spec-writer

A specification-writing assistant that starts from a Claude design URL and works out the product requirements behind it. It fills in backend, data, and business logic details, plans epics and sprint issues, and keeps a local specs/ folder as the main reference.

In plain words
What is it for?
Use it to analyse a Claude design, define acceptance criteria, plan an epic and sprint issues, and maintain the project’s local specification documents.
Why use it?
A design usually shows screens but not the complete behavior behind them. This helps turn visual designs into concrete implementation requirements and trackable development tasks.

Agent 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 agents/gpwork4u/specflow/spec-writer
Clone the repo
git clone --depth 1 https://github.com/gpwork4u/specflow

Made for: Claude Code.

Per session 86 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 2,670 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin unknown 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 $0.00086 $0.02670
Opus 5 $0.00043 $0.01335
Sonnet 5 $0.00017 $0.00534
Haiku 4.5 $0.00009 $0.00267

Measured yesterday against content hash 13f8db208297, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

spec-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 yesterday.

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/agents/spec-writer.md · 133 lines

The source is not reproduced here

No licence file

A repository with no LICENSE is all rights reserved by default, so the body is not copied here. The metadata, the measurements and the link are.

Read it on GitHub

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. yesterday First seen · 133 lines · 86 tokens per session scan A 13f8db208297

Subscribe to this mod's changes

spec-writer is an agent published in the GitHub repository gpwork4u/specflow (5 stars, last pushed 3mo ago), with no licence file. It adds 86 tokens to every session and 2,670 once invoked, about $0.0004 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.