A specification-first development workflow that writes a SPEC.md file, has a four-person council review it, and turns its acceptance criteria into failing tests before implementation. Acceptance criteria are the concrete conditions a feature must meet.

Use it with a Linear ticket or a feature description to document the problem, goal, API contract, acceptance criteria, and edge cases. It then creates language-specific failing tests from those criteria.

It exposes unclear goals, missing edge cases, inconsistent interfaces, and security concerns before code is written. Tests created from the specification make the intended behavior checkable during implementation.

How stoa-platform/stoa configures Claude Code

Reuse

Borrowing it

Nothing to install: this file belongs to stoa-platform/stoa. 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/stoa-platform/stoa/main/.claude/skills/spec-driven/SKILL.md

Clone the repo

git clone --depth 1 https://github.com/stoa-platform/stoa

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/skills/stoa-platform/stoa/spec-driven/github.svg)](https://agentmods.dev/skills/stoa-platform/stoa/spec-driven)

Your own site

<a href="https://agentmods.dev/skills/stoa-platform/stoa/spec-driven"><img src="https://agentmods.dev/badge/skills/stoa-platform/stoa/spec-driven/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/skills/stoa-platform/stoa/spec-driven"><img src="https://agentmods.dev/badge/skills/stoa-platform/stoa/spec-driven.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 25 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 571 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	$0.00025	$0.00571
Opus 5.5	$0.00010	$0.00228
Sonnet 5.5	$0.00005	$0.00114
Haiku 4.5	$0.00003	$0.00057

Measured 2mo ago against content hash 9372f6d19111, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

spec-driven 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/skills/spec-driven/SKILL.md · 65 lines

How it starts

The opening of the file, as written. The whole thing — 65 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Spec-Driven Development

CAB-2005: Formalize the spec-first pattern. Council validates the spec BEFORE code. Acceptance criteria become test cases. Tests are written BEFORE implementation.

Usage

/spec-driven CAB-XXXX
/spec-driven "feature description"

Step 1: Create Spec

If a CAB-XXXX ID is given, fetch the ticket from Linear: linear.get_issue("CAB-XXXX")
Copy template from .claude/templates/SPEC.md
Fill in: Problem, Goal, API Contract, Acceptance Criteria, Edge Cases
Write to branch root as SPEC.md

Step 2: Council on Spec (Stage 1 variant)

Run the 4-persona Council but evaluate the spec quality, not the feature itself:

Chucky: Are edge cases covered? Missing failure modes?
OSS Killer: Is the goal measurable? Will this deliver user value?
Archi: Is the API contract consistent with existing patterns? Breaking changes?
Better Call Saul: Security considerations complete? PII/GDPR noted?

Threshold: >= 7.0 to proceed. Below 7.0: revise spec first.

Step 3: Generate Failing Tests

From each acceptance criterion, generate a test:

Python (api): test_spec_ac1_<description>() in tests/test_spec_<ticket>.py
TypeScript (ui/portal): describe('spec/CAB-XXXX', () => { it('AC1: ...') }) in src/__tests__/spec/
Rust (gateway): fn spec_ac1_description() in inline #[cfg(test)] mod tests

All tests MUST fail (red) at this stage. If any passes, the criterion is already met or the test is wrong.

Step 4: Implement

Write code to make all tests pass. Standard Pattern 3 workflow.

Step 5: Verify

All spec tests green
No other tests broken
SPEC.md stays in the branch (committed with the PR) as documentation

Rules

Spec lives in branch root, committed in the same PR as the implementation
Council scores the spec, not the implementation plan
Every acceptance criterion = exactly one test
Edge cases table = additional tests (tagged @edge-case)
If spec changes during implementation, re-run Council
.spec.md = technical only. Business data → stoa-strategy (private repo)

Read the full file on GitHub · 65 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 · 65 lines · 25 tokens per session scan A 9372f6d19111

Subscribe to this mod's changes

spec-driven is a skill published in the GitHub repository stoa-platform/stoa (9 stars, last pushed yesterday), licensed Apache-2.0. It adds 25 tokens to every session and 571 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 2026-08-31.

LLM Planning TDD Testing ai api-management claude enterprise gateway

spec-driven next to 6 skills from other repositories
Mod	Type	Stars	Last push	Licence	Scan	Tokens	Works with
spec-drivenstoa-platform/stoa	Skill	9	yesterday	Apache-2.0	A	25	Claude Code
lyrikgebruder/wirken	Skill	194	2d ago	MIT	A	15	Claude Code
librariangebruder/wirken	Skill	194	2d ago	MIT	A	34	Claude Code
notesgebruder/wirken	Skill	194	2d ago	MIT	A	10	Claude Code
tdx-assetsgebruder/wirken	Skill	194	2d ago	MIT	A	58	Claude Code
aggregatorgebruder/wirken	Skill	194	2d ago	MIT	A	30	Claude Code
githubgebruder/wirken	Skill	194	2d ago	MIT	A	9	Claude Code

stoa: Skill for Claude Code