Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx agentmods add skills/sakhilchawla/skillkit/tddnpx skills add sakhilchawla/skillkit --skill tddgit clone --depth 1 https://github.com/sakhilchawla/skillkitWrote 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.
[](https://agentmods.dev/skills/sakhilchawla/skillkit/tdd)<a href="https://agentmods.dev/skills/sakhilchawla/skillkit/tdd"><img src="https://agentmods.dev/badge/skills/sakhilchawla/skillkit/tdd.svg" alt="Measured on agentmods" height="20"></a>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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5 | $0.00017 | $0.00393 |
| Opus 5 | $0.00009 | $0.00197 |
| Sonnet 5 | $0.00003 | $0.00079 |
| Haiku 4.5 | $0.00002 | $0.00039 |
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 4d 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.
What it actually says
Test-Driven Development
Implement $ARGUMENTS using strict RED-GREEN-REFACTOR discipline.
Phase 1: RED — Write a failing test
- Understand the requirement from $ARGUMENTS
- Write ONE test that describes the desired behavior
- Run the test — it MUST fail
- Verify it fails for the RIGHT reason (not syntax/import errors)
- If it fails for the wrong reason, fix the test setup first
- Do NOT write any production code yet
Phase 2: GREEN — Make it pass
- Write the MINIMUM code to make the failing test pass
- Do not add features beyond what the test requires
- Run ALL tests (not just the new one) — they must ALL pass
- If existing tests break, fix them before continuing
Phase 3: REFACTOR — Clean up
- Look for duplication, unclear names, overly complex logic
- Refactor while keeping ALL tests green
- Run tests after each refactoring step
- If any test breaks during refactor, undo the last change
Cycle
Repeat Phase 1-3 for each behavior. One test at a time. Never write production code without a failing test.
Rules
- Never skip RED. Every behavior needs a failing test first.
- Never write more code than the test demands in GREEN.
- Never break existing tests.
- Remove all debug artifacts (console.log, .only, .skip) before completing.
- Detect the test framework from project config (jest, vitest, pytest, go test, cargo test, etc.)
What ships with it
2 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
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.
- 4d ago First seen · 47 lines · 17 tokens per session scan A c72496683007
tdd is a skill published in the GitHub repository sakhilchawla/skillkit (6 stars, last pushed 5mo ago), licensed MIT. It adds 17 tokens to every session and 393 once invoked, about $0.0001 per session on Opus 5. 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 2026-08-31.
Other skills, from other repositories
tdd
Test-driven development. Use when the user wants to build features or fix bugs test-first, mentions "red-green-refactor", or wants integration tests.
agentic-testing
MANDATORY before creating, editing, or reviewing tests in agentic.nvim, and before behavior changes that require TDD. Covers mini.test workflow, red/green rules, commands, mark-count checks, and which test references to load.
test-first-bugs
Enforces a test-driven bug-fixing workflow. Use when a user reports a bug, failing code, an error, or asks to fix something.
tdd
Test-driven development (TDD) process used when writing code. Use whenever you are adding any new code, unless the user explicitly asks to skip TDD or the code is exploratory/spike.
growing-outside-in-systems
Drive feature development using Outside-In TDD with Hexagonal Architecture. Design emerges through inline code, in-memory fakes, interface extraction, and deferred I/O. Use when building features, writing tests, or structuring backend services. Triggers on: TDD, outside-in, hexagonal, ports and adapters, emergent…
plan-create
Create structured implementation plans for autonomous TDD development. Use for new features, multi-file changes, or anything requiring multiple steps or tests. Triggers on aspirational openers ("let's build", "let's start building", "I want to make", "I want an app that", "help me build"), capability lists ("users…