CtrlK
BlogDocsLog inGet started
Tessl Logo
SkillPublic

test-driven-development

Guides TDD (test-driven development) with red-green-refactor workflows, test-first feature delivery, bug reproduction through failing tests, behavior-focused assertions, and refactoring safety. Use when writing unit tests, implementing new functions, adding test coverage, fixing regressions, changing APIs, or restructuring code under test — especially when a user says "write tests first", "TDD", or "test before code".

Quality

94%

Does it follow best practices?

Run evals on this skill

Adds up to 20 points to the overall score

View guide
SecuritybySnyk

Passed

No findings from the security scan

SKILL.md
Quality
Evals
Security

Quality

Content

90%Weight 40%Scale 1-5

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

The body is a lean, highly actionable navigation hub: executable examples in two languages, concrete commands, and well-structured anti-patterns with rationale. Its main gaps are the absence of explicit error-recovery loops in the workflow and a reference index that surfaces only 6 of the 47 bundle files, leaving declared in-scope topics undiscoverable from the hub.

Suggestions

Add a reference-table entry (or index) for the in-scope but currently orphaned bundle files — e.g., link the isolate-* references under 'Mock/stub isolation strategy' and the org-* references under 'Naming and organization conventions', so all 47 files are reachable from SKILL.md.

Add explicit error-recovery steps to the Workflow section, e.g., 'If the test fails for an unexpected reason, fix the test or the diagnosis before writing implementation' and 'If refactoring breaks the suite, revert and re-run before proceeding', to close the feedback-loop gap.

DimensionReasoningScore

Conciseness

The body assumes Claude's competence: no explanation of what TDD or unit testing is, examples are minimal and self-contained ("test(\"add returns the sum of two numbers\", () => { expect(add(2, 3)).toBe(5); })"), and the anti-pattern entries pair a one-line WHY ("WHY: fixed waits create flaky and slow suites") with tight BAD/GOOD snippets. It matches anchor 5 ('lean and efficient; every token earns its place'); the only conceivable trim — merging the four small bash fences — is presentation, not padding, so it does not fall to anchor 4's 'minor instances of over-explanation'.

5 / 5

Actionability

Guidance is copy-paste ready throughout: complete TypeScript and Elixir red-green-refactor examples ("export function add(a: number, b: number): number { return a + b; }"), runnable commands ("bun test --watch", "mix test"), and concrete BAD/GOOD code for each anti-pattern ("await expect(promise).resolves.toBeDefined()"). This matches anchor 5 ('fully executable; copy-paste ready; specific examples cover the common cases') rather than anchor 4, which would require a missing detail in a common case.

5 / 5

Workflow Clarity

The Workflow section gives a clear five-step sequence with a RED-phase validation checkpoint ("Run tests and verify failure is for the expected reason") and the examples show expected failure output ("// ❌ Fails: cannot find module './add'"), placing it above anchor 3. It falls short of anchor 5's 'feedback loops for error recovery' because there is no explicit recovery guidance (e.g., what to do when the failing test fails for the wrong reason, or when the refactor breaks green beyond 'keeping the suite green').

4 / 5

Progressive Disclosure

The References section is well-signaled with a topic-labeled table of one-level-deep links, all of which resolve to real files (e.g., references/cycle-write-test-first.md, references/design-aaa-pattern.md), matching the good-structure anchor 4. It is not anchor 5 because the bundle contains 47 reference files while SKILL.md surfaces only 6: in-scope topics declared in the Scope section ("Mock/stub isolation strategy", "Naming and organization conventions") are covered by orphaned files (isolate-*, org-*) with no navigation path from the hub, which is more than a 'minor organization gap' at the bundle level yet short of anchor 3's 'references not clearly signaled'.

4 / 5

Total

18

/

20

Passed

Description

96%Weight 40%Scale 1-5

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

The description is strong: it states concrete capabilities in third person, provides an explicit 'Use when...' clause with natural quoted trigger phrases and synonyms, and clearly delimits the TDD niche. The only weakness is that a few 'Use when' conditions are broad enough to invite mild overlap with adjacent coding and testing skills.

DimensionReasoningScore

Specificity

Quotes five concrete, distinct actions: "red-green-refactor workflows", "test-first feature delivery", "bug reproduction through failing tests", "behavior-focused assertions", and "refactoring safety", which comprehensively cover the TDD domain. It matches the anchor-5 example (multiple specific concrete actions, comprehensive coverage) better than anchor 4, whose 'minor gaps' would require a noticeably missing capability — only 'refactoring safety' is slightly abstract, which is not enough to drop a level.

5 / 5

Completeness

The first sentence explicitly answers 'what' ("Guides TDD... with red-green-refactor workflows, test-first feature delivery, bug reproduction through failing tests, behavior-focused assertions, and refactoring safety") and the second explicitly answers 'when' with a concrete 'Use when...' clause plus quoted trigger phrases ("especially when a user says 'write tests first', 'TDD', or 'test before code'"). This is a direct match to the anchor-5 example, which pairs an explicit what with an explicit when including trigger phrases; no 'when' weakness exists that would justify a 4.

5 / 5

Trigger Term Quality

Natural trigger phrases are comprehensive and include synonym pairs and explicit user-quoted phrases: "writing unit tests", "adding test coverage", "fixing regressions", "TDD", "test-driven development", and especially "write tests first", "test before code". This matches the anchor-5 pattern (comprehensive natural terms including synonyms, like the 'PDF files, PDFs, .pdf' example); anchor 4 would require clearly missing common variations, and none of the obvious phrasings users would say are absent.

5 / 5

Distinctiveness Conflict Risk

The TDD niche is clear and the quoted trigger phrases ("write tests first", "TDD", "test before code") are distinct, but the broad 'Use when' items "implementing new functions", "adding test coverage", and "changing APIs" overlap with general coding/API-design and testing skills. This fits anchor 4 ('mostly distinct; minor overlap risk with closely related skills') better than anchor 5, whose 'minimal conflict risk' is undercut by those generic conditions.

4 / 5

Total

19

/

20

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.

Validation — 16 / 16 Passed

Validation for skill structure

No warnings or errors.

Repository

pantheon-org/tekhne

Path

skills/testing/test-driven-development/SKILL.md

Reviewed

Table of Contents

Is this your skill?

If you maintain this skill, you can claim it as your own. Once claimed, you can manage eval scenarios, bundle related skills, attach documentation or rules, and ensure cross-agent compatibility.