[SEP-2575][SEP-2567] 2026-06 stateless support: stdio + InMemory transports#2132
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[SEP-2575][SEP-2567] 2026-06 stateless support: stdio + InMemory transports#2132felixweinberger wants to merge 3 commits into
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v2-stateless
This was referenced May 20, 2026
NEW core/shared/streamDriver.ts: minimal request->response correlator for pipe-shaped client transports (one _pending map keyed by RequestId AND String(id) for _meta.subscriptionId routing). sendAndReceive yields notifications then one response (or indefinite for subscriptions/listen); break/return() sends notifications/cancelled. Send-failure -> synthetic error response (no hang). onMessage routes; close() ends all pending. InMemoryTransport: composes StreamDriver. send() routes via _receive() (driver claims first, falls through to onmessage). close() closes driver. StdioClientTransport: composes StreamDriver. processReadBuffer routes to driver when protocolVersion is unset or stateless. setProtocolVersion() gates back to onmessage for legacy. Satisfies: 2575-R12 (client sendAndReceive contract, pipe transports)
…outers
NEW core/shared/serverStatelessRouter.ts: routeServerStateless() —
per-message branch on isStatelessRequest to StatelessHandlers
{dispatch,listen}; notifications/cancelled aborts matching _inflight
controller.
stdio + InMemory server-side: receive paths route via
routeServerStateless; close() aborts all in-flight.
stdio + InMemory client-side: sendAndReceive threads opts?.signal to
StreamDriver.
Satisfies: 2567-R1 (pipe), 2567-R2
Migrate existing connection-model tests to LegacyTestClient (client.test, server.test, mcp.test, elicitation.test, stateManagementStreamableHttp, taskResumability) — they exercise server-to-client RPCs / oninitialized which require the legacy initialize path. statelessAcceptance.test.ts: add 'Client over InMemory' describe block (auto-probe, legacy negotiate, subscribe demux, MRTR auto-resume). NEW zeroChangeConsumer.test.ts: InMemory describe.each over Server/McpServer ctors + MRTR hardening (accumulate, max-rounds, requestSampling).
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Extends 2026-06 stateless support to stdio + InMemory transports. Additive:
StreamDriver(client-side correlation for pipe transports),serverStatelessRouter(server-side per-message router),sendAndReceiveimpls. Migrates 189 connection-model tests toLegacyTestClient.Motivation and Context
Same SEPs over non-HTTP transports.
How Has This Been Tested?
pnpm test:all(1367). InMemory acceptance scenarios +zeroChangeConsumer(same handler under both protocols).Breaking Changes
None.
Types of changes
Checklist