# PAT-0160 — Schema Breakage

## Ontology Metadata

Code: PAT-0160
Version: PAT-0160@0.1.0
Ontology release: 0.1.0
Updated: 2026-05-10T00:00:00Z
Canonical URL: /workbench/patterns/schema-breakage/

## Summary

A structural condition where an instance, graph, payload, or object violates the type, shape, or rule requirements of a declared schema.

## Primary Lenses

- LEN-0200 — Interface Contract Lens
  - URL: /workbench/lenses/interface-contract-lens/
  - Summary: Compares declared interface structure to observed runtime structure to detect contract deviations.
- LEN-0210 — Invariant Lens
  - URL: /workbench/lenses/invariant-lens/
  - Summary: Verifies that declared invariants are structurally enforceable and not contradicted by observed structure.

## Secondary Lenses

- LEN-0150 — Conflict Lens
  - URL: /workbench/lenses/conflict-lens/
  - Summary: Detects mutually incompatible constraints, claims, states, or declarations that cannot be simultaneously satisfied.

## Primary Issue Matches

- ISS-0026 — AI Output Breaks Parser
  - URL: /workbench/issues/ai-output-breaks-parser/
  - Summary: The AI output causes a parser, validator, importer, or structured-output consumer to fail.
- ISS-0021 — Invalid JSON Output
  - URL: /workbench/issues/invalid-json-output/
  - Summary: The AI returns malformed JSON or structured output that cannot be parsed.
- ISS-0025 — Nested Fields Do Not Match
  - URL: /workbench/issues/nested-fields-do-not-match/
  - Summary: The AI returns nested structured fields whose internal shape, hierarchy, parent-child relationship, or contained values do not match the expected structure.
- ISS-0024 — Wrong Field Types
  - URL: /workbench/issues/wrong-field-types/
  - Summary: The AI returns fields with values whose types do not match the expected schema, such as strings where numbers, booleans, arrays, objects, or enums are required.

## Supporting Issue Matches

- ISS-0097 — Downstream Steps Magnify Hallucinated Claim
  - URL: /workbench/issues/downstream-steps-magnify-hallucinated-claim/
  - Summary: A hallucinated or unsupported claim from an AI output is reused by later workflow steps until it becomes more influential than the evidence supports.
- ISS-0027 — Duplicate Fields With Same Meaning
  - URL: /workbench/issues/duplicate-fields-with-same-meaning/
  - Summary: The AI returns multiple fields, labels, sections, or structured elements that carry the same meaning and create ambiguity about which one should be used.
- ISS-0066 — Duplicate Output Sections
  - URL: /workbench/issues/duplicate-output-sections/
  - Summary: The AI repeats sections, headings, blocks, or output areas in a way that creates redundancy, confusion, or downstream handling problems.
- ISS-0028 — Format Rule Too Weak
  - URL: /workbench/issues/format-rule-too-weak/
  - Summary: The format instruction is too vague, incomplete, or optional to reliably produce output that satisfies the expected structure.
- ISS-0023 — Hallucinated Fields
  - URL: /workbench/issues/hallucinated-fields/
  - Summary: The AI adds fields, keys, attributes, columns, or structured elements that were not declared, requested, or allowed by the expected schema.
- ISS-0022 — Missing Required Fields
  - URL: /workbench/issues/missing-required-fields/
  - Summary: The AI returns structured output that omits fields required by the schema, workflow, parser, form, or downstream consumer.
- ISS-0018 — Output Breaks the Next Step
  - URL: /workbench/issues/output-breaks-the-next-step/
  - Summary: The AI output looks acceptable by itself but cannot be used by the next tool, workflow step, parser, reviewer, or downstream consumer.
- ISS-0091 — Schema Reference Loops Without Base Case
  - URL: /workbench/issues/schema-reference-loops-without-base-case/
  - Summary: A schema, field, type, object, or structured reference points through a loop without a base case that allows validation or interpretation to resolve.
- ISS-0107 — Single Field Carries Too Many Obligations
  - URL: /workbench/issues/single-field-carries-too-many-obligations/
  - Summary: One field, label, score, status, or structured value is expected to carry too many meanings, decisions, or workflow obligations.
- ISS-0017 — Tool Call Contract Mismatch
  - URL: /workbench/issues/tool-call-contract-mismatch/
  - Summary: The AI or agent calls a tool with names, arguments, types, modes, or shapes that do not match the declared tool interface.
- ISS-0006 — Validation Result Changes on Retry
  - URL: /workbench/issues/validation-result-changes-on-retry/
  - Summary: A validation, grading, review, classification, or pass/fail result changes after retry even though the input and declared validation rules did not change.