spec-driven-development

spec-driven-development is a skill for Claude Code, Codex from ChrisLamDev/hermes-core-skills. It costs 38 tokens per session (1,520 once invoked), scanned A, original, MIT.

A development process that writes and reviews a clear specification before planning tasks and coding. The specification records what will be built and how completion will be checked.

In plain words
What is it for?
Use it for new projects, larger features, architectural decisions, or requests that need requirements clarified before implementation.
Why use it?
It reduces guesswork when starting a project or when requirements are vague, incomplete, or spread across several changes.

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/chrislamdev/hermes-core-skills/spec-driven-development
Any agent
npx skills add ChrisLamDev/hermes-core-skills --skill spec-driven-development
Clone the repo
git clone --depth 1 https://github.com/ChrisLamDev/hermes-core-skills

Made for: Claude Code, Codex.

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.

agentmods badge for spec-driven-development

README.md
[![agentmods](https://agentmods.dev/badge/skills/chrislamdev/hermes-core-skills/spec-driven-development.svg)](https://agentmods.dev/skills/chrislamdev/hermes-core-skills/spec-driven-development)
Your own site
<a href="https://agentmods.dev/skills/chrislamdev/hermes-core-skills/spec-driven-development"><img src="https://agentmods.dev/badge/skills/chrislamdev/hermes-core-skills/spec-driven-development.svg" alt="Measured on agentmods" height="20"></a>
Per session 38 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,520 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 $0.00038 $0.01520
Opus 5 $0.00019 $0.00760
Sonnet 5 $0.00008 $0.00304
Haiku 4.5 $0.00004 $0.00152

Measured 3d ago against content hash 12d3e0b437c8, 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 3d 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.

skills/spec-driven-development/SKILL.md · 200 lines

How it starts

The opening of the file, as written. The whole thing — 200 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 between you and Chris — it defines what we're building, why, and how we'll know it's done. Code without a spec is guessing.

When to Use

  • Starting a new project or feature
  • Requirements are ambiguous or incomplete (e.g. "make it better", "add more features")
  • The change touches multiple files or modules
  • You're about to make an architectural decision
  • The task would take more than 15 minutes to implement

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

The Gated Workflow

Spec-driven development has four phases. Do not advance to the next phase until the current one is validated.

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

Phase 1: Specify

Start with a high-level vision. Ask Chris clarifying questions until requirements are concrete.

Surface assumptions immediately. Before writing any spec content, list what you're assuming:

ASSUMPTIONS I'M MAKING:
1. This is a WeChat Mini Program (not a web app)
2. Data is stored locally (not on a server)
3. We use Cocos Creator 3.x for the game engine
4. Target users are Chinese-speaking Buddhists, including elderly
→ Correct me now or I'll proceed with these.

Write a spec document covering these six core areas:

  1. Objective — What are we building and why? Who is the user? What does success look like?

  2. Commands — Full executable commands with flags, not just tool names.

    Build: npm run build
    Test: npx jest --passWithNoTests
    Verify: npm run compile
    
  3. Project Structure — Where source code lives, where tests go, where docs belong.

    assets/        → Game assets (images, audio, fonts)
    src/           → Application source code
    src/scenes/    → Cocos Creator scenes
    src/scripts/   → TypeScript game scripts
    

Read the full file on GitHub · 200 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. 3d ago First seen · 200 lines · 38 tokens per session scan A 12d3e0b437c8

Subscribe to this mod's changes

spec-driven-development is a skill published in the GitHub repository ChrisLamDev/hermes-core-skills (9 stars, last pushed 2mo ago), licensed MIT. It adds 38 tokens to every session and 1,520 once invoked, about $0.0002 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.