# H/M MCP 2026 Transition Lab

H/M MCP 2026 Transition Lab is a free browser-local, declaration-based migration map from MCP `2025-11-25` to the locked `2026-07-28` release candidate.

- Human interface: https://hogarmas.net/mcp-2026/
- Check catalog: https://hogarmas.net/mcp-2026/checklist.json
- Export schema: https://hogarmas.net/mcp-2026/schema.json
- Ruleset: `2026-07-21.1`
- Assessment schema: `hm.mcp-2026-transition.assessment.v1`
- Export schema: `hm.mcp-2026-transition.v1`

## Release status

The target is not represented as a final specification.

- Source baseline: `2025-11-25`
- Target: `2026-07-28`
- Target status: `locked-release-candidate`
- Release candidate locked: `2026-05-21`
- Expected final publication: `2026-07-28`
- Assessed as of: `2026-07-21`
- Final specification verified by this ruleset: `false`

The release candidate may still differ from the final publication. Re-run the assessment after the final specification and matching conformance assets are published.

## Inputs

The browser asks only for implementation context and tri-state answers.

Context fields:

- transport: `streamable-http`, `sse`, `stdio`, `other`, or `unknown`
- access mode: `public`, `protected`, or `unknown`
- feature use: `yes`, `no`, or `unknown` for tools, tasks, elicitation, subscriptions, extensions, and Dynamic Client Registration

Each check answer is one of:

- `yes`
- `no`
- `unknown`
- `not-applicable`, computed from context

No project name, repository, endpoint, source code, traffic capture, dependency list, or credential is requested.

## Decision states

- `migration-blocked`: at least one critical or high-priority answer conflicts with the target behavior.
- `changes-required`: no blocker is declared, but one or more medium-priority migration actions remain.
- `insufficient-evidence`: no blocker or review action is declared, but applicable answers remain unknown.
- `declared-ready`: every applicable answer matches this release-candidate checklist.

`declared-ready` is not runtime compatibility certification.

## Covered transition surfaces

The 28 deterministic checks cover:

1. removal of initialize/initialized and protocol-level sessions
2. removal of `Mcp-Session-Id`
3. required `Mcp-Method` and `Mcp-Name` routing headers
4. per-request protocol, capability, client, and server identity metadata
5. `server/discover` and unsupported-version behavior
6. request-scoped server-to-client interactions
7. `input_required`, `resultType`, and multi round-trip retries
8. `subscriptions/listen` and removal of legacy subscription paths
9. `ttlMs`, `cacheScope`, deterministic tool order, and error-code changes
10. removal of SSE resumability and deprecation of HTTP+SSE
11. Tasks extension and reverse-DNS extension negotiation
12. deprecation of Roots, Sampling, and Logging for new implementations
13. JSON Schema 2020-12 and bounded external-reference handling
14. authorization issuer validation, application type, credential binding, and Client ID Metadata Documents
15. W3C Trace Context propagation

## Output privacy

The JSON and Markdown exports are source-minimized.

- Raw code included: `false`
- Project name included: `false`
- Repository included: `false`
- Endpoint included: `false`
- Credential included: `false`
- Metric payload includes answers: `false`
- Synthetic activity presented as real: `false`

The input hash is calculated locally from normalized declarations. It is not sent as part of H/M content metrics.

## Explicit limitations

- The assessment is declaration-only.
- No source code or dependency is inspected.
- No network request or runtime exchange is observed.
- No official SDK or conformance suite is run.
- The final `2026-07-28` specification is not verified by this ruleset.
- The release candidate may change.
- No compatibility certification is produced.

## Primary sources

- Release candidate announcement: https://blog.modelcontextprotocol.io/posts/2026-07-28-release-candidate/
- Draft changelog: https://modelcontextprotocol.io/specification/draft/changelog
- Draft specification: https://modelcontextprotocol.io/specification/draft
- Stable baseline: https://modelcontextprotocol.io/specification/2025-11-25/basic

## Related tools

- Inspect an MCP registry and authorization contract before connection: https://hogarmas.net/mcp-trust/
- Audit agent permissions: https://hogarmas.net/agent-scope/
- Map agent attack paths: https://hogarmas.net/agent-risk-atlas/