCP

Current State

No MCP client capability. Cannot invoke external MCP server tools. Processes cannot send messages to external systems.

Target State

Processes can invoke channel MCP tools as effects:

javascript

await ctx.task(defineTask('notify-slack', () => ({
  kind: 'mcp-tool',
  mcpServer: 'slack',
  tool: 'slack_send_message',
  args: { channel: '#orchestration', text: 'Run completed: 128 gaps generated' }
})));

Dependencies

GAP-MCPC-001 -- MCP channel connection
GAP-TOOLS-025 -- MCP client capability

Key Files

Component	Path
CC MCP tools	Available as deferred tools via `mcp__claude_ai_Slack__*`

Recommendation

Phase 3. Once MCP client is working (GAP-TOOLS-025), channel outbound is essentially free -- just invoke the channel server's tools.