---
kind: epic
slug: mcp-claim-complete
title: MCP claim_task and complete_task — atomic lifecycle for agents
plan_slug: agent-coordination
status: ready
priority: P2
tenant_id: global
cursor_epic_id: null
updated_at: "2026-06-01"
---

# Epic objective

Add two MCP tools that give a coding agent a shaped lifecycle for a task: `claim_task` (status flip + open `agent_runs` row + return effective workflow prompt) and `complete_task` (status flip + close `agent_runs` row with outcome + tokens).

These replace the current freeform composition where an agent has to call `update_object` repeatedly and pray.

## In scope / out of scope

**In scope**

- New MCP tools `claim_task` and `complete_task` with zod schemas.
- Idempotency rules (don't double-claim).
- Integration with the `agent_runs` table from the previous epic.

**Out of scope**

- A long-running orchestrator (deferred epic).
- A `pause_task` / `resume_task` tool. Resist; you can model that with two `complete_task` calls (`cancelled` + a new claim) until evidence demands it.

## Related tasks

| Task | Link |
|------|------|
| MCP claim_task tool | `./Task-mcp-claim-task-tool.md` |
| MCP complete_task tool | `./Task-mcp-complete-task-tool.md` |

## Dependencies

- Depends on: `Epic-task-as-runnable-unit` (needs `workflow_prompt` and `agent_runs`).

## Acceptance criteria

- [ ] An agent can call `claim_task({ workspace, backlogItemId })` and receive the effective workflow prompt + a `runId`.
- [ ] An agent can call `complete_task({ runId, outcome, tokens, notes })` to finalize.
- [ ] Double-claim of the same task by the same actor returns the existing open run; by a different actor returns an explicit "already claimed by X" error.

## Proposed timeline

| Phase | Window | Notes |
|-------|--------|-------|
| claim_task | Day 1 | Tool + idempotency. |
| complete_task | Day 2 | Tool + run finalization. |