implement-plan

implement-plan is a skill for Claude Code from coalesce-labs/catalyst. It costs 64 tokens per session (4,324 once invoked), scanned A, original, no licence file.

A coding-agent add-on for carrying out approved implementation plans. It uses TDD, or test-driven development, where a failing test is written first, the code is made to pass, and then the code is cleaned up.

In plain words
What is it for?
Building features or fixes from plans in thoughts/shared/plans/, including parallel work in team mode.
Why use it?
It turns an agreed plan into code while using tests to check each change and expose mistakes early.

Skill for Claude Code

Written for Claude Code: allowed-tools in frontmatter.

Installs and runs on its own, but its text points at files inside its plugin — anything it tells you to read at a ${CLAUDE_PLUGIN_ROOT} path is only there once the plugin is installed. Installing the plugin gets both.

Part of the catalyst-dev plugin — 31 skills, 9 agents shipped together

Good fit Building features or fixes from plans in thoughts/shared/plans/, including parallel work in team mode.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/coalesce-labs/catalyst/implement-plan
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 coalesce-labs/catalyst --skill implement-plan
Clone the repo
git clone --depth 1 https://github.com/coalesce-labs/catalyst

Made for: Claude Code.

Or install catalyst-dev, the plugin that ships this one along with the rest of its 31 skills, 9 agents.

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 implement-plan

README.md
[![agentmods](https://agentmods.dev/badge/skills/coalesce-labs/catalyst/implement-plan.svg)](https://agentmods.dev/skills/coalesce-labs/catalyst/implement-plan)
Your own site
<a href="https://agentmods.dev/skills/coalesce-labs/catalyst/implement-plan"><img src="https://agentmods.dev/badge/skills/coalesce-labs/catalyst/implement-plan.svg" alt="Measured on agentmods" height="20"></a>
Per session 64 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 4,324 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 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 5.1 $0.00064 $0.04324
Opus 5 $0.00032 $0.02162
Sonnet 5 $0.00013 $0.00865
Haiku 4.5 $0.00006 $0.00432

Measured 7d ago against content hash 19c6ddbbe858, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-07, from the pricing page.

Security

Grade A, and why

implement-plan 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 7d 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.

plugins/dev/skills/implement-plan/SKILL.md · 420 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. 7d ago First seen · 420 lines · 64 tokens per session scan A 19c6ddbbe858

Subscribe to this mod's changes

implement-plan is a skill published in the GitHub repository coalesce-labs/catalyst (20 stars, last pushed 2d ago), with no licence file. It adds 64 tokens to every session and 4,324 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 2026-08-30.

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