spec

A specification-first command that records what should be built and how it should be checked before coding begins.

In plain words
What is it for?
Use it to ask clarifying questions and save a SPEC.md file covering the objective, commands, code style, testing approach, and project boundaries.
Why use it?
It reduces misunderstandings about goals, users, features, project structure, tests, technology choices, and limits.

Command for Claude Code

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 commands/addyosmani/agent-skills/spec
Clone the repo
git clone --depth 1 https://github.com/addyosmani/agent-skills

Made for: Claude Code.

Per session 12 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 176 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 $0.00012 $0.00176
Opus 5 $0.00006 $0.00088
Sonnet 5 $0.00002 $0.00035
Haiku 4.5 $0.00001 $0.00018

Measured yesterday against content hash 82325b4cc75a, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

spec 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.

.claude/commands/spec.md · 18 lines

What it actually says

Invoke the agent-skills:spec-driven-development skill.

Begin by understanding what the user wants to build. Ask clarifying questions about:

  1. The objective and target users
  2. Core features and acceptance criteria
  3. Tech stack preferences and constraints
  4. Known boundaries (what to always do, ask first about, and never do)

Then generate a structured spec covering all six core areas: objective, commands, project structure, code style, testing strategy, and boundaries.

If the request bundles several independently testable capabilities, first propose a capability map (module ids, dependency direction, build order) per the skill's Phase 0 and get it approved, then spec each module in dependency order.

Save the spec as SPEC.md in the project root and confirm with the user before proceeding.

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 · 18 lines · 12 tokens per session scan A 82325b4cc75a

Subscribe to this mod's changes

spec is a command published in the GitHub repository addyosmani/agent-skills (90,889 stars, last pushed 3d ago), licensed MIT. It adds 12 tokens to every session and 176 once invoked, about $0.0001 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.