spec

spec is a skill for Claude Code, Codex from epicsagas/epic-harness. It costs 37 tokens per session (764 once invoked), scanned A, original, Apache-2.0.

A requirements-writing workflow that turns a software request into a numbered specification with testable acceptance criteria.

In plain words
What is it for?
Use it to clarify vague requests, document what is included and excluded, record technical constraints, and save an approved specification for later work.
Why use it?
It makes the intended behavior, boundaries, and proof of completion explicit before implementation begins.

Skill for Claude CodeCodex

Part of the epic plugin — 27 skills, 6 hooks shipped together

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/epicsagas/epic-harness/spec
Any agent
npx skills add epicsagas/epic-harness --skill spec
Clone the repo
git clone --depth 1 https://github.com/epicsagas/epic-harness

Made for: Claude Code, Codex.

Or install epic, the plugin that ships this one along with the rest of its 27 skills, 6 hooks.

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

README.md
[![agentmods](https://agentmods.dev/badge/skills/epicsagas/epic-harness/spec.svg)](https://agentmods.dev/skills/epicsagas/epic-harness/spec)
Your own site
<a href="https://agentmods.dev/skills/epicsagas/epic-harness/spec"><img src="https://agentmods.dev/badge/skills/epicsagas/epic-harness/spec.svg" alt="Measured on agentmods" height="20"></a>
Per session 37 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 764 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 $0.00037 $0.00764
Opus 5 $0.00018 $0.00382
Sonnet 5 $0.00007 $0.00153
Haiku 4.5 $0.00004 $0.00076

Measured 5d ago against content hash 7514461f3a95, 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 5d 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/SKILL.md · 88 lines

How it starts

The opening of the file, as written. The whole thing — 88 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Spec — Define What to Build

CRITICAL: Run HARNESS_DIR=$(epic-harness path) first. NEVER use .harness/ in the project directory.

Process

  1. Understand the request

    • Read any existing context (CLAUDE.md, README, codebase structure)
    • If the request is vague, ask focused questions (max 3 at a time)
    • Never assume — clarify ambiguity before proceeding
  2. Produce the spec Write a concise spec covering:

    • Goal: One sentence — what does this achieve?
    • Scope: What's included and explicitly excluded
    • Requirements: Numbered list (R1, R2, ...) of concrete, testable behaviors
    • Acceptance criteria: Numbered list (AC1, AC2, ...) — observable outcomes that prove each requirement is met
    • Technical notes: Constraints, dependencies, edge cases
  3. Confirm with user Show the spec in digestible chunks. Get explicit approval before proceeding.

Output

Save the approved spec to $HARNESS_DIR/specs/SPEC-{timestamp}.md using this exact format:

---
status: approved
created: {ISO-8601 timestamp}
goal_slug: {kebab-case-goal-summary}
---

# SPEC-{timestamp}: {Goal}

## Goal
{One sentence}

## Scope
- In: {what is included}
- Out: {what is explicitly excluded}

## Requirements
- R1: {concrete testable behavior}
- R2: {concrete testable behavior}

## Acceptance Criteria
- AC1 (R1): {observable outcome proving R1}
- AC2 (R2): {observable outcome proving R2}

## Technical Notes
{Constraints, dependencies, edge cases}

After saving:

  1. Count the Requirements (R1, R2, ...). If 3 or more, check team status: epic team status.
    • If no team is linked: suggest "This spec has N requirements. Consider running /team to set up a project-specific agent team before /go."
    • If a team is already linked: skip this hint.
  2. Tell the user: "Spec saved. Run /go to start building."

Anti-Rationalization

Excuse Rebuttal What to do instead
"It's a small change, I'll just code it" Small changes still have wrong assumptions Write the spec — it takes 2 minutes
"I'll refine the spec after coding" Spec after code is documentation, not planning Spec first, code second
"The user didn't give me enough detail" Then ask — don't invent requirements Ask focused questions, max 3 at a time

Read the full file on GitHub · 88 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. 5d ago First seen · 88 lines · 37 tokens per session scan A 7514461f3a95

Subscribe to this mod's changes

spec is a skill published in the GitHub repository epicsagas/epic-harness (18 stars, last pushed today), licensed Apache-2.0. It adds 37 tokens to every session and 764 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 2026-08-30.