spec-driven-development

A workflow for writing a clear specification before coding. A specification records what is being built, why it is needed, and how completion will be checked; TDD-like review gates here mean a person reviews the scope, plan, tasks, and implementation at each stage.

In plain words
What is it for?
Use it for new projects, larger features, architectural decisions, and requirements involving several independently testable capabilities. It is not intended for simple fixes or obvious one-line changes.
Why use it?
It reduces confusion when requirements are vague or a change affects several parts of a project. It creates a shared reference before implementation begins.

Skill for Claude CodeCodex

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.

agentmods
npx agentmods add skills/oleg494/coding-kit/spec-driven-development
Any agent
npx skills add oleg494/coding-kit --skill spec-driven-development
Clone the repo
git clone --depth 1 https://github.com/oleg494/coding-kit

Made for: Claude Code, Codex.

Per session 55 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 958 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
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.

ModelPer sessionOnce invoked
Fable 5 $0.00055 $0.00958
Opus 5 $0.00028 $0.00479
Sonnet 5 $0.00011 $0.00192
Haiku 4.5 $0.00006 $0.00096

Measured yesterday against content hash 20fac38d0486, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

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 yesterday.

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.

skills/spec-driven-development/SKILL.md · 147 lines

How it starts

The opening of the file, as written. The whole thing — 147 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Spec-Driven Development

Overview

Write a structured specification before writing any code. The spec is the shared source of truth — it defines what we're building, why, and how we'll know it's done.

When to Use

  • Starting a new project or feature
  • Requirements are ambiguous or incomplete
  • The change touches multiple files or modules
  • You're about to make an architectural decision
  • The task would take more than 30 minutes to implement

When NOT to use: Single-line fixes, typo corrections, or changes where requirements are unambiguous.

The Gated Workflow

SPECIFY ──→ PLAN ──→ TASKS ──→ IMPLEMENT
   │          │        │          │
   ▼          ▼        ▼          ▼
 Human      Human    Human      Human
 reviews    reviews  reviews    reviews

Phase 0: Scope Check (multi-capability only)

If a single requirement bundles several independently testable capabilities → propose a capability map first:

# Capability Map: [Initiative Name]
| Module id | Responsibility | Depends on |
|---|---|---|
| identity | Accounts, sessions, SSO | — |
| billing | Plans, invoices, payments | identity |
| notifications | Email and webhook fan-out | identity |

Build order: identity → billing, notifications.

Phase 1: Specify

Surface assumptions immediately:

ASSUMPTIONS I'M MAKING:
1. This is a web application (not native mobile)
2. Authentication uses session-based cookies (not JWT)
3. The database is PostgreSQL
→ Correct me now or I'll proceed with these.

Spec template (6 core areas):

# Spec: [Project/Feature Name]

## Objective
[What we're building and why. User stories or acceptance criteria.]

## Tech Stack
[Framework, language, key dependencies with versions]

## Commands
[Build, test, lint, dev — full commands]

## Project Structure
[Directory layout with descriptions]

## Code Style
[Example snippet + key conventions]

## Testing Strategy
[Framework, test locations, coverage requirements, test levels]

## Boundaries
- Always: [Run tests before commits, follow naming conventions, validate inputs]
- Ask first: [DB schema changes, adding dependencies, changing CI config]
- Never: [Commit secrets, edit vendor directories, remove failing tests]

## Success Criteria
[How we'll know this is done — specific, testable conditions]

## Open Questions
[Anything unresolved that needs human input]

Read the full file on GitHub · 147 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.

  1. yesterday First seen · 147 lines · 55 tokens per session scan A 20fac38d0486

Subscribe to this mod's changes

spec-driven-development is a skill published in the GitHub repository oleg494/coding-kit (1 stars, last pushed yesterday), licensed MIT. It adds 55 tokens to every session and 958 once invoked, about $0.0003 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.

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