A planning mode for complex coding tasks that builds shared understanding through structured discussion before work begins.

Use it when a request needs careful planning, clarification, or agreement on what should happen first.

It gives you a way to clarify goals and think through a task before the coding agent acts on it.

fathom — Plugin by ma-ziwei

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.

Claude Code

/plugin marketplace add ma-ziwei/fathom-mode-for-claude

agentmods

npx agentmods add plugins/ma-ziwei/fathom-mode-for-claude/plugin

Clone the repo

git clone --depth 1 https://github.com/ma-ziwei/fathom-mode-for-claude

Made for: Claude Code.

Per session not measured What this adds to a session before it is invoked.

When invoked not measured Not applicable: nothing here is loaded into a session.

Security scan A 0 findings. Scan, not verified.

Origin original No closer match found in the catalogue.

Security

Grade A, and why

fathom 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.

plugin/.claude-plugin/plugin.json · 12 lines

What it actually says

{
  "name": "fathom",
  "version": "0.1.0",
  "description": "Planning session mode for complex tasks. Enter Fathom Mode to build shared understanding through structured dialogue before execution. Use this when you want to plan, think through, or clarify something complex before acting on it.",
  "author": {
    "name": "Lawrence Ma"
  },
  "license": "MIT",
  "keywords": ["planning", "intent", "clarification", "protocol", "agent-skills"],
  "homepage": "https://github.com/ma-ziwei/fathom-mode-for-claude"
}

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.

2d ago First seen · 12 lines scan A f40daf040c34

Subscribe to this mod's changes

fathom is a plugin published in the GitHub repository ma-ziwei/fathom-mode-for-claude (13 stars, last pushed 4mo ago), licensed MIT. Its token cost is not measured: this kind of file is read by the harness, not the model. 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.

Planning agent-skill agent-skills ai-planning anthropic claude-code claude-cowork

fathom

Getting it into your agent

Grade A, and why

Nothing flagged

What it actually says

What this file has done since we first saw it

Other plugins, from other repositories

MAP Framework Official Marketplace

markifact

roadtrip-skill

swift-focusengine-pro

cowork-os

mixedbread-skills