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 skills add hculap/better-code --skill tdd-methodologygit clone --depth 1 https://github.com/hculap/better-codeWrote 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/hculap/better-code/tdd-methodology)<a href="https://agentmods.dev/skills/hculap/better-code/tdd-methodology"><img src="https://agentmods.dev/badge/skills/hculap/better-code/tdd-methodology/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.
<a href="https://agentmods.dev/skills/hculap/better-code/tdd-methodology"><img src="https://agentmods.dev/badge/skills/hculap/better-code/tdd-methodology.svg" alt="Reviewed on agentmods" width="80" 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 5.1 | $0.00085 | $0.01603 |
| Opus 5.5 | $0.00034 | $0.00641 |
| Sonnet 5.5 | $0.00017 | $0.00321 |
| Haiku 4.5 | $0.00009 | $0.00160 |
Grade A, and why
TDD Methodology 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 2mo 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.
How it starts
The opening of the file, as written. The whole thing — 225 lines — stays where its author put it; the contents beside it link to each section on GitHub.
TDD Methodology
Transform coding behavior into strict Test-Driven Development practice. Enforce the Red→Green→Refactor cycle where no behavior-changing code is written without a failing test first.
Core Philosophy
TDD is not about testing—it is about design through tests. Tests drive the implementation, not the other way around.
The Iron Rules
- No production code without a failing test - Write a test that fails for the right reason before writing any implementation
- Minimal code to pass - Write only enough code to make the failing test pass, nothing more
- Refactor only when green - Clean up code only after all tests pass
- Small increments - Each cycle should be minutes, not hours
The Red→Green→Refactor Loop
┌─────────────────────────────────────────────────┐
│ │
│ RED: Write a failing test │
│ ↓ │
│ GREEN: Write minimal code to pass │
│ ↓ │
│ REFACTOR: Clean up while staying green │
│ ↓ │
│ (repeat) │
│ │
└─────────────────────────────────────────────────┘
Strictness Modes
Strict Mode (Default)
Block any behavior-changing implementation without a failing test:
- Refuse to write/edit source files until a failing test exists
- Enforce test-first for every behavior change
- No exceptions without explicit user override
Standard Mode
Warn and prompt for confirmation:
- Alert when attempting to write code without a failing test
- Ask: "No failing test exists. Proceed anyway? (yes/no)"
- Log violations for awareness
Relaxed Mode
Coach and suggest without blocking:
- Recommend writing tests first
- Provide guidance on TDD approach
- Allow user to proceed without tests
TDD Workflow Execution
What ships with it
4 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.
- 2mo ago First seen · 225 lines · 85 tokens per session scan A efe0fc692705
TDD Methodology is a skill published in the GitHub repository hculap/better-code (2 stars, last pushed 21d ago), licensed MIT. It adds 85 tokens to every session and 1,603 once invoked, about $0.0003 per session on Opus 5.5. 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
setup
Set up or update TDD Guard for the current project. Detects the test framework, installs or updates the matching reporter, and configures or migrates its configuration to match the current specification.
software-code-refactoring
Improve production code quality while preserving all existing test behavior. Commonly used for the Refactor phase of TDD red-green-refactor, but applicable to any codebase with tests. Use when production code works but needs cleanup — reducing duplication, improving naming, simplifying complexity, aligning with…
testing-principles
Language-agnostic testing principles for choosing which tests a change needs, test quality, and proof ownership, with frontend and browser E2E implementation references. Use when writing tests, deciding test scope, or reviewing test quality.
ring:running-dev-cycle
Running the backend dev cycle: implements every task in a rolling-wave plan.md (ring:writing-plans format) for a Go/TS service, driving specialist agents through Gate 0 implementation/TDD, Gate 8 parallel review, and Gate 9 validation per epic, elaborating later phases at each phase boundary. Use when starting or…
ring:instrumenting-streaming-events
Instrumenting streaming events: wires lib-streaming event emission end-to-end into a Lerian Go service via a 13-gate cycle (catalog, Builder bootstrap, Emit sites, outbox, HTTP manifest, NoopEmitter fallback, integration and chaos tests), dispatching ring:backend-go under TDD. Consumes the validated…
ring:implementing-tasks
Implementing a single planned task (Task N.M.T) end-to-end: selects the right backend agent by language and service type, drives one TDD RED->GREEN turn, then verifies coverage, lint, license headers, runtime, and delivery before handoff. Runs as Gate 0 before ring:reviewing-code. Use to drive ONE task inside an…