# PAT-0190 — Contract Drift

## Ontology Metadata

Code: PAT-0190
Version: PAT-0190@0.1.0
Ontology release: 0.1.0
Updated: 2026-05-10T00:00:00Z
Canonical 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.

## Primary Lenses

- 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-0170 — Convergence Lens
  - URL: /workbench/lenses/convergence-lens/
  - Summary: Compares parallel structural systems to determine whether they align under shared authority.

## Secondary Lenses

- LEN-0180 — Determinism Lens
  - URL: /workbench/lenses/determinism-lens/
  - Summary: Evaluates whether identical structural inputs produce equivalent structural outputs across repeated executions.

## Primary Issue Matches

- ISS-0040 — Actual Policy Differs From Declared Policy
  - URL: /workbench/issues/actual-policy-differs-from-declared-policy/
  - Summary: The policy the AI or workflow actually follows differs from the policy that is documented, declared, displayed, or expected.
- ISS-0031 — Context Changes After Restore
  - URL: /workbench/issues/context-changes-after-restore/
  - Summary: Restoring, reopening, resuming, or reloading a task changes the context that the AI uses to continue the work.
- ISS-0056 — Old Output Expectations Survive Migration
  - URL: /workbench/issues/old-output-expectations-survive-migration/
  - Summary: Expectations from a prior model, prompt, schema, tool, or workflow survive a migration and continue shaping review or downstream handling after they should be replaced.
- ISS-0042 — Policy Update Not Reflected in Output
  - URL: /workbench/issues/policy-update-not-reflected-in-output/
  - Summary: A policy, rule, standard, or instruction has been updated, but the AI output still follows the older version.
- ISS-0054 — Prompt Changed but Workflow Did Not
  - URL: /workbench/issues/prompt-changed-but-workflow-did-not/
  - Summary: A prompt changes but the workflow, parser, review step, routing rule, or downstream expectation still assumes the old prompt behavior.
- ISS-0055 — Rubric Changed but Results Did Not
  - URL: /workbench/issues/rubric-changed-but-results-did-not/
  - Summary: A review rubric, scoring rule, evaluation standard, or classification criterion changes, but AI results continue to reflect the old rubric.
- ISS-0057 — Same Contract Name Has Different Meanings
  - URL: /workbench/issues/same-contract-name-has-different-meanings/
  - Summary: The same prompt, schema, field, policy, tool, or workflow contract name is used in different places with different meanings.
- ISS-0034 — Stale Context Affects Output
  - URL: /workbench/issues/stale-context-affects-output/
  - Summary: Old context, prior instructions, outdated references, or earlier task state continue to affect output after they should no longer apply.
- ISS-0053 — Version Change Breaks Existing Prompt
  - URL: /workbench/issues/version-change-breaks-existing-prompt/
  - Summary: A prompt that previously produced usable results stops working after a version change in the model, tool, policy, schema, product surface, or workflow.

## Supporting Issue Matches

- ISS-0029 — AI Forgets Earlier Constraints
  - URL: /workbench/issues/ai-forgets-earlier-constraints/
  - Summary: A constraint, instruction, preference, or decision that should persist through the task stops affecting later output.
- ISS-0094 — Early Model Output Gets Overweighted Downstream
  - URL: /workbench/issues/early-model-output-gets-overweighted-downstream/
  - Summary: An early AI output receives too much authority in later workflow steps, decisions, reviews, or generated artifacts.
- ISS-0052 — Output Breaks After Model Change
  - URL: /workbench/issues/output-breaks-after-model-change/
  - Summary: Output that previously worked begins failing after a model, mode, runtime, or product behavior changes.
- ISS-0059 — Output Changed Without Declared Change
  - URL: /workbench/issues/output-changed-without-declared-change/
  - Summary: Output shape, content, format, fields, or behavior changes without a declared change to the prompt, schema, model, workflow, or governing rule.
- ISS-0058 — Prompt Behavior Changed Without Version Change
  - 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.
- ISS-0041 — Revoked Approval Still Treated as Active
  - URL: /workbench/issues/revoked-approval-still-treated-as-active/
  - Summary: An approval, permission, exception, or authorization that was revoked continues to affect AI behavior or workflow decisions as if it were still active.
- ISS-0067 — Same Rule Declared in Multiple Places
  - URL: /workbench/issues/same-rule-declared-in-multiple-places/
  - Summary: The same rule, constraint, instruction, or policy appears in multiple places, creating redundancy and possible drift.
- ISS-0004 — Saved Reference No Longer Works
  - URL: /workbench/issues/saved-reference-no-longer-works/
  - Summary: A saved source, citation, file reference, prompt reference, or workflow pointer previously worked but no longer resolves to the expected object or meaning.
- ISS-0106 — Small Change Produces Large Downstream Effects
  - URL: /workbench/issues/small-change-produces-large-downstream-effects/
  - Summary: A small prompt, schema, policy, output, or workflow change creates unexpectedly large effects in downstream steps.
- ISS-0019 — Tool Result Not Integrated Correctly
  - URL: /workbench/issues/tool-result-not-integrated-correctly/
  - Summary: The AI receives a tool result but misreads, ignores, overwrites, misplaces, or fails to incorporate it correctly into the final output or workflow state.