JournalDAY 40 / X

FIELD NOTE / X

Policy-change drills belong in agent QA.

The complete written thought and the evidence behind it. The video edition will follow its public release.

Journal September 25, 2026 · X target November 6, 2026

Policy-change drills belong in agent QA.

Video caption

Policy-change drills belong in agent QA. Structural validation does not prove business disposition. Require a passing continuity contract before release. #EricFieldNotes

Full written post / accessibility read

Your code can stay fixed while a model route refuses, loses access or returns an unfamiliar error. If QA only tests happy prompts, the first real route change tests your business process in production.

A structured output can be perfectly valid while a refused case is mapped to the default category. Token masking can enforce the shape of an answer; it cannot certify that the case should close. A downstream state readback is still necessary.

In a disposable queue, simulate an explicit refusal, a network cut after dispatch, an unrecognized provider code and a delayed result after the case changed. Verify owner, retry bound, no silent close and no action on stale data. Keep one expected-state oracle outside the worker.

Version the route configuration and run fault drills when it changes. Do this because a provider-policy boundary can change what your application receives, while your application still owns its downstream effects.

#EricFieldNotes

Four-beat scene transcript

1. Policy-change drills belong in agent QA.

Your code can stay fixed while a model route refuses, loses access or returns an unfamiliar error. If QA only tests happy prompts, the first real route change tests your business process in production.

Visual: A route can change without a code commit.

2. A schema can hide a wrong default.

A structured output can be perfectly valid while a refused case is mapped to the default category. Token masking can enforce the shape of an answer; it cannot certify that the case should close. A downstream state readback is still necessary.

Visual: Structural validation does not prove business disposition.

3. Inject four route faults.

In a disposable queue, simulate an explicit refusal, a network cut after dispatch, an unrecognized provider code and a delayed result after the case changed. Verify owner, retry bound, no silent close and no action on stale data. Keep one expected-state oracle outside the worker.

Visual: Refusal, timeout, unknown code and stale result.

4. Treat external rule changes like code changes.

Version the route configuration and run fault drills when it changes. Do this because a provider-policy boundary can change what your application receives, while your application still owns its downstream effects.

Visual: Require a passing continuity contract before release.

Research and claim limits

The examples identified as illustrative or simulated are design probes, not reported incidents. Vendor specifications do not establish workload performance.

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