What is feature-tdd-implementation?

A Test-Driven Development workflow, where you write a failing test, make it pass with the smallest change, and then improve the code. TDD is a way to build software by using tests to define behavior first.

Use it to choose the right RSpec test, verify that it fails, implement the behavior, and keep the tests passing during cleanup.

It makes the intended behavior explicit and helps catch regressions while the feature is being implemented.

feature-tdd-implementation — Command for Claude Code by ThibautBaissac

Install

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.

Clone the repo

git clone --depth 1 https://github.com/ThibautBaissac/rails_ai_agents

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.

README.md

[![agentmods](https://agentmods.dev/badge/commands/thibautbaissac/rails_ai_agents/feature-tdd-implementation/github.svg)](https://agentmods.dev/commands/thibautbaissac/rails_ai_agents/feature-tdd-implementation)

Your own site

<a href="https://agentmods.dev/commands/thibautbaissac/rails_ai_agents/feature-tdd-implementation"><img src="https://agentmods.dev/badge/commands/thibautbaissac/rails_ai_agents/feature-tdd-implementation/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.

Your own site · 80×15

<a href="https://agentmods.dev/commands/thibautbaissac/rails_ai_agents/feature-tdd-implementation"><img src="https://agentmods.dev/badge/commands/thibautbaissac/rails_ai_agents/feature-tdd-implementation.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 51 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.

When invoked 676 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.

Model	Per session	Once invoked
Fable 5.1	$0.00051	$0.00676
Opus 5.5	$0.00020	$0.00270
Sonnet 5.5	$0.00010	$0.00135
Haiku 4.5	$0.00005	$0.00068

Measured 2mo ago against content hash 33cb9ce440f8, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

feature-tdd-implementation 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.

.claude/commands/feature-tdd-implementation.md · 59 lines

How it starts

The opening of the file, as written. The whole thing — 59 lines — stays where its author put it; the contents beside it link to each section on GitHub.

TDD Cycle Skill

Overview

Guides the Red-Green-Refactor TDD cycle: write a failing test describing desired behavior, implement the minimum code to pass it, then improve the code while keeping tests green. See references/testing-patterns.md for code examples, common patterns, and anti-patterns.

Test Type Selection

Test Type	Use For	Location
Model spec	Validations, scopes, instance methods	`spec/models/`
Request spec	API endpoints, HTTP responses	`spec/requests/`
System spec	Full user flows with JavaScript	`spec/system/`
Service spec	Business logic, complex operations	`spec/services/`
Job spec	Background job behavior	`spec/jobs/`

Workflow Steps

Choose Test Type -- Pick the appropriate spec type from the table above based on what you are testing.
Write Failing Spec (RED) -- Write a spec that describes the desired behavior. Follow the structure template in the references file.
Verify Failure -- Run bundle exec rspec path/to/spec.rb --format documentation. The spec must fail with a clear message. If it passes immediately, either the behavior already exists or the spec is wrong.
Implement Minimal Code (GREEN) -- Write the minimum code to make the spec pass. No optimization, no extra edge-case handling, no refactoring yet.
Verify Pass -- Run the spec again. It must pass. If it fails, read the error, fix the implementation (not the spec unless it was wrong), and re-run.
Refactor -- Improve the code one change at a time: extract methods, improve naming, remove duplication, simplify logic. Run specs after each change. Undo if specs fail.
Final Verification -- Run all related specs. All must pass. If any fail, undo recent changes and try a different approach.

Good Spec Characteristics

One behavior per example: each it block tests one thing
Clear description: reads like a sentence with describe/context
Minimal setup: only create data needed for the specific test
Fast execution: prefer build over create, mock external services
Independent: tests do not depend on order or shared state

Read the full file on GitHub · 59 lines

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.

2mo ago First seen · 59 lines · 51 tokens per session scan A 33cb9ce440f8

Subscribe to this mod's changes

feature-tdd-implementation is a command published in the GitHub repository ThibautBaissac/rails_ai_agents (672 stars, last pushed 5mo ago), licensed MIT. It adds 51 tokens to every session and 676 once invoked, about $0.0002 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 2026-08-30.

TDD Testing

feature-tdd-implementation next to 6 commands from other repositories
Mod	Type	Stars	Last push	Licence	Scan	Tokens	Works with
feature-tdd-implementationThibautBaissac/rails_ai_agents	Command	672	5mo ago	MIT	A	51	Claude Code
bugfixnWave-ai/nWave	Command	631	yesterday	MIT	A	18	Claude Code
task-verifythixpin/pitway	Command	20	16d ago	MIT	A	0	Claude Code
usage-addthixpin/pitway	Command	20	16d ago	MIT	A	0	Claude Code
milestone-listthixpin/pitway	Command	20	16d ago	MIT	A	0	Claude Code
speckit.tdd.planarrrrny/zuraffa	Command	5	yesterday	MIT	A	37	Claude Code
tddcfrs2005/claude-init	Command	1.4k	7mo ago	MIT	A	37	Claude Code