Conciseness

The body is lean and assumes Claude's competence: no concepts are explained that Claude already knows, and every step carries instruction rather than padding. The only framing sentences ('Read the relevant development guidelines before starting your task' and the closing 'This step is mandatory before writing any code') are short and functional, so every token earns its place.

Actionability

Guidance is fully executable: exact commands ('python3 ./.trellis/scripts/get_context.py --mode packages', 'cat .trellis/spec/<package>/<layer>/index.md', 'cat .trellis/spec/guides/index.md'), exact artifact filenames (prd.md, design.md, implement.md), the specific section to follow ('Pre-Development Checklist'), and named example guideline files (error-handling.md, conventions.md, mock-strategies.md). Placeholders are appropriately templated, not pseudocode.

Workflow Clarity

The 8-step sequence is clear and correctly ordered, with conditional handling ('design.md if present') and an escalation checkpoint ('If the real scope turns out to be clearly larger than this, say so and why before continuing'). However, there are no explicit validation or feedback steps — e.g., what to do if get_context.py fails, .trellis/ is absent, or an index lacks a Pre-Development Checklist — which keeps it below the anchor requiring explicit validation loops. Since the skill is read-only preparation, not destructive or batch, the 3-cap does not apply.

Progressive Disclosure

The skill is under 50 lines with no external bundle files needed; the numbered-step organization is clear and self-contained. It also models one-level-deep disclosure well, explicitly steering past the index: 'The index is NOT the goal — it points you to the actual guideline files', which is exactly the navigation behavior the top anchor rewards.

Specificity

The description lists multiple concrete actions with a specific source directory: 'Discovers and injects project-specific coding guidelines from .trellis/spec/', 'Reads spec indexes, pre-development checklists, and shared thinking guides'. These are specific, verifiable capabilities rather than generic claims, comprehensively covering the skill's scope.

Completeness

It explicitly answers both questions: the 'what' ('Discovers and injects project-specific coding guidelines from .trellis/spec/... Reads spec indexes, pre-development checklists, and shared thinking guides') and the 'when' ('Use when starting a new coding task, before writing any code, switching to a different package, or needing to refresh project conventions and standards'). Both are concrete and explicit, matching the top anchor.

Trigger Term Quality

The 'Use when' clause covers natural phrases users would say: 'starting a new coding task', 'before writing any code', 'switching to a different package', 'refresh project conventions and standards'. Coverage is good but a few natural synonyms are missing (e.g., 'best practices', 'style guide', 'coding standards'), so it falls just short of the comprehensive anchor.

Distinctiveness Conflict Risk

The '.trellis/spec/' path carves out a clear niche, but the trigger conditions ('starting a new coding task', 'before writing any code') are broad enough to overlap with general conventions/documentation skills. It is mostly distinct with minor overlap risk against closely related skills.