Conciseness

The body is short and free of concept explanations Claude already knows, but it could be tightened: 'never use untyped FormGroup' and 'extract into standalone validator functions' are each stated twice (rules sections plus Anti-Patterns), the same reference link is repeated three times, and lines like 'This ensures form values always strings — avoids null in form values' and the cryptic 'Canonical response anchors' section add noise. This matches the 'mostly efficient but could be tightened' anchor rather than the minor-trim anchor at 4.

Actionability

Bullets name concrete APIs ('fb.nonNullable.group(...)', 'takeUntilDestroyed()', 'validators.ts') but the body contains no executable code — all examples are deferred to references/typed-forms.md — and section 2 mixes an unrelated directive ('Sync valueChanges to stores') into the validation-extraction rule. This is 'some concrete guidance but incomplete' rather than the mostly-executable 4 anchor.

Workflow Clarity

This is a conventions skill with three clearly stated, unambiguous rules rather than a multi-step workflow, and no destructive or batch operations require validation checkpoints. It sits at 4 rather than 5 because section 2's directive is convoluted ('Name the validator module as a separate file... in the response') and bundles an off-topic valueChanges/store-sync bullet that muddies the rule's intent.

Progressive Disclosure

The body is under 50 lines, well-sectioned, and points to a real one-level-deep reference (references/typed-forms.md, verified to exist with executable examples) that is clearly signaled both inline and in a References section. It misses 5 because the trailing 'Canonical response anchors: Additional task-grounded exact anchors: separate file' section is a dangling pointer that names no actual file and adds navigation confusion.

Specificity

The description lists several concrete actions — 'Build typed reactive forms with strict FormGroup typing, custom validators, and nonNullable controls in Angular' — naming specific APIs and techniques. It falls short of a 5 because 'typed reactive forms' and 'strict FormGroup typing' largely restate the same action, so effective coverage is narrower than the raw action count suggests.

Completeness

It explicitly answers 'what' ('Build typed reactive forms with strict FormGroup typing, custom validators, and nonNullable controls') and 'when' with a concrete 'Use when...' clause listing three trigger phrases. This matches the anchor for clearly answering both with concrete triggers; below it, the 'when' would be weaker or implied.

Trigger Term Quality

'implementing typed reactive forms, custom validators, or form control patterns' gives good natural keyword coverage that an Angular developer would actually say. A few natural variations are missing (e.g., 'form validation', 'Angular forms', file/type references), so it does not reach the comprehensive synonym coverage of a 5.

Distinctiveness Conflict Risk

'typed reactive forms... in Angular' with 'FormGroup'/'nonNullable' triggers carves out a clear niche with minimal overlap against generic forms or validation skills. It is not the 4-anchor case because the trigger phrases are Angular-forms-specific rather than shared with closely related skills.