Track "Skills over MCP" extension (SEP-2640) for future adoption

[mattpodwysocki]

Summary

There's an in-progress MCP extension, "Skills over MCP" (SEP-2640, spec repo:
https://github.com/modelcontextprotocol/ext-skills), being developed by a
dedicated working group. It lets an MCP server expose reusable workflow
instructions (a SKILL.md + supporting files, following the Agent Skills
format) that clients can discover (skills/list/skills/get) and load
on demand via the existing resources/read primitive.

Why this could matter for us

We already have workflow-shaped knowledge that currently only lives as prose
(docs/, tool descriptions, README), which a model has to infer rather than
load explicitly. Candidates for a future skill:

• When to use static_map_image_tool vs render_map_tool
• Chaining isochrone_tool → category_search_tool → render_map_tool for
  coverage/site-selection analysis
• The place_details_tool dual-API logic (Places API vs legacy boundary
  fallback)

We already adopt other MCP extensions this way (@modelcontextprotocol/ext-apps
backs render_map_tool's interactive UI via MapAppUIResource), so this would
follow an established pattern in this codebase.

Current status (as of 2026-09)

• Spec-only — no reference SDK/npm package published yet from the
  ext-skills repo.
• @modelcontextprotocol/sdk@1.30.0 (currently pinned here) has no skills
  support.
• Not actionable yet; revisit once the spec lands in the main MCP repo and
  an SDK/ext-skills package ships (mirroring how ext-apps shipped).

Next steps

• Watch modelcontextprotocol/ext-skills and the SEP-2640 PR for status changes
• Once an SDK package exists, prototype one skill (e.g. static-map vs
  render_map guidance) as a proof of concept
• Re-evaluate whether src/skills/ (mirroring src/resources/ structure)
  is the right home