The MCP Radar

The remote transport since spec 2025-03-26: one endpoint, optional streaming, resumable. Every new remote server should speak it. Deep dive →

Tier-1, spec-steward-maintained, and stable (mcp 1.28.x, @modelcontextprotocol/sdk 1.29.x). Build on these before reaching for anything else. Deep dive →

One npx command, no install, UI plus CLI mode. The CLI mode makes "does the server still expose its tools?" a scriptable CI check. Deep dive →

Fewer, better tools beat endpoint mirrors: definitions eat context (a 106-tool server can cost ~54K tokens at init) and models pick from short menus more reliably.

Since spec 2025-06-18 the MCP server is a resource server with an external authorization server and RFC 8707 resource indicators. This is the sanctioned shape for remote auth — use it as-is.

The separate gofastmcp.com framework (not the FastMCP 1.0 class inside the official SDK) adds auth, proxying, and composition. Productive, but you are one layer away from the spec steward.

Workers plus their agents SDK give you the shortest path to a deployed remote server with OAuth scaffolding. Solid, with the usual platform lock-in trade to weigh.

registry.modelcontextprotocol.io is live but labelled preview; reverse-DNS namespaces and mcp-publisher work today. Publish, but expect churn in the metadata schema.

Stable as of July 2026: SSO to MCP servers through your IdP via ID-JAG, backed by Anthropic, Microsoft, and Okta. Right answer for fleets — client support is still rolling out.

structuredContent plus outputSchema (spec 2025-06-18) turns tool results into typed contracts. Adopt per-tool now; client handling is still uneven enough to keep the text fallback.

Interactive UI delivered over MCP, arriving via the extensions framework in the 2026-07-28 release. Compelling surface; wait for real client coverage before betting a product on it.

Experimental in spec 2025-11-25 and redesigned in the 2026-07-28 RC — the API you prototype against today will move. Prototype, don't ship.

The RC drops the initialize handshake and Mcp-Session-Id, finalising July 28, 2026. Plan the migration now; execute once your SDKs and clients ship it.

Wiring repo, issue-tracker, and deploy servers into CI agents works, but secrets handling and audit trails for non-interactive auth are still house-built.

MCP as an operating-system capability is a strong signal of where this lands, but the consent and isolation model needs to prove itself outside demos.

Deprecated since spec 2025-03-26. Keep a compatibility shim only for clients you cannot upgrade — never start a new server on it.

Auto-converting a spec gives you endpoint-shaped tools, hundreds of them, and a context bill to match. Wrap the workflow, not the API.

Tool poisoning and npm typosquatting campaigns are documented, not hypothetical. Read the tool descriptions and pin versions before granting a server your credentials.

Confused-deputy and token-passthrough failures are exactly the bugs the spec's security doc warns about. Use a vetted library and an external authorization server.

Tool definitions load at init whether or not they're used — context bloat plus an unreviewable capability surface. Split by task domain instead.