Focused MCP Surface
Planu used to document a Core / Domain / Power tool-loading model. Starting with v3.9.0, the public MCP surface is simpler: 22 official SDD tools, always focused on the same lifecycle.
Why This Changed
Large MCP tool catalogs increase token cost and make agents less reliable. The model sees too many options and can choose tools that are adjacent to the workflow but not essential.
Planu now keeps the MCP surface fixed and small:
| Surface | Tools sent |
|---|---|
| Official MCP | 22 |
| Advanced workflows | Skills, CLI, and internal pipelines |
The Official Loop
intent → questions → spec → challenge → readiness → approval → handoff → validate → done
The agent does not need hundreds of tool schemas to follow this loop. It needs a clear contract and strong gates.
What Happened to Advanced Capabilities?
Advanced capabilities still exist where they create value:
- Skills encode repeatable workflows.
- CLI commands handle maintenance and release operations.
- Internal role pipelines apply Product, Architecture, Security, QA, Implementation, and Validation reviews.
- Project rules keep host-specific behavior consistent without expanding the MCP tool list.
Cross-links
- Tools Reference — the 22 official MCP tools.
- Skills & Extensions — repeatable workflows loaded on demand.
- Lean Spec Format — compact specs for better model attention.