| name | drift-canary |
| description | Compatibility and schema drift canary — checks for database schema migration safety, breaking API contract changes, serializable payload mismatches, and backward compatibility drift. Triggers on keywords: "/drift-canary", "drift-canary", "contract drift", "breaking changes". Use when changing DB schemas, API contracts, serialized payloads, or required config keys. |
Drift Canary (Contract & Schema Drift Audit)
Audit code to ensure changes do not break backward compatibility or cause database/API mismatches.
Auditing Categories
- Breaking Schema Migrations — dropping columns, changing types, or adding non-null columns without defaults (crashes on deploy).
- API Contract breaking changes — modifying existing REST/GraphQL properties, removing endpoints, or adding required query fields that break old clients.
- Serialization mismatches — editing properties in serialized payloads (JSON, Protobuf, XML) without deserialization fallbacks.
- Library Contract Drift — changing a public method signature in a shared library without a deprecated wrapper.
- Environment Configuration drift — introducing new required config keys (
.env / OS vars) without defaults or fallback.
Expand/contract migration rules, per-format serialization fallbacks, and the breaking-vs-additive API checklist: read references/checks.md before scanning.
Scope: honor .coalmine.json schemaPaths / migrationDirs if set — scan those globs/dirs; else infer by inspecting the repo.
Discipline
- Style Drift Resolution (Fix mode): when an approved fix touches mixed-style code, conform the minority patterns to the dominant style (highest average usage) to minimize churn — never start a standalone style refactor.
Fix mode (choice-gated)
In Agent Context, after the report, present via ask_question:
- Apply safe deprecations: mark endpoints/methods deprecated + add backward-compatibility mapping wrappers. Each fix: checkpoint (git stash/commit in a git repo; else copy the file aside — never assume git) → apply → build + tests → auto-revert if newly red.
- Let me pick: user selects specific compatibility fixes.
- Report only: exit unchanged.
Output
| file:line | contract interface | severity | finding | migration path |
Severity: CRITICAL (breaking DB schema mutation / breaking API change) · HIGH (serialization type change) · MEDIUM (unmapped new required env key) · LOW (missing deprecation doc)
