Handshake and session removed
The protocol removes the Mcp-Session-Id header and the initialize handshake. Protocol-level sticky routing is no longer required.
Protocol readiness
MCP 2026-07-28 migration readiness
The MCP 2026-07-28 specification is published. This guide was refreshed against the official specification on 2026-09-11. Protocol publication does not establish that any particular client or server has implemented it. ResolveMesh currently serves the 2025-11-25 protocol through its stable SDK; migration is not yet verified.
Protocol changes
Each request carries the connection context
This revision moves protocol coordination from a session handshake into self-contained requests. Applications may still manage explicit state through ordinary tool arguments.
Identity and capabilities travel with the call
Protocol version, client identity, and client capabilities move into a _meta object on every request.
Operations are visible to HTTP infrastructure
Streamable HTTP requests require Mcp-Method andMCP-Protocol-Version. Named tool, resource, and prompt requests also require Mcp-Name.
Lifecycle and extensions
Deprecated does not mean removed in this release
The formal lifecycle supplies at least 12 months between deprecation and removal. Operators still need to identify dependencies and follow later changelogs.
Roots, Sampling, and Logging
These core features are deprecated under the formal lifecycle; their methods, types, and capability flags remain during the stated deprecation window.
MCP Apps and Tasks
MCP Apps and Tasks are extensions. They remain separate from the stateless protocol core and follow extension-specific lifecycles.
Authorization alignment
The revision moves authorization closer to common OAuth and OpenID Connect deployment patterns.
Operator checklist
Inventory before changing production traffic
Work from installed servers to client releases, then keep the official changelog in the operating loop.
Inventory servers
Record every installed server, transport, owner, and deployed SDK version before planning a migration.
Find session dependencies
Identify code, gateways, and tests that depend on Mcp-Session-Id, initialize, or sticky routing.
Review deprecated features
Check Roots, Sampling, and Logging usage against the formal lifecycle and document any replacement work.
Track client releases
Verify installed client versions and follow official changelogs alongside the published specification. Preserve a tested fallback for clients still using earlier protocol revisions.
Client readiness
No catalog client is marked ready without owner evidence
Protocol support has not been verified for these clients. This table changes only after a reviewed, client-owner source and version-specific evidence support a more specific statement.
| Client | Readiness | Evidence note |
|---|---|---|
| ChatGPT web | Unknown | Version-specific protocol support not yet verified |
| ChatGPT desktop | Unknown | Version-specific protocol support not yet verified |
| Claude Code | Unknown | Version-specific protocol support not yet verified |
| Cursor | Unknown | Version-specific protocol support not yet verified |
| Codex | Unknown | Version-specific protocol support not yet verified |
| Gemini CLI | Unknown | Version-specific protocol support not yet verified |
| VS Code | Unknown | Version-specific protocol support not yet verified |
| Windsurf | Unknown | Version-specific protocol support not yet verified |
| GitHub Copilot coding agent | Unknown | Version-specific protocol support not yet verified |
ResolveMesh surfaces
Keep protocol readiness separate from pair compatibility
The public catalog records reviewed client and tool requirements. It does not turn protocol publication into a compatibility claim.
Compare all pairs
Review the 9-client by 10-tool evidence matrix.
Open compatibilityInspect canonical examples
Read the dated receipts for Codex with GitHub MCP and Claude Code with GitHub MCP.
Open the Codex pair Open the Claude Code pairRead machine receipts
Query the approved compatibility-change ledger without page markup.
Open the JSON ledgerFounder-reviewed alerts
Request a Codex-wide compatibility watch
This client-wide request matches approved changes across the open tool dimension. It creates no account, monitoring promise, alert-delivery commitment, or charge.
Primary sources
References
Both protocol-maintainer posts were checked 2026-07-13. This guide paraphrases only the bounded fact set recorded in the approved implementation contract.
MCP 2026-07-28 specification changelog
Published protocol changes, including stateless requests, discovery, extensions, and deprecations; reviewed 2026-09-11.
Read the primary sourceMCP 2026-07-28 Streamable HTTP
Required request headers, transport behavior, and backward compatibility; reviewed 2026-09-11.
Read the primary source