Conciseness

The body is largely efficient — routing tables, defaults, executable functions, and checklists all earn their tokens — but contains minor over-explanation that could be trimmed: the motivational paragraph 'Liquidity matters because it determines the real cost of trading. The quoted price is not what you actually pay', the educational 'Illiquidity premium' note, and the host-specific '!' shell-probe preamble. It is not a 5 because a few passages explain concepts Claude already knows; it is not a 3 because padding is incidental, not pervasive.

Actionability

Sub-skills A, B, C, E, and F include complete, copy-paste-ready Python functions covering the common cases (dashboard, spread, volume, impact curve, turnover), and the two sections without inline code (B2, D1) point to verified sections in references/liquidity_reference.md containing the full templates. It is not a 4 because the guidance is fully executable end-to-end, with data access, computation, and presentation output all specified.

Workflow Clarity

The three-step sequence (dependency probe with DEPS_MISSING feedback loop, routing table with explicit request-to-sub-skill mapping, response checklist) is clear, with empty-data handling in code and mandatory caveats. It is not a 5 because some validation gaps remain — no guidance for retrying or degraded results when yfinance calls fail intermittently (a known flakiness), and no explicit checkpoint that fetched quote fields (bid/ask) were actually populated before interpreting spreads. It is not a 3 because checkpoints for the main failure modes (missing deps, empty history, invalid tickers) are present and explicit.

Progressive Disclosure

Structure is clean: a routing table and defaults up front, core sub-skills with inline code, and a single one-level-deep reference (references/liquidity_reference.md, 438 lines with its own table of contents) that genuinely contains the sections the body signals ('Options Spread Analysis' §341, 'Order Book Depth Proxy' §363), plus a closing 'Reference Files' section stating when to read it. It is not a 4 because navigation is easy and the split is appropriate with no orphaned or nested references.

Specificity

The description lists multiple concrete, specific capabilities — 'bid-ask spreads, volume and dollar volume (ADTV), top-of-book and options depth, square-root market impact and slippage estimates, turnover ratio, and Amihud illiquidity, rolled into a liquidity grade' — which comprehensively covers the skill's functionality with no generic filler. It is not a 4 because coverage extends across every sub-capability of the skill rather than leaving minor gaps.

Completeness

Both 'what' (first sentence enumerates the analysis capabilities and data source 'Yahoo Finance data (yfinance)') and 'when' ('Use this skill whenever the user asks about liquidity or trading costs — ...') are explicitly and concretely answered with trigger phrases. It is not a 4 because the 'when' clause is fully explicit with concrete trigger examples rather than merely serviceable.

Trigger Term Quality

Natural user phrasings are covered comprehensively: 'liquidity or trading costs', 'how easily a position can be entered or exited', 'what a large order would do to the price', 'spread or execution-cost estimates', 'order book depth, volume patterns, or liquidity comparisons', plus synonyms like 'small caps, penny stocks, and thinly traded names'. It is not a 4 because it goes beyond domain keywords to include full natural question forms users would actually say.

Distinctiveness Conflict Risk

It carves out a clear niche — stock liquidity/execution-cost analysis via yfinance — with triggers ('bid-ask spreads', 'market impact', 'thinly traded names') that would not fire for adjacent skills like general stock screening or options analysis. It is not a 4 because overlap risk is minimal, not just minor: every trigger term is liquidity-specific.