Validation Skill

Activate this skill when validating phase outputs during orchestration execution or when running standalone validation checks. This skill provides the pipeline, heuristics, and interpretation rules for verifying that changes meet quality standards.

Validation Pipeline

Execute validation steps in this order. Stop on the first blocking failure unless the user explicitly requests continuing.

Step 1: Build / Compile

Verify the project compiles without errors.

npx tsc --noEmit

cargo build

go build ./...

python -m py_compile [files]

mvn compile

./gradlew compileJava

Step 2: Lint / Format

Verify code meets style and quality standards.

npx eslint . && npx prettier --check .

cargo clippy && cargo fmt --check

go vet ./... && gofmt -l .

ruff check . && ruff format --check .

mvn checkstyle:check

./gradlew checkstyleMain

Step 3: Unit Tests

Run unit tests to verify behavior preservation.

npx jest

npx vitest run

cargo test

go test ./...

python -m pytest tests/

mvn test

./gradlew test

Step 4: Integration Tests

Run integration tests if available and applicable.

Detect integration test presence by looking for:

• tests/integration/

  ,

  test/integration/

  , or

  **/integration_test*

  directories/files
• Test files with

  integration

  in the name
• Test scripts in package.json (e.g.,

  test:integration

  )

Step 5: Manual Verification

For changes that cannot be automatically validated, present a checklist to the user.

Project Type Detection

Detect the project type by checking for the presence of these files in the project root:

package.json

typescript

Cargo.toml

go.mod

pyproject.toml

setup.py

pom.xml

build.gradle

build.gradle.kts

Gemfile

*.csproj

*.sln

When multiple indicators are present, validate each project type independently.

Validation Result Interpretation

Pass

All executed validation steps completed with exit code 0. No errors or warnings that indicate broken functionality.

Fail (Blocking)

Any of the following constitute a blocking failure:

• Build/compile errors
• Lint errors (not warnings, unless the project treats warnings as errors)
• Test failures
• Type errors

Warn (Non-Blocking)

The following are recorded but do not block progression:

• Lint warnings (when not configured as errors)
• Deprecation notices
• Coverage decreases (unless coverage threshold is configured)
• Format-only issues (can be auto-fixed)

Validation Modes

The validation strictness is controlled by

MAESTRO_VALIDATION_STRICTNESS

normal

strict

normal

lenient

Strictness Application

When evaluating each validation step:

1. Run the validation command and capture the exit code and output
2. Classify the result as Pass, Fail (Blocking), or Warn (Non-Blocking) using the standard criteria above
3. Apply the strictness mode:

   • strict

     : Fail (Blocking) AND Warn (Non-Blocking) both stop progression

   • normal

     : Only Fail (Blocking) stops progression

   • lenient

     : Record everything, stop nothing — append all results to session state and continue
4. If strictness causes a result to be downgraded from blocking to non-blocking, note this in the validation output: "Warning recorded but not blocking (lenient mode)"

Post-Phase Validation

When to Validate

Run validation after:

• Every phase that creates or modifies source code
• Every parallel batch completion (validate the combined result)
• Before marking any phase as

  completed

When to Skip Validation

Skip validation when:

• The phase only modified documentation files
• The phase only produced read-only analysis (

  architect

  ,

  code-reviewer

  reports)
• The user explicitly requests skipping validation

Record

skipped

Manual Verification Checklist

For changes that cannot be automatically validated, present this checklist template:

### Manual Verification Required

The following changes require manual verification:

- [ ] [Description of what to verify]
- [ ] [Visual/UI changes look correct]
- [ ] [Integration with external service works]
- [ ] [Environment-specific behavior confirmed]

Please confirm these items are verified before I mark this phase as complete.

Use manual verification for:

• UI/visual changes
• External service integrations
• Environment-specific configurations
• Performance improvements (require load testing)
• Security remediations (require penetration testing)

Incremental Validation Mode

When full pipeline validation is unnecessary, use targeted validation based on the type of changes in the completed phase:

Validation Scope by Change Type

• Phase created new files only (no existing files modified): Run lint + type check on the new files only. This provides fast feedback without running the full test suite against unchanged code.
• Phase modified existing files: Run the full test suite. Existing tests serve as behavior-preservation checks — any failure indicates a potential regression.
• Phase touched configuration files (build config, CI config, environment config, dependency manifests): Run the full pipeline (build + lint + type check + all tests). Configuration changes can have cascading effects across the entire project.
• Phase only produced documentation or analysis: Skip validation (record as

  skipped

  with rationale).

Scope Detection

Determine the change type automatically from the completing agent's Task Report:

1. Parse Files Created and Files Modified lists
2. Classify each file: source code, test code, configuration, documentation
3. Apply the most comprehensive validation scope that matches any changed file type (e.g., if one config file and three source files changed, run the full pipeline because config was touched)

Validation Failure Diagnosis

When validation fails, provide a structured diagnosis to help the orchestrator decide next steps.

Diagnosis Protocol

1. Categorize the failure: type error, lint error, test failure, build error, runtime error
2. Identify involved files: Which files from the current phase appear in the error output?
3. Determine causality: Is the failure caused by the current phase's changes, or is it a pre-existing issue?
   • Check: Does the failure reference files modified in this phase?
   • Check: Run validation against a clean snapshot while always restoring local state:

     • git stash push --include-untracked -m "maestro-causality-check"

     • [validation command]

       (capture exit code as

       validation_exit

       )

     • git stash pop

       (run regardless of

       validation_exit

       )
   • If

     validation_exit

     is non-zero in the clean snapshot, classify the failure as pre-existing.
   • If

     git stash pop

     fails, mark the diagnosis as inconclusive until restoration conflicts are resolved.
4. Classify resolution path:
   • Fixable by same agent: The error is in files the agent owns, the fix is straightforward (missing import, type mismatch, lint violation). Re-delegate to the same agent with the error context.
   • Requires different agent: The error is caused by an interface mismatch between phases. Identify which phase introduced the incompatibility.
   • Requires human input: The error reveals an ambiguity in the design or plan that cannot be resolved without user guidance. Escalate with full context.

Diagnosis Output Format

### Validation Diagnosis
- **Failure Type**: [type error | lint error | test failure | build error]
- **Failing Files**: [list of files from current phase involved in the failure]
- **Root Cause**: [brief description of why validation failed]
- **Pre-existing**: [yes | no — was this failure present before this phase's changes?]
- **Resolution Path**: [re-delegate to same agent | escalate to user | requires cross-phase fix]
- **Recommended Action**: [specific next step with context to include in re-delegation or escalation]