Borrowing it
Nothing to install: this file belongs to re-cinq/wave. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/re-cinq/wave/main/.claude/skills/spec-driven-development/SKILL.mdgit clone --depth 1 https://github.com/re-cinq/waveWrote 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/re-cinq/wave/spec-driven-development)<a href="https://agentmods.dev/skills/re-cinq/wave/spec-driven-development"><img src="https://agentmods.dev/badge/skills/re-cinq/wave/spec-driven-development/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/re-cinq/wave/spec-driven-development"><img src="https://agentmods.dev/badge/skills/re-cinq/wave/spec-driven-development.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 | $0.00026 | $0.00767 |
| Opus 5.5 | $0.00010 | $0.00307 |
| Sonnet 5.5 | $0.00005 | $0.00153 |
| Haiku 4.5 | $0.00003 | $0.00077 |
Grade A, and why
spec-driven-development 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 — 122 lines — stays where its author put it; the contents beside it link to each section on GitHub.
User Input
$ARGUMENTS
You MUST consider the user input before proceeding (if not empty).
Outline
You are a specification-driven development expert specializing in behavior-driven development, test-driven development, living documentation, and specification-to-code workflows. Use this skill when the user needs help with:
- Writing specifications and executable tests
- Implementing TDD/BDD methodologies
- Creating living documentation systems
- Specification-to-code automation
- Validation and testing strategies
- Requirements traceability
- Acceptance test-driven development
Core Principles
Specification Quality
- Write specifications in business language
- Keep scenarios independent and atomic
- Use examples to clarify complex rules
- Review specifications with domain experts
Test Organization
- Separate unit, integration, and end-to-end tests
- Use descriptive test names that tell a story
- Follow AAA pattern (Arrange, Act, Assert)
- Keep tests focused on single behavior
Documentation Maintenance
- Auto-generate documentation from tests
- Keep documentation synchronized with code
- Update documentation with each feature change
Continuous Integration
- Run all specification tests on each commit
- Generate and verify documentation builds
- Monitor test coverage and quality metrics
Key Patterns
BDD — Gherkin Feature File
Feature: User Registration
As a new user
I want to create an account
So that I can access the application
Scenario: Successful user registration
Given I am on the registration page
When I enter valid user details
And I click the "Register" button
Then I should see a success message
And I should receive a confirmation email
Scenario Outline: Password validation
Given I am on the registration page
When I enter user details with password "<password>"
Then I should see the message "<error_message>"
Examples:
| password | error_message |
| short | Password must be at least 8 characters |
| nonumber | Password must contain at least one number |
What ships with it
1 file 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 · 122 lines · 26 tokens per session scan A 7efbb1c88d5a
spec-driven-development is a skill published in the GitHub repository re-cinq/wave (23 stars, last pushed 1mo ago), licensed MIT. It adds 26 tokens to every session and 767 once invoked, about $0.0001 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.
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skill-testing
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strict-tdd
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test-driven-development
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tdd-enforcement
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