Use when you need to identify likely regression surfaces, impacted tests, risk boundaries, and verification focus.
How this skill is triggered — by the user, by Claude, or both
Slash command
/skillry-testing-and-qa:54-regression-scope-analysisThe summary Claude sees in its skill listing — used to decide when to auto-load this skill
Given a set of code changes (PR diff, commit range, or file list), determine the blast radius: which application areas are affected, which existing tests cover those areas, which areas have no test coverage, and what the minimum required verification suite is before the change is considered safe. Produce a prioritized test execution plan, not just a list of changed files.
Given a set of code changes (PR diff, commit range, or file list), determine the blast radius: which application areas are affected, which existing tests cover those areas, which areas have no test coverage, and what the minimum required verification suite is before the change is considered safe. Produce a prioritized test execution plan, not just a list of changed files.
Get the diff. Run git diff main...HEAD --name-only (or the relevant base branch) to get the list of changed files. For a specific commit range: git diff <base-sha>..<head-sha> --name-only.
Categorize changed files by layer. Group files into:
Identify fan-out for infrastructure changes. For every shared module that changed, trace its import graph: which feature modules import it? Use grep -r "from.*<module>" src/ or equivalent. A change to src/db/query-builder.ts that is imported by 40 files has a very different blast radius than one imported by 2.
Map changed code to existing tests. For each changed non-test file, find the corresponding test file(s). Check:
*.test.ts, *.spec.ts)?Identify coverage gaps. For each changed file with no corresponding test, flag it explicitly. A coverage gap in a changed file is high risk.
Assess data migration risk. If schema files, migration files, or ORM model files changed, flag that data migration must be tested against a copy of production-representative data, not just a seed.
Determine minimum verification suite. Based on the above, produce a tiered list:
Estimate re-test time. For each tier, approximate how long the tests take based on existing CI run times if available.
Flag cross-cutting concerns. Changes to auth middleware, logging, error handling, or observability affect every request path — treat these as maximum blast radius even if the import graph appears limited.
## Regression Scope Analysis
### Changed files by layer
- Infrastructure (high fan-out): list
- Domain/business logic: list
- API/transport: list
- UI/presentation: list
- Test files only: list
### Blast radius assessment
- Modules importing changed infrastructure files: N files, key areas: X, Y, Z.
- Schema/migration changes: yes/no — data integrity test required.
- Cross-cutting concerns modified: yes/no — details.
### Test coverage mapping
| Changed file | Test file(s) | Coverage status |
|--------------|-------------|-----------------|
| src/foo.ts | src/foo.test.ts | Covered |
| src/bar.ts | none | GAP — high risk |
### Minimum verification suite
**Mandatory (run before merge):**
- npx jest src/foo.test.ts src/baz.integration.test.ts
- estimated time: ~Xmin
**Recommended (run if CI time allows):**
- npx jest --testPathPattern="auth|user|billing"
- estimated time: ~Xmin
### Risk summary
- Highest risk change: [file] because [reason].
- Uncovered changed files: N — recommend adding tests before merge.
git diff, git log, git grep) and file searches.Provides a checklist for code reviews covering functionality, security, performance, maintainability, tests, and quality. Use for pull requests, audits, team standards, and developer training.
npx claudepluginhub fluxonlab/skillry --plugin skillry-testing-and-qa