JOE-1896)¶

Boundary: contracts for the 0.0.x line. Pre-1.0 change stays predictable and honest. For the 1.0 RC freeze inventory (frozen surfaces, break-reset policy, automated checks), see rc-freeze.md.

Classification¶

Surface	Class	Notes
`TranscriptionError` / `AurumError`, `ErrorCategory`	stable-at-0.x	Category ids frozen; variants may grow under non-exhaustive policy
`Config`, `Config::validate`, `effective_diagnostic`	stable-at-0.x	Secrets always redacted in Debug/diagnostic
`ValidatedConfig`, `AurumEngine`	provisional → stable-at-0.x	Preferred library entry; owns governor/metrics/STT(+TTS) pools
`SttContextPool` / `TtsSessionPool`	provisional	Engine-local by default; process-global helpers for CLI
`SecretString`	stable-at-0.x	Debug/Display never expose payload
`Segment` (private fields + accessors)	stable-at-0.x	`try_new` / `validate` / getters (JOE-1786)
`SampleRateHz` / `FiniteDurationSecs` / `ModelId`	provisional	Domain primitives
`TranscriptionResult::try_local` / `try_openrouter`	stable-at-0.x	Fail-closed builders
Process-global STT/TTS pools	legacy shared default	Used only when constructing providers without an engine
`SttResultDto` `schema_version = 1`	stable-at-0.x	Unknown future fields: ignore on read when possible; unsupported version → error
`ProviderCapabilities` `schema_version = 1`	stable-at-0.x	Preflight before expensive work
`PartialSession`, `PcmBuffer`, `ResourceGovernor`	stable-at-0.x	Host-facing concurrency / progressive STT
C ABI (`AURUM_ABI_VERSION = 2`)	provisional	Jobs include STT/cleanup/TTS; additive status codes preferred
Process-global whisper/TTS caches	legacy shared default	Isolated when using `AurumEngine`; residual only for non-engine paths
Internal `postprocess`, download, remote client details	internal	May change without notice
Experimental adapters / experimental STT models	feature-gated / experimental	Not part of the stability claim

SemVer (pre-1.0 / 0.0.x)¶

Aurum currently iterates as 0.0.x patch steps until a deliberate major step.

PATCH (0.0.x): bugfixes, docs, additive diagnostics, non-breaking DTO fields with defaults, evidence packs
Breaking 0.x: removed public items require a migration note and at least one release of deprecation when practical

Deprecation window¶

Prefer one release of #[deprecated] (or docs-only deprecation) before removal of public Rust APIs. C ABI breaks require AURUM_ABI_VERSION bump and header notes.

Unknown JSON fields¶

Readers of schema_version = 1 DTOs should ignore unknown fields. Writers must not emit NaN/Inf. Unsupported schema_version values fail clearly.

Compatibility fixtures¶

STT JSON: schema_version present; see unit tests in dto / output
Config: load_from / load_from_required / redacted diagnostic / ValidatedConfig
Engine: multi-engine metrics isolation tests
ABI: aurum-ffi abi_layout tests

Release checklist¶

Compatibility review of public surfaces
Update this document if classifications change
CHANGELOG migration note for any breaking 0.x change
Run cargo test + clippy + FFI abi tests