# Prompt Behavior Changed Without Version Change

## Ontology Metadata

Code: ISS-0058
Version: ISS-0058@0.1.0
Ontology release: 0.1.0
Updated: 2026-05-10T00:00:00Z
Canonical URL: /workbench/issues/prompt-behavior-changed-without-version-change/

## Summary

A prompt begins producing different behavior even though no prompt version, model version, workflow version, or declared dependency change is recorded.

## Category

- CAT-0080 — Changes & Versions
  - URL: /workbench/categories/changes-and-versions/
  - Summary: Problems where model behavior, prompts, contracts, schemas, outputs, references, rubrics, or expectations change without the surrounding workflow updating correctly.

## Primary Pattern

- PAT-0380 — Silent Mutation
  - URL: /workbench/patterns/silent-mutation/
  - Summary: A structural condition where a change occurs without a corresponding declared update, authority update, or version change.

## Declared Patterns

- PAT-0380 — Silent Mutation
  - URL: /workbench/patterns/silent-mutation/
  - Summary: A structural condition where a change occurs without a corresponding declared update, authority update, or version change.
- PAT-0190 — Contract Drift
  - URL: /workbench/patterns/contract-drift/
  - Summary: A structural condition where a declared contract changes but connected structures, implementations, consumers, or expectations do not update in sync.
- PAT-0290 — Divergent Outputs
  - URL: /workbench/patterns/divergent-outputs/
  - Summary: A structural condition where parallel evaluations under comparable scope and shared authority produce non-equivalent outputs.

## Derived Primary Lenses

- LEN-0170 — Convergence Lens
  - URL: /workbench/lenses/convergence-lens/
  - Summary: Compares parallel structural systems to determine whether they align under shared authority.
- LEN-0180 — Determinism Lens
  - URL: /workbench/lenses/determinism-lens/
  - Summary: Evaluates whether identical structural inputs produce equivalent structural outputs across repeated executions.
- LEN-0270 — Reconciliation Lens
  - URL: /workbench/lenses/reconciliation-lens/
  - Summary: Evaluates whether structural changes align with declared authority updates, version changes, or reconciliation rules.
- LEN-0280 — Reference Stability Lens
  - URL: /workbench/lenses/reference-stability-lens/
  - Summary: Evaluates whether structural references, identifiers, nodes, and edges remain consistent across execution cycles or comparable states.
- LEN-0290 — Variance / Entropy Lens
  - URL: /workbench/lenses/variance-entropy-lens/
  - Summary: Measures structural variability across repeated or comparable evaluations and identifies divergence beyond expected bounds.

## Derived Secondary Lenses

- LEN-0140 — Compression Lens
  - URL: /workbench/lenses/compression-lens/
  - Summary: Reduces structural graphs into stable minimal representations for comparison, redundancy detection, and diffing.
- LEN-0260 — Provenance Trace Lens
  - URL: /workbench/lenses/provenance-trace-lens/
  - Summary: Attaches stable lineage to structural regions by mapping origin, reference history, and transformation path.

## Search Intents

- prompt behavior changed without version change
- prompt changed behavior but version same
- AI prompt started acting different
- same prompt different behavior no update
- prompt drift without version change
- AI behavior changed silently