Evidence Layers

OAT dispatch evidence is layered so that trust flows from what OAT can prove toward what it can only observe. The launcher always knows which policy it resolved and which exact route it configured and launched, so that evidence is authoritative. A child's self-report of its own model is corroboration, not ground truth — it may be missing, delayed, or untrusted without ever invalidating the configured-invocation record.

The model has three layers. The first two are what OAT decided and did; the third is what a runtime happened to say about itself. Assertions target the first two layers. The third is recorded as reported or not-reported and never gates a conclusion on its own.

Layer map

Assertions bind to Layers 1 and 2. Layer 3 is recorded as reported or not-reported; its absence never invalidates Layer 2.

Layer 1 — Policy resolution

Layer 1 is the output of the dispatch-ceiling / policy resolver: the named ceiling in effect, the eligible candidates under that ceiling, and whether the policy is capped (a named maximum such as balanced or high), uncapped (explicit managed state), or inherit/default. It answers what was allowed before any single task chose a target.

This layer is a maximum and a candidate set, not a selection. A named high ceiling keeps lower configured tiers eligible; it does not pin one family or effort. See Dispatch Policy for named policy choices, candidate ladders, and the resolver contract.

Layer 2 — Launcher-owned configured invocation

Layer 2 is the dispatch record the launcher writes when it selects and launches a route. It is the authoritative evidence of what was configured and launched, and it records:

the selected route and the exact target, model axis, and effort axis;
the selection.reason, drawn from the stable shared values native-catalog, native-catalog-unsatisfying, pre-start-rejection, inherit, and gate-target (adapters may add a more specific diagnostic but never replace or rename these);
the ordered candidates_considered before launch (never sorted);
launch acceptance status (accepted or pre-start-rejected) and mechanism.

Because the launcher constructs the invocation payload itself, this layer does not depend on any child cooperation. A launch is judged consistent only when its candidate tier, selected model/effort axes, ceiling model/effort axes, policy, and exact target all agree. The atOrBelowCeiling boolean the launcher provides is retained as source evidence but is not trusted by assertions — they recompute eligibility from the configured candidates and named ceiling instead. This layer maps to Dispatch Report V1 and its provenance record; see the Dispatch Report V1 / producer provenance section.

Layer 3 — Runtime-observed identity (optional corroboration)

Layer 3 is the only layer that reflects what a runtime said about itself, and it is optional corroboration. It is normalized to reported only when both the producer and model are present and provenance is one of runtime-observed, provider-output, or gate-corroborated. Anything else — missing producer, missing model, or a non-trusted provenance value — normalizes to not-reported.

Requested controls, configured defaults, role-name parsing, and reviewer self-identification do not become observed runtime identity. Crucially, a missing or not-reported runtime identity never invalidates the launcher-owned configured-invocation evidence in Layer 2. Selected model and effort axes stay exact even when runtime producer identity is not reported.

How the smoke runner consumes these layers

The smoke runner's evidence pipeline reads all three layers and asserts only on the trustworthy ones. Launcher-owned records (dispatch/<scope>-<attempt>.json), orchestration state-transition records, and gate JSON are written before collection. The collector then flows the evidence through three stages:

Bundle — collect the immutable dispatch, orchestration, and gate records into a normalized evidence bundle, preserving structured candidates and recomputing eligible candidates through the named ceiling. Runtime identity is normalized here to reported / not-reported.
Assertion profiles — apply the profiles that assert on Layers 1 and 2 (policy resolution and configured invocation), while recording Layer 3 as corroboration only.
Report — emit the evidence report from launcher-owned records and gate artifacts, carrying reported / not-reported runtime status without letting a missing Layer 3 fail a Layer 2 assertion.

For how to run this end to end and when to refresh the fixture, see Smoke testing.

Dispatch Policy — Dispatch Report V1 and the producer-provenance record that back Layers 1 and 2.
Orchestration Model — the dispatch topology that produces these records.
Review Flavors — how the four review flavors are recorded through the same launcher-owned evidence.
Smoke testing — operating the evidence pipeline against real providers.