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testland/spec-testability-heuristics

Judges whether a written requirement can be tested at all, by scoring each claim against three heuristics: Observable (a state or output visible from outside the system), Decidable (a deterministic pass/fail against a named oracle), and Bounded (stated inputs, states, and users). Supplies untestable-to-testable rewrite pairs per heuristic, severity assignment, a BLOCK / REVIEW / OK verdict rule, and a findings table that pairs every flagged sentence with a concrete replacement. Scope is testability only: it does not write the tests, rank risk, or judge whether the requirement is correct or complete. Use when a user story, acceptance criterion, PRD section, API contract, or PR description is about to be handed to implementation and someone needs to know which sentences cannot be verified as written.

75

Quality

94%

Does it follow best practices?

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SecuritybySnyk

Low

Low-risk findings worth noting

Overview
Quality
Evals
Security
Files

Quality

Content

85%

Reviews the quality of instructions and guidance provided to agents. Good implementation is clear, handles edge cases, and produces reliable results.

A well-structured, highly actionable rubric body with concrete failure signatures, rewrite tables, a clear sequenced procedure, and a properly split-out worked-examples reference. Its only weakness is verbosity: several ISTQB glossary citations and basic testing-concept explanations restate knowledge Claude already has.

Suggestions

Trim or remove the inline ISTQB glossary definitions and citation URLs for testability, expected result, test oracle, equivalence partitioning, and boundary value analysis — Claude already knows these concepts, and the heuristics stand on their own without them.

Condense the 'What testability means here' opening, which quotes ISTQB at length before the practical content begins; a one-line framing would preserve the shift-left motivation with fewer tokens.

If retaining any external definitions, move them to references/ alongside the worked examples rather than quoting them inline in the main body.

DimensionReasoningScore

Conciseness

The core content (heuristic tables, severity, verdict rule, output template, anti-patterns) earns its place, but repeated ISTQB glossary citations and explanations of equivalence partitioning and boundary value analysis are concepts Claude already knows and could be trimmed, matching the score-2 'mostly efficient but includes some unnecessary explanation' anchor rather than the lean score-3.

2 / 3

Actionability

For an instruction-only skill it gives concrete, executable guidance: failure-signature word lists ('fast, clean, robust, seamless...'), untestable-to-testable rewrite tables per heuristic, a numbered 6-step procedure, and a copy-paste-ready output template with a filled example, matching the score-3 'specific examples; copy-paste ready' anchor.

3 / 3

Workflow Clarity

A clear 6-step sequence (split into claims -> test each against all three heuristics -> assign severity -> write a rewrite -> compute verdict -> emit findings table) with explicit severity and BLOCK/REVIEW/OK verdict rules gives an unambiguous process; this is a review skill, not a destructive/batch operation, so the missing-validation cap does not apply.

3 / 3

Progressive Disclosure

SKILL.md holds the overview (heuristics, procedure, output format) and splits the three end-to-end worked examples into a clearly signaled, one-level-deep reference to the verified references/worked-examples.md, matching the score-3 'clear overview with well-signaled one-level-deep references' anchor.

3 / 3

Total

11

/

12

Passed

Description

100%

Based on the skill's description, can an agent find and select it at the right time? Clear, specific descriptions lead to better discovery.

A specific, third-person description that names concrete capabilities (three heuristics, rewrite pairs, verdict rule, findings table), states a clear testability-only scope with explicit exclusions, and provides a concrete 'Use when' trigger clause listing the artifact types users would name. It fully satisfies the what/when/specificity/distinctiveness criteria.

DimensionReasoningScore

Specificity

Lists multiple concrete actions in third person — 'scoring each claim against three heuristics: Observable..., Decidable..., and Bounded...', 'Supplies untestable-to-testable rewrite pairs per heuristic, severity assignment, a BLOCK / REVIEW / OK verdict rule, and a findings table' — matching the score-3 anchor of several specific concrete actions rather than the partial coverage of score 2.

3 / 3

Completeness

It clearly states what it does (judges testability via the three heuristics and emits a findings table) and supplies an explicit 'Use when a user story, acceptance criterion, PRD section, API contract, or PR description is about to be handed to implementation...' trigger, matching the score-3 anchor for both 'what' and explicit 'when'; not score 2 because the when-clause is explicit, not implied.

3 / 3

Trigger Term Quality

Natural trigger coverage is strong: 'user story, acceptance criterion, PRD section, API contract, or PR description' are exactly the artifact names a user would say when they need a testability check, satisfying the score-3 'good coverage of natural terms' anchor rather than the partial keyword set of score 2.

3 / 3

Distinctiveness Conflict Risk

It carves a clear testability-only niche and explicitly excludes adjacent jobs ('it does not write the tests, rank risk, or judge whether the requirement is correct or complete'), so it is unlikely to trigger for the wrong skill, matching the score-3 'clear niche with distinct triggers' anchor.

3 / 3

Total

12

/

12

Passed

Validation

100%

Checks the skill against the spec for correct structure and formatting. All validation checks must pass before discovery and implementation can be scored.

Validation16 / 16 Passed

Validation for skill structure

No warnings or errors.

Reviewed

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