Shadow mode: observe without blocking

Execution contract

The existing tool call, crawl or ingestion operation remains authoritative during shadow mode. Evidence resolution runs beside it and writes a separate audit event. Evidence failure must not change the existing result in Observe mode.

Use the hosting platform background primitive when available, such as waitUntil, a queue or a durable job. Do not rely on an unobserved promise if the process may terminate immediately.

const result = await existingToolCall();
background(resolveEvidence().then(audit.write));
return result; // no enforcement in Observe mode

Four adoption modes

OBSERVE: log evidence only. ATTACH: add evidence to the returned result or document metadata. ADVISE: pass evidence into the existing policy engine. ENFORCE: the partner policy engine may block or route based on its own rule.

AcqPath provides the evidence contract in every mode. It does not become the partner policy engine.

Failure semantics

resolved means verified evidence is available. unavailable means the provider or source could not produce a usable result. unsupported means the requested purpose or source is outside the supported contract. invalid means evidence failed validation.

A semantic unknown is still resolved evidence with statement unknown. Do not collapse unknown and unavailable into the same state.