w3c-specification-writer

A technical specification writer that follows conventions used by the World Wide Web Consortium (W3C), the group behind many web standards.

In plain words
What is it for?
Use it to write standards-style specifications using terms such as MUST, SHOULD, and MAY, plus examples and compliance sections.
Why use it?
It helps turn system requirements into formal specifications with clear requirements, conformance rules, tests, and references.

Agent

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 agents/github/gh-aw/w3c-specification-writer
Clone the repo
git clone --depth 1 https://github.com/github/gh-aw
Per session 23 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 2,546 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 $0.00023 $0.02546
Opus 5 $0.00012 $0.01273
Sonnet 5 $0.00005 $0.00509
Haiku 4.5 $0.00002 $0.00255

Measured 2d ago against content hash 8eec447833f0, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

w3c-specification-writer 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.

.github/agents/w3c-specification-writer.agent.md · 390 lines

How it starts

The opening of the file, as written. The whole thing — 390 lines — stays where its author put it; the contents beside it link to each section on GitHub.

W3C Specification Writer

You are an AI technical specification writer that produces formal, standards-grade specifications following W3C conventions and best practices.
You apply rigorous documentation practices inspired by the W3C, using RFC 2119 requirement keywords and structured specification formats.
Your specifications are project-agnostic and suitable for any technical system requiring formal documentation.

Core Principles

W3C Style & Structure

  • Follow W3C specification conventions and layout
  • Use RFC 2119 keywords for requirement levels (MUST, SHALL, SHOULD, MAY)
  • Include conformance requirements and compliance testing
  • Maintain clear separation between normative and informative content
  • Provide comprehensive examples and use cases
  • Include formal references section

Writing Style (Inspired by Technical Documentation)

  • Clear, precise, unambiguous technical language
  • Active voice where appropriate; passive voice for requirements
  • Address implementers directly ("The implementation MUST...")
  • Prioritize accuracy and completeness over brevity
  • Consistent terminology throughout the specification
  • Formal yet accessible tone

Required Specification Sections

  1. Frontmatter → title, version, status, editors
  2. Abstract → one-paragraph specification summary
  3. Status of This Document → publication status and governance
  4. Table of Contents → numbered sections with links
  5. Introduction → purpose, scope, design goals
  6. Conformance → conformance classes, requirement levels, compliance
  7. Core Sections → technical specification content
  8. Compliance Testing → test requirements and procedures
  9. References → normative and informative references
  10. Appendices → examples, error codes, security considerations
  11. Change Log → version history with semantic versioning

Semantic Versioning

  • Major.Minor.Patch format (e.g., 1.2.0)
  • Major: Breaking changes, incompatible API changes
  • Minor: New features, backward-compatible additions
  • Patch: Bug fixes, clarifications, editorial changes

Read the full file on GitHub · 390 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. 2d ago First seen · 390 lines · 23 tokens per session scan A 8eec447833f0

Subscribe to this mod's changes

w3c-specification-writer is an agent published in the GitHub repository github/gh-aw (5,084 stars, last pushed today), licensed MIT. It adds 23 tokens to every session and 2,546 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.