agents-mcp

# MCP (Model Context Protocol) Use this skill to decide whether MCP is the right abstraction, configure existing servers in Claude Code or Codex, or build a narrow custom server when repeated agent workflows justify it. Protocol baseline: **`2026-07-28` is the current spec — it shipped on 2026-07-28** (`https://modelcontextprotocol.io/specification/2026-07-28/changelog`), superseding `2025-11-25`. It is a fundamental redesign, not an increment: - **Stateless protocol.** The `initialize`/`notifications/initialized` handshake and the `Mcp-Session-Id` header are removed (SEP-2567, SEP-2575). Every request carries its protocol version and client capabilities in `_meta`; a mandatory `server/discover` RPC advertises supported versions and identity. Servers needing cross-call state mint explicit handles passed as ordinary tool arguments. - **Roots, Sampling, and Logging are deprecated** (SEP-2577) — still functional, but new implementations should not adopt them. Migrate to tool-parameter directories / resource URIs, direct LLM provider API calls, and stderr or OpenTelemetry respectively. - **Server-initiated requests are gone.** `roots/list`, `sampling/createMessage`, and `elicitation/create` are replaced by the Multi Round-Trip Requests (MRTR) pattern: the server returns `resultType: "input_required"` with `inputRequests`, and the client retries the original request carrying `inputResponses`. - **Transport changes.** The HTTP GET endpoint and `resources/subscribe`/`unsubscribe`...