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Patch contract verify

Scope-Aware Patch Contract Verification

When a change intent is active, check_patch_contract(mode="verify") attributes regressions and gate changes to the declared scope rather than treating the entire workspace as one undifferentiated surface.

Regression attribution

Regressions from compare_runs are partitioned into two sets:

  • intent_regressions — findings whose file paths fall inside the declared allowed_files or allowed_related.
  • external_regressions — findings whose file paths are entirely outside the declared scope.

Only intent_regressions produce structural_regressions contract violations. External regressions are reported as informational context without failing the contract.

Findings with no extractable file paths are conservatively classified as intent-scope to avoid false-negative accepts.

Without an active intent, all regressions are treated as intent-scope and behavior is unchanged from the base contract.

Scope matching vs verify attribution

Scope check (unexpected_files) uses exact membership in allowed_files / allowed_related. Verify regression attribution uses fnmatchcase on those patterns (and treats path-less findings as in-scope). Do not assume identical matching rules across check and verify — declare literal paths in scope lists.

Gate-delta logic

Gate evaluation uses a two-layer attribution model:

  1. Gate delta — only gate changes between before-run and after-run are contract-relevant. A gate that was already failing before the edit is pre-existing, not a new violation. gate_worsened is true only when before_gate.would_fail is false and after_gate.would_fail is true.

  2. Gate attribution — when gate_worsened is true and an intent is active, the contract checks whether the gate-triggering signals come from intent scope: intent-scope regressions or intent-scope worsened metric symbols. If neither exists, the gate failure is external and does not produce a contract violation.

Status values

Status Meaning
accepted No intent-scope regressions, no gate worsening
accepted_with_external_changes Intent scope is clean but external signals exist
violated Intent-scope regressions, intent-caused gate failure, or scope violation
unverified Missing before or after run
expired Report digest mismatch since declaration

The accepted_with_external_changes status signals that another agent or concurrent edit introduced regressions outside the current intent scope. The verify response includes intent_regressions, external_regressions, intent_worsened, external_worsened, gate_worsened, and before_gate fields for full attribution visibility.

Decision table
Intent Intent regressions External regressions Gate worsened Intent caused gate Scope check Status
no any — any any — current logic unchanged
yes > 0 any any any any violated
yes 0 any yes yes clean violated
yes 0 any yes no clean accepted_with_external_changes
yes 0 > 0 no — clean accepted_with_external_changes
yes 0 0 no — clean accepted
yes 0 any any any violated violated (scope violation)

Baseline abuse

detect_baseline_abuse stays workspace-global. Baseline hygiene is a repository-level signal: if the baseline was updated while any regressions exist (even external), that is suspicious regardless of whose regressions they are.