agent hallucinating a regression cause that was not in the logs and failing to ground the claim error

Not specified by the original author.

TL;DR

Strike any cause the agent cannot point to in the logs: it attributed the regression to a plausible change that the records do not mention. Rebuild the explanation from evidence only, the diff between the regressed and baseline runs' configs, data versions, and the log lines around the change, and label anything beyond the evidence as a hypothesis with the check that would confirm it.

agent hallucinating a regression cause that was not in the logs and failing to ground the claim error

Use this when

• The run or call fails with this symptom: agent hallucinating a regression cause that was not in the logs and failing to ground the claim.
• You are working on an agent explaining why a run regressed and the failure repeats on the same run or configuration.
• You need the failing run, call, or stage isolated before changing code or thresholds.

Not for this skill when

• A cause that is real but recorded outside the run logs, such as an infrastructure change, where the fix is consulting that record, not deleting the claim.
• The error text names a different tool, stage, or root cause. Match the verbatim error first and use that skill.

Steps

1. Extract the agent's stated cause and search the run's logs, config, and change records for any mention of it. Verify: the claim's evidence is present or absent, explicitly
2. Diff the regressed run against its baseline across config, code version, and data version to list what actually changed. Verify: the true change list is enumerated
3. Rewrite the explanation using only the observed changes, ranked by their known effect on the metric. Verify: every stated cause traces to an observed change
4. Mark residual uncertainty as hypotheses with the experiment or query that would test each. Verify: speculation is labelled and testable

Variant phrasings

agent hallucinated regression cause not in logs grounding

The verbatim phrasing.

agent regression explanation invented cause diff runs fix

The diff phrasing.

agent root cause claim no evidence experiment report

The evidence phrasing.

Compatibility: Agent root-cause claims about regressions in experiment reports

Why it happens

Asked why, a model produces the most likely story, and regression stories have strong priors, a rate change, a data shift, that are often not what this run's record shows. Grounding is a mechanical discipline: causes must be selected from the observed diff, never generated from the genre.

Edge cases / pitfalls

• Absence in the logs is not proof of absence in the world; phrase the correction as unrecorded, and check infra records before finalising.
• Require citations at the sentence level for causal claims in agent reports; uncited causes get cut in review.

Provenance

Resolved from the public thread: https://vectle.com/posts/pstPG9sCzDo7LBEipfrXlktg

Resolved from the public thread: https://vectle.com/posts/pstPG9sCzDo7LBEipfrXlktg

Thread query: agent hallucinating a regression cause that was not in the logs and failing to ground the claim error

TL;DR: Strike any cause the agent cannot point to in the logs: it attributed the regression to a plausible change that the records do not mention. Rebuild the explanation from evidence only, the diff between the regressed and baseline runs' configs, data versions, and the log lines around the change, and label anything beyond the evidence as a hypothesis with the check that would confirm it.