dot-files: Skill for Claude Code

.claude/skills/tdd/SKILL.md

tdd is a skill for Claude Code from 2SSK/dot-files. It costs 0 tokens per session (421 once invoked), scanned A, original, MIT.

A Test-Driven Development workflow, or TDD, in which you write a failing test, add the smallest code that passes it, and then clean up the design. It gives examples for Go, TypeScript, and C++.

In plain words
What is it for?
Use it for implementation tasks when you want to define a unit's behaviour with a test, make it pass, and refactor without changing the result.
Why use it?
It makes the expected behaviour explicit before implementation and provides a check that the new code works. The small steps help avoid adding unneeded functionality.

Skill for Claude Code

Written for Claude Code: installed under .claude/. Also seen: mentions OpenCode.

This is 2SSK/dot-files's own configuration. It tells Claude Code how to work on dot-files itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything dot-files configures →

Reuse

Borrowing it

Nothing to install: this file belongs to 2SSK/dot-files. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file
curl -O https://raw.githubusercontent.com/2SSK/dot-files/main/.claude/skills/tdd/SKILL.md
Clone the repo
git clone --depth 1 https://github.com/2SSK/dot-files

Made for: Claude Code.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for tdd

README.md
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Your own site
<a href="https://agentmods.dev/skills/2ssk/dot-files/tdd"><img src="https://agentmods.dev/badge/skills/2ssk/dot-files/tdd/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for tdd

Your own site · 80×15
<a href="https://agentmods.dev/skills/2ssk/dot-files/tdd"><img src="https://agentmods.dev/badge/skills/2ssk/dot-files/tdd.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 0 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 421 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00000 $0.00421
Opus 5.5 $0.00000 $0.00168
Sonnet 5.5 $0.00000 $0.00084
Haiku 4.5 $0.00000 $0.00042

Measured 14d ago against content hash 9fc293feea31, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

tdd scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 14d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

.claude/skills/tdd/SKILL.md · 81 lines

What it actually says

Test-Driven Development Skill

Enforce TDD for every implementation task. This skill ensures quality throughtests first.

Workflow

Step 1 — Write Failing Test

  • Identify the smallest unit of behavior
  • Write test that fails because feature doesn't exist
  • Use language-specific testing framework
  • Keep test focused and simple

Step 2 — Write Minimal Code

  • Implement only what's needed to pass test
  • No optimization yet
  • No additional features
  • Get to green quickly

Step 3 — Refactor

  • Clean up code while tests pass
  • Improve structure, names, organization
  • Ensure tests still pass
  • No new functionality

Testing Patterns by Language

Go

func TestUnitName(t *testing.T) {
    t.Run("should do thing", func(t *testing.T) {
        // arrange
        input := ...
        expected := ...
        
        // act
        result := DoThing(input)
        
        // assert
        assert.Equal(t, expected, result)
    })
}

TypeScript

describe('UnitName', () => {
  it('should do thing', () => {
    const input = ...;
    const expected = ...;
    
    const result = doThing(input);
    
    expect(result).toEqual(expected);
  });
});

C++

TEST_F(UnitNameTest, ShouldDoThing) {
    auto input = ...;
    auto expected = ...;
    
    auto result = doThing(input);
    
    EXPECT_EQ(expected, result);
}

Quality Gates

  • All tests must pass before commit
  • Coverage ≥ 80% for new code
  • No flaky tests
  • Fast execution (< 30s for unit tests)
Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 14d ago First seen · 81 lines · 0 tokens per session scan A 9fc293feea31

Subscribe to this mod's changes

tdd is a skill published in the GitHub repository 2SSK/dot-files (250 stars, last pushed yesterday), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 421 tokens. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-10-02.