spec-anchored-agentic-development: Skill for Claude Code

.agents/skills/to-spec/SKILL.md

to-spec is a skill for Claude Code, Codex from w00fx/spec-anchored-agentic-development. It costs 101 tokens per session (943 once invoked), scanned A, original, MIT.

A specification-writing skill that turns an interview, conversation, notes, or transcript into structured capability documents. Missing information is recorded as open questions instead of being guessed.

In plain words
What is it for?
It helps create or update Markdown specifications with defined terms, requirements, acceptance tests, and citations from the available material.
Why use it?
It removes the need to manually format scattered decisions into requirements, acceptance criteria, and stable identifiers.

Skill for Claude CodeCodex

Written for Claude Code and Codex: disable-model-invocation in frontmatter, but also agents/openai.yaml present. Also seen: installed under .agents/ (shared by several agents).

This is w00fx/spec-anchored-agentic-development's own configuration. It tells Claude Code and Codex how to work on spec-anchored-agentic-development itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything spec-anchored-agentic-development configures →

Reuse

Borrowing it

Nothing to install: this file belongs to w00fx/spec-anchored-agentic-development. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file
curl -O https://raw.githubusercontent.com/w00fx/spec-anchored-agentic-development/main/.agents/skills/to-spec/SKILL.md
Clone the repo
git clone --depth 1 https://github.com/w00fx/spec-anchored-agentic-development

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 to-spec

README.md
[![agentmods](https://agentmods.dev/badge/skills/w00fx/spec-anchored-agentic-development/to-spec.svg)](https://agentmods.dev/skills/w00fx/spec-anchored-agentic-development/to-spec)
Your own site
<a href="https://agentmods.dev/skills/w00fx/spec-anchored-agentic-development/to-spec"><img src="https://agentmods.dev/badge/skills/w00fx/spec-anchored-agentic-development/to-spec.svg" alt="Measured on agentmods" height="20"></a>
Per session 101 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 943 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 $0.00101 $0.00943
Opus 5 $0.00051 $0.00472
Sonnet 5 $0.00020 $0.00189
Haiku 4.5 $0.00010 $0.00094

Measured 3d ago against content hash c873acaa7f26, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade A, and why

to-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 3d 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.

.agents/skills/to-spec/SKILL.md · 80 lines

How it starts

The opening of the file, as written. The whole thing — 80 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Turn the material in this conversation — a shape session is the common case — into the capability spec. If pointed at notes or a transcript instead, work from those. This skill does not interview: the questions already happened. If material for a template section is missing, list it under Open questions — ask nothing, invent nothing, default nothing silently.

Write

  1. Identify the capability (the argument, or the session's subject). Resolve its one stable logical-contract entrypoint at specs/<capability>/<capability>.md, using spec-templates/capability-spec.md. The entrypoint may later declare companion files without creating another authority.
  2. Create mode (no spec exists yet): fill every template section from the resolved material — Capability language as an opinionated glossary (canonical term; _Avoid_: synonyms; what it IS, not what it does); normative behavior in the representation its truth type demands (EARS as the default; decision tables, state models, formulas+oracles, schemas per the template's matrix), each externally-sourced rule with its citation (identifier + version + scope); Acceptance criteria in Given/When/Then, each with its typed stable ID; reference-value rows for every calculation; Non-goals with teeth; Contracts and dependencies.
  3. Update mode (the spec exists): produce the delta — new rules, new items get typed IDs issued in continuation (the ID is the addressing scheme; tickets point at it), new or changed reference rows, non-goal updates. Never renumber or rewrite existing criteria unless the interview explicitly resolved a change to them.
  4. Large reference tables (beyond a screen) go to specs/<capability>/tables/ as data files the golden tests read; the rule cites the file.

The completeness pass (writer-side — the interrogation was shape's)

Before reporting done:

  • Every template section is either filled or explicitly represented in Open questions.
  • Oracle coverage: every rule has an executable expression (reference values → golden; GWT → tests) or is explicitly marked human-judgment territory.
  • Every externally-sourced rule carries its citation.
  • The spec stays layer-agnostic: no deployment targets, no framework names, no file paths — behavior and business truth only (the how lives in plans and ADRs).

Read the full file on GitHub · 80 lines

Files

What ships with it

1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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. 3d ago First seen · 80 lines · 101 tokens per session scan A c873acaa7f26

Subscribe to this mod's changes

to-spec is a skill published in the GitHub repository w00fx/spec-anchored-agentic-development (5 stars, last pushed 5d ago), licensed MIT. It adds 101 tokens to every session and 943 once invoked, about $0.0005 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 2026-09-05.