Changelog

Each release is a dated, immutable OpenAPI file in openapi/. Entries describe contract changes.

Unreleased

• Breaking: the contract fixes no endpoint path. The operation moves from paths./v1/systemone to components.pathItems.SystemOne, served as POST at a URL the implementer chooses. Clients take the full endpoint URL as configuration.
• model stays required when an implementer serves a single model at its URL, and an implementer rejects a model it does not serve.

2026-11-07

First release: openapi/2026-11-07.json.

• POST /v1/systemone with TypeSafe’s request, response, and decision question types (noul, choice, score, box). Image assets also accept the webp format.
• Optional request reference_date, and optional response truncated and state_text. When the state was truncated, state_text may be only the portion the model read. Implementers may reject oversized input instead of truncating it.
• Error envelope with standard codes unsupported_question_type and unsupported_parameter.
• Extraction question and answer types: text, number, date, time, datetime, duration, list, estimate, and forecast.
• Extension question and answer types named owner:type, kept apart from the core types in SystemOneCoreQuestion and SystemOneCoreAnswer.
• SPEC.md with the normative rules: answer guarantees, truncation and state_text, the standard errors, extension types and their promotion to core, versioning, and compatibility with TypeSafe.
• Spans count Unicode code points. A value not read from the state text, such as one read from an image, has no span: span is absent or null, and a list’s spans entry is null.
• time answers are HH:MM or HH:MM:SS. forecast answers are a steps array; steps have no quantiles. Estimate quantiles are present only when the question requests them, and a date estimate’s mean is a date.
• choice must be one of the criteria and should be the most likely one.