agentmods.dev

implementation-spec-writer

implementation-spec-writer is a skill for Claude Code, Codex from felipepg22/FPGSkills. It costs 30 tokens per session (179 once invoked), scanned A, original, MIT.

A workflow for writing one self-contained Markdown document that explains exactly how an implementation should be carried out. Markdown is a plain-text document format commonly used for technical specifications.

In plain words
What is it for?
Use it to create or update an agent-ready specification, record assumptions and unresolved decisions, and validate that the document is ready for implementation.
Why use it?
It turns conversation, documents, source code, or repository findings into a clear implementation contract before coding begins.

Skill for Claude CodeCodex

Written for Claude Code and Codex: disable-model-invocation in frontmatter, but also agents/openai.yaml present.

not rated 11repo 8d ago A scan 30 tokens original MIT

Good fit Use it to create or update an agent-ready specification, record assumptions and unresolved decisions, and validate that the document is ready for implementation.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/felipepg22/fpgskills/implementation-spec-writer
View source ↗ felipepg22/FPGSkills
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 felipepg22/FPGSkills --skill implementation-spec-writer
Clone the repo
git clone --depth 1 https://github.com/felipepg22/FPGSkills

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 implementation-spec-writer

README.md
[![agentmods](https://agentmods.dev/badge/skills/felipepg22/fpgskills/implementation-spec-writer/github.svg)](https://agentmods.dev/skills/felipepg22/fpgskills/implementation-spec-writer)
Your own site
<a href="https://agentmods.dev/skills/felipepg22/fpgskills/implementation-spec-writer"><img src="https://agentmods.dev/badge/skills/felipepg22/fpgskills/implementation-spec-writer/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 implementation-spec-writer

Your own site · 80×15
<a href="https://agentmods.dev/skills/felipepg22/fpgskills/implementation-spec-writer"><img src="https://agentmods.dev/badge/skills/felipepg22/fpgskills/implementation-spec-writer.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 30 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 179 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 $0.00030 $0.00179
Opus 5.5 $0.00012 $0.00072
Sonnet 5.5 $0.00006 $0.00036
Haiku 4.5 $0.00003 $0.00018

Measured 2mo ago against content hash 6747f87efed7, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

implementation-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 2mo 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/implementation-spec-writer/SKILL.md · 16 lines

What it actually says

Implementation Spec Writer

Create the implementation contract an engineer or coding agent will execute. Produce the specification only; leave task publication and implementation to separate workflows.

  1. Read references/workflow.md completely and follow its intake, evidence, decision, and write sequence.
  2. Read references/spec-schema.md completely before drafting. Use its document contract and identifiers.
  3. Read references/readiness.md completely before writing. Validate the complete draft against every applicable check.
  4. Create or safely update exactly one Markdown file. Report its path, status, material assumptions, and unresolved decisions.
Files

What ships with it

6 files 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. 2mo ago First seen · 16 lines · 30 tokens per session scan A 6747f87efed7

Subscribe to this mod's changes

implementation-spec-writer is a skill published in the GitHub repository felipepg22/FPGSkills (11 stars, last pushed 8d ago), licensed MIT. It adds 30 tokens to every session and 179 once invoked, about $0.0001 per session on Opus 5.5. 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.

PlanningWriting and docs
Related

implementation-spec-writer compared with skills from other repositories

implementation-spec-writer next to 6 skills from other repositories
ModTypeStarsLast pushLicenceScanTokensWorks with
implementation-spec-writerfelipepg22/FPGSkillsSkill118d agoMITA30Claude Code, Codex
imagegenopenai/codexSkill133kyesterdayApache-2.0A113Codex
playwright-climicrosoft/playwrightSkill99kyesterdayApache-2.0A19Claude Code
local-ai-agentsmicrosoft/ai-agents-for-beginnersSkill79k4d agoMITA200Claude Code, Codex
systematic-debuggingobra/superpowersSkill313k3d agoMITA21Claude Code
next-cache-components-adoptionvercel/next.jsSkill143kyesterdayMITA95Claude Code
next-partial-prefetching-adoptionvercel/next.jsSkill143kyesterdayMITA103Claude Code