spec-driven-development

spec-driven-development is a skill for Claude Code, Codex from bolivian-peru/os-moda. It costs 56 tokens per session (1,802 once invoked), scanned A, original, Apache-2.0.

A software development workflow based on writing a specification before building a larger feature. TDD, or test-driven development, uses tests as a repeated signal that the implementation works.

In plain words
What is it for?
Use it for features spanning several files when you want documented requirements, technical planning, task breakdowns, and implementation guided by tests.
Why use it?
It turns a broad request into agreed requirements, a plan, tasks, code, and tests that can be reviewed as the work progresses.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Use it for features spanning several files when you want documented requirements, technical planning, task breakdowns, and implementation guided by tests.

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Install with agentmods
npx agentmods add skills/bolivian-peru/os-moda/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 bolivian-peru/os-moda --skill spec-driven-development
Clone the repo
git clone --depth 1 https://github.com/bolivian-peru/os-moda

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/bolivian-peru/os-moda/spec-driven-development.svg)](https://agentmods.dev/skills/bolivian-peru/os-moda/spec-driven-development)
Your own site
<a href="https://agentmods.dev/skills/bolivian-peru/os-moda/spec-driven-development"><img src="https://agentmods.dev/badge/skills/bolivian-peru/os-moda/spec-driven-development.svg" alt="Measured on agentmods" height="20"></a>
Per session 56 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,802 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. Third-party audits
  • NVIDIA SkillSpector pass 7 Sept 2026
How audits are shown
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 5.1 $0.00056 $0.01802
Opus 5 $0.00028 $0.00901
Sonnet 5 $0.00011 $0.00360
Haiku 4.5 $0.00006 $0.00180

Measured 7d ago against content hash 31244b0cebf4, 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 7d 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 · 171 lines

How it starts

The opening of the file, as written. The whole thing — 171 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Spec-Driven Development Skill

You ship software through GitHub's spec-kit (92K stars, MIT, baked into every osModa spawn). The workflow makes you a closed loop: humans declare WHAT and WHY; you generate plan, tasks, code; tests are the inner-loop signal of success; the human is the outer-loop reviewer.

When to invoke spec-kit

Use spec-kit when:

  • The user asks for a feature implementation: "build me X", "add Y", "implement Z", "rewrite this so it does W"
  • The work spans more than ~5 file edits
  • Tests will exist that you can iterate against
  • The user wants a reproducible artifact trail (specs, plans, tasks)

Skip spec-kit when:

  • One-line fix or typo
  • Operational task: use system-monitor, self-healing, app-deployer instead
  • Exploratory hack: free-form chat
  • The user explicitly says "just edit the file" / "don't write a spec"

The 8-step workflow

# Skill Purpose
1 speckit-constitution Project governance: code style, test policy, language choice
2 speckit-specify What & why (no tech stack yet). User stories with priorities.
3 speckit-clarify (optional) Ask user for gaps before locking the plan
4 speckit-plan Tech stack + architecture choices
5 speckit-tasks Ordered actionable task list
6 speckit-analyze (optional) Cross-artifact consistency check
7 speckit-checklist (optional) Quality gates before implement
8 speckit-implement Generate code, run tests, iterate until green

How to call from your tool box

The two MCP tools spec_kit_init + spec_kit_run wrap the spec-kit workflow. Use them — don't shell out to specify directly. Tool calls are audit-ledgered; raw shell isn't.

Step 1 — scaffold

spec_kit_init({
  project_name: "csv-exporter",
  integration: "claude",
  constitution_seed: "Python 3.12+, pytest for tests, no async, single binary"
})

Returns { project_path: "/workspace/csv-exporter", skills: [9 speckit-*], next_action }. The 9 skills become available as /speckit-* slash commands inside that project.

Read the full file on GitHub · 171 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. 7d ago First seen · 171 lines · 56 tokens per session scan A 31244b0cebf4

Subscribe to this mod's changes

spec-driven-development is a skill published in the GitHub repository bolivian-peru/os-moda (117 stars, last pushed 2mo ago), licensed Apache-2.0. It adds 56 tokens to every session and 1,802 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 2026-08-30.