# MCP Round 4 Plan

## Summary

Round 4 expands `spool-mcp` from lifecycle-only tooling into a retrieval gateway that exposes the existing context and wakeup core through MCP.

The work is sequenced in this order:

1. add retrieval MCP tools on top of `app` and `memory_gateway`
2. keep response payloads structured and aligned with existing domain objects
3. verify both lifecycle and retrieval tools through the same MCP server

## Key Changes

### Retrieval tools

- add `memory_search`
- add `memory_explain`
- add `memory_wakeup`
- reuse existing route input concepts:
  - `task`
  - `cwd`
  - optional `files`
  - optional `target`
  - optional `format`
  - optional `profile` for wakeup

### MCP server shape

- keep a single `spool-mcp` binary
- continue using newline-delimited JSON-RPC over stdio
- keep lifecycle and retrieval tools in one shared tool registry

## Test Plan

- handler tests for retrieval tools
- process smoke test covering:
  - `initialize`
  - `tools/list`
  - lifecycle tool call
  - retrieval tool call

## Assumptions

- this round does not rename existing lifecycle tool names
- this round does not add MCP prompts/resources
- this round does not add write metadata yet

## Completion Status

Last checked: `2026-04-11`

Completed in this round:

- added retrieval MCP tools:
  - `memory_search`
  - `memory_explain`
  - `memory_wakeup`
- kept lifecycle and retrieval tools on the same MCP server
- added retrieval handler coverage and expanded MCP smoke coverage
- verification completed with full test and check passes

Checked for omissions against this plan:

- no missed items inside the scoped implementation baseline
- lifecycle tool names remain unchanged
- MCP prompts/resources remain intentionally deferred
- write metadata remains intentionally deferred
