René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"New HTTP serving path (modern + dual-era)","articleBody":"Tracks: #2803\n\nA single HTTP entry that branches: legacy traffic goes to the existing manager untouched; modern traffic goes to a new sessionless path. This is where the sessionless wire mode and the inbound header validation live.\n\n## What's in it\n\n- Single entry point that branches legacy → existing `StreamableHTTPSessionManager` (untouched, including `stateless_http=True`), modern → a new direct path.\n- Sessionless wire mode for modern traffic: no session-id minting, GET/DELETE → 405, disconnect = cancel.\n- The inbound validation ladder lives here (header↔body cross-check, error → HTTP status mapping).\n- Where the `subscriptions/listen` long-lived stream plugs in.\n- What `stateless_http=True` means going forward (current behaviour kept; era is a separate axis).\n\n## Conformance\n\n- `http-header-validation`\n- `http-custom-header-server-validation` (with the helpers from #2900)\n- Together with _Backwards compatibility \u0026 version negotiation_, _Capabilities API + server/discover handler_, _subscriptions/listen_, _Context object (layered, per-request)_: `server-stateless`\n- Once the upstream `server-sessionless` scenario lands in the conformance suite and the conformance version pinned in CI is bumped: `server-sessionless`\n\n## Dependencies\n\n- Depends on: #2892\n\n## References\n\n- [Streamable HTTP](https://modelcontextprotocol.io/specification/draft/basic/transports/streamable-http)\n- [SEP-2567](https://github.com/modelcontextprotocol/modelcontextprotocol/pull/2567)\n- [SEP-2243](https://github.com/modelcontextprotocol/modelcontextprotocol/pull/2243)\n- [server/stateless.ts](https://github.com/modelcontextprotocol/conformance/blob/main/src/scenarios/server/stateless.ts)\n","author":{"url":"https://github.com/maxisbey","@type":"Person","name":"maxisbey"},"datePublished":"2026-06-17T11:11:53.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":1},"url":"https://github.com/2893/python-sdk/issues/2893"}