# Session migration fixtures
Current fixture baseline schema: **47**.
When `CURRENT_SESSION_EVENT_SCHEMA_VERSION` changes, update this declared
baseline and add or update a fixture that records the new schema's compatibility
expectations. Validate compatibility by running the owning fixture tests, not by
matching schema constants against this documentation.
This directory is reserved for committed binary/text fixtures that exercise
session persistence migrations across released schema versions.
Fixture suites should cover:
* derived index rebuilds
* canonical event-log rewrites
* future-version logs
* corrupt tails / repair-required logs
* idempotent re-apply behavior
* trustworthy unknown event envelopes
The session-package schema-40 fixture verifies that strict current reads still reject the old format. The migration fixture records the epoch-5 development format that reached durable user sessions and is accepted only by the migration path. The schema-41 fixture covers the historical correlated assistant response segment. The schema-42 fixture covers the historical positioned assistant response segment, which strict current reads now reject after the schema-43 model-selection-provenance bump. The schema-43 fixture covers the historical positioned assistant response segment. The schema-44 fixture covers the pre-fidelity-event format. The schema-45 fixture covers the current negotiated model-feature fidelity event, the schema-46 fixture covers the pre-`suspended` runtime-work format that strict current reads now reject, and the schema-47 fixture covers a trustworthy future envelope carrying the `suspended` runtime-work status introduced for paused workflow runs. Schema-39 fixtures cover plugin status, unknown event kinds, malformed JSON, mismatched identity, and sequence gaps. Named interactive-tool, plugin-automation, presentation, and other pre-cutover typed fixtures were removed with their runtime decoders; old stores are rejected by format epoch before normal event replay.
Keep fixtures small, intentional, and documented with the schema version and
expected migration/status outcome.