Coverage Ratcheting Skill

Enforce a coverage ratchet: coverage for each package must never decrease from its high-water mark.

Trigger Conditions

• Test suite run completes with coverage data
• PR is submitted for review
• Coverage thresholds are checked in CI
• User invokes with "coverage check" or "coverage-ratcheting"

Input Contract

• Required: Current coverage data (from

  go test -cover

  )
• Optional: Previous coverage baseline for comparison

Output Contract

• Per-package coverage percentages
• Coverage delta from baseline (improved / unchanged / regressed)
• Packages below minimum threshold per rule 123
• Ratchet violations (packages that decreased from high-water mark)
• Recommended test additions to close gaps

Tool Permissions

• Read: Test files, coverage reports, source files
• Write: Coverage baseline file (if updating)
• Shell: Run

  go test -coverprofile

• Search: Grep for untested functions

Execution Steps

1. Run tests with coverage: Execute

   go test -coverprofile=coverage.out ./...

2. Parse coverage: Extract per-package and per-function coverage
3. Compare to baseline: Check each package against its previous high-water mark
4. Check thresholds: Verify each package meets minimum thresholds per rule 123
5. Identify regressions: Flag any package where coverage decreased
6. Recommend: For packages below threshold, identify the uncovered functions
7. Update baseline: If coverage improved, update the high-water mark

Minimum Thresholds (from rule 123)

• internal/service/

  — 90%

• internal/repository/

  — 85%

• internal/handler/

  — 80%

• internal/middleware/

  — 80%

• internal/models/

  — 75%

References

• .cursor/rules/123-test-requirement-matrix.mdc