Deployed contract status

The documentation describes the current contract, and api.aethis.ai serves engine 0.59.3 — the build that contract describes. Everything on these pages is live; nothing on them is waiting on a deploy. Every response carries engine_version. Check it to see which build served you:

curl -sS -X POST https://api.aethis.ai/api/v1/public/decide \
  -H "Content-Type: application/json" \
  -d '{
    "ruleset_id": "aethis/uk-fsm/child-eligibility",
    "field_values": { "child.age": 10, "child.school_type": "state_funded" }
  }' | python3 -c 'import sys,json; print(json.load(sys.stdin)["engine_version"])'

aethis-core@0.59.3

What changed at 0.49.1

Earlier revisions of this page listed contract rows that the deployed engine did not yet serve. All of them now do. Each row below was re-verified against api.aethis.ai on 2026-07-28:

Behaviour	Status on `api.aethis.ai` (0.49.1)
Resolved identity: immutable `ruleset_id`, a real `ruleset_version`, `content_digest`	Served. `/decide` and `/explain` both return `ruleset_version` (e.g. `"v2"`) and `content_digest`
Blocking `field_errors` force `decision: "undetermined"`	Served. An unusable input returns `undetermined` with the offending field in `field_errors` and `missing_fields`
An undefined top-level request key returns `422 extra_forbidden`	Served. An unknown body key is rejected, not silently ignored
`X-Aethis-Records-Omitted` on catalogue reads	Served. `GET /rulesets` returns the header (`0` when nothing was omitted)
Publish-validated `source_references[]` on criteria	Served. `/explain` returns `source_refs` and `source_references` on every criterion. They are `null` on the first-party showcase rulesets, which do not yet declare citation keys — see Provenance and citations
Anonymous cross-origin access scoped per route and method	Served. The open surface answers any origin with `GET, POST, OPTIONS` and no credentials; every other route reflects only first-party origins

What to guard for anyway

Nothing here is version-gated any more, but two habits stay worth keeping:

Check field_errors yourself rather than relying on the engine to force undetermined for you — good practice regardless of which build answers.
Treat source_references as optional. null and [] both mean “this criterion carries no verified reference”, never “verification failed”.

If a call ever returns an engine_version below 0.49.1, you are talking to a different deployment — check the host before debugging the contract.

Coordinated release candidate: frozen rulebook members

Core candidate e71e758 adds an additive release object for a composed rulebook decision. It is not a deployed capability claim: do not send release_id to api.aethis.ai or rely on this response shape until the production OpenAPI and an observed production response confirm it. When deployed, a caller will be able to pin a composed decision with release_id. The response will retain the selected release_id, its existing content_identity, and a members mapping. Each member records the resolved section, ruleset identity, version identity and content digest used for that release. This is stronger than retaining a composition hash or member IDs alone: it makes a replay auditable against the exact member bytes.

{
  "release": {
    "release_id": "<immutable release id>",
    "content_identity": "<composition identity>",
    "members": {
      "<section_id>": {
        "ruleset_id": "<resolved ruleset id>",
        "version_id": "<immutable member version id>",
        "content_digest": "sha256:<member bytes>"
      }
    }
  }
}

Treat this as the coordinated OpenAPI candidate shape. The deployment gate is the live OpenAPI plus a pinned decision/replay observation; a merged core pull request alone is not evidence that public production serves it.

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Deployed contract status

What changed at 0.49.1

What to guard for anyway

Coordinated release candidate: frozen rulebook members

​What changed at 0.49.1

​What to guard for anyway

​Coordinated release candidate: frozen rulebook members

What changed at 0.49.1

What to guard for anyway

Coordinated release candidate: frozen rulebook members