@moolam/runtime-harness

Runtime harness core for Sutra companions. Hosts the streaming turn protocol using frozen A P6 harness frames from @moolam/sync-protocol.

Status

StreamingTurnHost has typed emit helpers per A P6 frame kind, a monotonic sequenceIndex allocator, terminateWithError / runGuarded for terminal HARNESS_ERROR, and InMemoryStreamFrameBuffer indexed by sequenceIndex. Last-Event-ID resume (parseLastEventId / resolveStreamResume) replays from the buffer or emits a SEQUENCE_GAP frame with RESYNC_REQUIRED. Integration coverage: disconnect after frame 5 → resume 6..N, and gap fixture index 99. ToolCallParser is an incremental mode state machine (thought / answer / tool_buffer / violation) with pure feed() events. Declared tags are held as fragments across chunk boundaries (PARSER_DECLARED_TAGS + offset fuzz). terminateDeadline() discards open fences / held tags without hanging. A P6 golden-turn fixtures are imported under fixtures/golden-turns/ (loadGoldenTurnCorpus / pnpm golden:sync). Replay with canonical diff: pnpm golden:replay (replayGoldenTurn). Chunk-boundary fuzz CI: pnpm golden:fuzz (prove: pnpm golden:fuzz:prove). Malformed-fence regression goldens (CK-07): pnpm golden:malformed.

Golden replay operator workflow (sync → review diff → land when A P6 changes): docs/golden-replay-operator.md. SandboxSeam + InProcessFakeToolRegistry isolate tool effects (deadline, write-ahead ack, result-schema validation → TOOL_STATUS / tool_response).

A P6 schema

• Types / Zod: @moolam/sync-protocol (harnessFrameSchema)
• Committed JSON Schema: packages/sync-protocol/schemas/HarnessFrame.json (A_P6_HARNESS_FRAME_SCHEMA_PATH)

Last-Event-ID resume (client)

SSE id: equals the frame sequenceIndex (decimal). On reconnect:

1. Send Last-Event-ID: <last seen sequenceIndex>.
2. Host outcome action: "replay": lossless re-delivery of buffered frames with sequenceIndex > N. Attach only — do not restart in-flight tools or re-apply side effects; duplicate Last-Event-ID is idempotent.
3. Host outcome action: "gap": terminal HARNESS_ERROR with code: SEQUENCE_GAP and message advisory RESYNC_REQUIRED (empty buffer, eviction hole, never-issued index, or invalid header). Open a new turn (full resync); do not retry the same Last-Event-ID forever.
4. Absent Last-Event-ID → action: "fresh" (new stream open).
5. Cross-subject / stream mismatch → action: "reject" (no frame leakage).

Anti-cheat charter (training)

training/gym must import this package — never re-implement the parser, sandbox, or correction loop. Binding governance:

training/gym/charter.md

Replay parity (byte-identical canonical frame sequences) is enforced by pnpm --filter @moolam/training-gym parity:check and the gym unit suite.

Scripts

pnpm --filter @moolam/runtime-harness build
pnpm --filter @moolam/runtime-harness test
pnpm --filter @moolam/runtime-harness golden:sync
pnpm --filter @moolam/runtime-harness golden:check
pnpm --filter @moolam/runtime-harness golden:replay
pnpm --filter @moolam/runtime-harness golden:fuzz
pnpm --filter @moolam/runtime-harness golden:malformed
pnpm --filter @moolam/training-gym parity:check
pnpm --filter @moolam/training-gym test

See docs/golden-replay-operator.md for the full sync / review / merge checklist.