Week 3 · Lesson 11

MCP harness

“Any harness” means the same orchestrator tools are reachable from Cursor / Claude Code / scripts via MCP.

Time · 1 day
Learn
  • MCP vs REST: same authority, different clients
  • Tool descriptions are UX for the harness agent
  • Never expose raw publish without the same policy gate
Build
  1. Expand server/src/mcp-server.js beyond skills
  2. Add list_posts, get_run, start_run_on_post, get_brand_context
  3. Start a draft from the IDE; confirm it appears in React
Checkpoint

A run started from MCP shows up in the React monitor with the same run_id.

Four notes
  • What problem does this layer solve?
  • What is allowed to call it?
  • What must it never do?
  • How do I observe and test it?