spec

A workflow for writing a structured software specification before coding begins. It clarifies the goal, users, features, technical choices, tests, and project boundaries.

In plain words
What is it for?
Use it to ask targeted questions, define acceptance criteria, plan the project structure and testing approach, and save the result as a specification in the project's documentation.
Why use it?
It turns an unclear request into agreed requirements and records important decisions before implementation starts, reducing misunderstandings during development.

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/ghosteken/agent-harness/spec
Clone the repo
git clone --depth 1 https://github.com/Ghosteken/agent-harness

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 318 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 $0.00318
Opus 5 $0.00006 $0.00159
Sonnet 5 $0.00002 $0.00064
Haiku 4.5 $0.00001 $0.00032

Measured 2d ago against content hash 71a1aaabd782, 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 2d 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.

.claude/commands/spec.md · 18 lines

What it actually says

Invoke the agent-harness: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)

Whenever a clarifying question or open question has a small set of distinct answers (a choice between approaches, yes/no, pick-one-of-N), ask it with the AskUserQuestion tool instead of printing it as text — including the "Open Questions" checkpoint before implementation starts. Only fall back to plain text for questions that genuinely need a freeform answer.

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

Save every spec under docs/specs/<feature-slug>/SPEC.md. If docs/, docs/specs/, or the feature's subfolder don't exist yet, create them — that's the standard home for specs in this project, not the project root. Check whether a spec folder for this feature already exists before writing — if so, confirm with the user whether to update it in place or create a new one (e.g. docs/specs/<feature-slug>-2/SPEC.md). Never overwrite an unrelated existing spec by defaulting to a generic root-level SPEC.md. Confirm the chosen path and content 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. 2d ago First seen · 18 lines · 12 tokens per session scan A 71a1aaabd782

Subscribe to this mod's changes

spec is a command published in the GitHub repository Ghosteken/agent-harness (2 stars, last pushed 16d ago), licensed MIT. It adds 12 tokens to every session and 318 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 2026-08-31.