spec-driven-development

spec-driven-development is a skill for Claude Code, Codex from b-mendoza/agent-skills. It costs 67 tokens per session (2,586 once invoked), scanned A, original, no licence file.

A workflow that writes a specification before coding a new project, feature, or major change. A specification is a written description of what should be built and how its requirements should be understood.

In plain words
What is it for?
Starting projects or significant changes, clarifying unclear requirements, and creating a written spec before writing code.
Why use it?
It helps turn vague or ambiguous requirements into an agreed plan before implementation begins.

Skill for Claude CodeCodex

Which agent this was written for is unclear — body not stored (licence); the path alone says nothing. Also seen: installed under .agents/ (shared by several agents).

Good fit Starting projects or significant changes, clarifying unclear requirements, and creating a written spec before writing code.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/b-mendoza/agent-skills/spec-driven-development
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.

Any agent
npx skills add b-mendoza/agent-skills --skill spec-driven-development
Clone the repo
git clone --depth 1 https://github.com/b-mendoza/agent-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/b-mendoza/agent-skills/spec-driven-development.svg)](https://agentmods.dev/skills/b-mendoza/agent-skills/spec-driven-development)
Your own site
<a href="https://agentmods.dev/skills/b-mendoza/agent-skills/spec-driven-development"><img src="https://agentmods.dev/badge/skills/b-mendoza/agent-skills/spec-driven-development.svg" alt="Measured on agentmods" height="20"></a>
Per session 67 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,586 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 unknown 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 5.1 $0.00067 $0.02586
Opus 5 $0.00034 $0.01293
Sonnet 5 $0.00013 $0.00517
Haiku 4.5 $0.00007 $0.00259

Measured 3d ago against content hash 615ff006266a, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-07, 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.

.agents/skills/spec-driven-development/SKILL.md · 246 lines

The source is not reproduced here

No licence file

A repository with no LICENSE is all rights reserved by default, so the body is not copied here. The metadata, the measurements and the link are.

Read it on GitHub

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 Changed · +39 lines · +24 tokens per session 615ff006266a
  2. 7d ago First seen · 207 lines · 43 tokens per session scan A af5b873414a8

Subscribe to this mod's changes

spec-driven-development is a skill published in the GitHub repository b-mendoza/agent-skills (1 stars, last pushed yesterday), with no licence file. It adds 67 tokens to every session and 2,586 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.