specification-writing

specification-writing is a skill for Claude Code, Codex from Avyayalaya/agent-prime. It costs 56 tokens per session (25,153 once invoked), scanned A, original, MIT.

A framework for writing complete product, feature, API, or agent-task specifications. It aims to make the document detailed enough that an implementer can begin without asking clarification questions.

In plain words
What is it for?
Use it to write specifications with acceptance criteria, scope boundaries, executor context, and clearly marked unresolved decisions.
Why use it?
It exposes assumptions, defines testable outcomes, limits scope, and resolves ambiguities before work starts.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one. Also seen: mentions Codex.

Good fit Use it to write specifications with acceptance criteria, scope boundaries, executor context, and clearly marked unresolved decisions.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/avyayalaya/agent-prime/specification-writing
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 Avyayalaya/agent-prime --skill specification-writing
Clone the repo
git clone --depth 1 https://github.com/Avyayalaya/agent-prime

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 specification-writing

README.md
[![agentmods](https://agentmods.dev/badge/skills/avyayalaya/agent-prime/specification-writing/github.svg)](https://agentmods.dev/skills/avyayalaya/agent-prime/specification-writing)
Your own site
<a href="https://agentmods.dev/skills/avyayalaya/agent-prime/specification-writing"><img src="https://agentmods.dev/badge/skills/avyayalaya/agent-prime/specification-writing/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for specification-writing

Your own site · 80×15
<a href="https://agentmods.dev/skills/avyayalaya/agent-prime/specification-writing"><img src="https://agentmods.dev/badge/skills/avyayalaya/agent-prime/specification-writing.svg" alt="Reviewed on agentmods" width="80" 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 25,153 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 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 $0.25153
Opus 5 $0.00028 $0.12576
Sonnet 5 $0.00011 $0.05031
Haiku 4.5 $0.00006 $0.02515

Measured 9d ago against content hash 23e4fd937c0d, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-09, from the pricing page.

Security

Grade A, and why

specification-writing 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 9d 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.

Origin

Copies of this mod

1 near-identical copy found in the catalogue:

shared/toolkits/skills/specification-writing/SKILL.md · 1,591 lines

How it starts

The opening of the file, as written. The whole thing — 1,591 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Purpose

Produce a Zero-Question Specification — a spec so complete that any competent executor (AI agent, engineer, contractor, cross-functional team) can begin work immediately without asking a single clarifying question.

A Zero-Question Spec is not the same as a long spec. Length is a symptom, not a goal. The goal is that every assumption is surfaced, every ambiguity is resolved or explicitly marked TBD with an owner and deadline, every acceptance criterion is binary-testable, and every scope boundary names the adjacent capability it excludes.

This codex encodes six interlocking frameworks that systematize the transition from "rough feature intent" to "executable specification." Each framework targets a specific class of spec failure. Together, they eliminate the five most common causes of execution failure: unclear outcomes, untestable criteria, invisible scope creep, missing executor context, and silent assumptions.


When to Use / When NOT to Use

When to Use

  • Writing a product or feature spec for a new user-facing capability
  • Writing an API contract spec that multiple teams or services will implement against
  • Writing an agent task spec for an AI agent that will execute autonomously
  • Writing a process or workflow spec that crosses team boundaries
  • Writing an infrastructure or migration spec where failure conditions are critical
  • Writing a research or discovery spec where "done" is ambiguous without explicit criteria
  • Upgrading a draft spec that has already generated clarifying questions from executors
  • Reviewing an existing spec for completeness before handing off to execution

When NOT to Use

  • Brainstorming or ideation — this skill assumes you already know WHAT to build; if you don't, use Problem Framing or Discovery first
  • One-line tickets for well-understood changes — if the executor already has full context and the change is trivial (e.g., "change button color from blue to green"), a zero-question spec is overhead
  • Exploratory prototypes with no success criteria — if the goal is "try things and see what works," a spec constrains prematurely. Use a time-boxed spike instead.
  • Post-hoc documentation — this skill is for BEFORE execution, not for documenting what was already built
  • Specs where the audience is exclusively yourself — the frameworks are calibrated for context transfer to another executor. If you are the sole executor and have full context, a lighter checklist may suffice.

Read the full file on GitHub · 1,591 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. 9d ago First seen · 1,591 lines · 56 tokens per session scan A 23e4fd937c0d

Subscribe to this mod's changes

specification-writing is a skill published in the GitHub repository Avyayalaya/agent-prime (8 stars, last pushed 3mo ago), licensed MIT. It adds 56 tokens to every session and 25,153 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.

Related

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