MCP 2026-07-28

CURRENT Confidence: High (1.00)

Specification revision · released 2026-07-28

MCP 2026-07-28 is the current stable revision of the Model Context Protocol specification, released 2026-07-28. 2 of 2 verified entities support it.

What is MCP specification revision 2026-07-28?

MCP 2026-07-28 is the current stable revision of the Model Context Protocol specification, released 2026-07-28.

Which servers and clients support MCP 2026-07-28?

2 entities have a verified support record against 2026-07-28: 2 supported, 0 partial, 0 not supported. Each record links its evidence URL and check date.

The largest revision since the protocol launched: the core becomes stateless (the initialize handshake and protocol-level sessions are removed), server/discover is introduced, Multi Round-Trip Requests replace server-initiated requests, routing headers and cacheable list results land, and a formal extensions framework and 12-month deprecation policy are adopted.

What changed in MCP 2026-07-28?

Stateless protocol core: initialize/initialized handshake and the Mcp-Session-Id header removed; every request carries protocol version, client identity, and capabilities in _meta
New server/discover RPC (servers MUST implement it) advertises supported protocol versions, capabilities, and identity
Multi Round-Trip Requests (MRTR) replace server-initiated elicitation/create, sampling/createMessage, and roots/list
Mcp-Method and Mcp-Name headers required on Streamable HTTP requests for header-based routing
Cacheable list results: ttlMs and cacheScope required on tools/list, prompts/list, resources/list, resources/read
subscriptions/listen replaces the HTTP GET stream and resources/subscribe
Tasks move to the io.modelcontextprotocol/tasks extension; extensions framework formalized (Tasks, MCP Apps, Enterprise Managed Authorization)
Authorization hardening: RFC 9207 issuer validation, credentials bound to issuer, Dynamic Client Registration deprecated in favor of Client ID Metadata Documents
Roots, Sampling, Logging, and the legacy HTTP+SSE transport deprecated under a formal feature lifecycle with a twelve-month minimum removal window

MCP 2026-07-28 is the current stable revision of the Model Context Protocol specification and its largest revision to date. The protocol core becomes stateless: the initialize handshake and protocol-level sessions are retired, every request is self-contained, and any request can land on any server instance behind a plain load balancer. Servers must implement the new server/discover RPC; clients may call it for up-front capability discovery but are not required to.

Server-initiated requests are redesigned as Multi Round-Trip Requests: a tool that needs mid-call input returns an input_required result and the client retries the original call with the answers attached. Streamable HTTP requests must carry the Mcp-Method and Mcp-Name headers, list results carry cache hints, and change notifications consolidate into a single subscriptions/listen stream.

Roots, Sampling, Logging, and the legacy HTTP+SSE transport are deprecated under the newly adopted feature lifecycle policy, which guarantees a twelve-month minimum window before removal. Tasks graduate into the formal extensions framework alongside MCP Apps and Enterprise Managed Authorization. The four Tier 1 SDKs (TypeScript, Python, Go, C#) shipped support on release day.

Which servers and clients are verified against MCP 2026-07-28?

Entity	Type	Status	Last checked	Evidence
GitHub MCP Server	server	Supported	2026-08-04	Source
Vercel MCP	server	Supported	2026-08-04	Source

How was this verified, and what are the sources?

Verified 2026-08-04 · method: spec-changelog · confidence 1.00 (High).