What is yggdrasil-mcp?

A Claude plugin that adds branching reasoning, detailed planning, and tools for managing saved plans. It connects Claude to an MCP server, a standard interface for AI tools and outside services.

Use it for sequential thinking, deep planning, listing or viewing plans, promoting a plan, and archiving plans.

It helps organize complex reasoning into possible paths and keep plans available for later use.

yggdrasil-mcp — Plugin for Claude Code by henrychong-ai

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.

Clone the repo

git clone --depth 1 https://github.com/henrychong-ai/yggdrasil-mcp

Made for: Claude Code.

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.

README.md

[![agentmods](https://agentmods.dev/badge/plugins/henrychong-ai/yggdrasil-mcp/cowork-plugin/github.svg)](https://agentmods.dev/plugins/henrychong-ai/yggdrasil-mcp/cowork-plugin)

Your own site

<a href="https://agentmods.dev/plugins/henrychong-ai/yggdrasil-mcp/cowork-plugin"><img src="https://agentmods.dev/badge/plugins/henrychong-ai/yggdrasil-mcp/cowork-plugin/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.

Your own site · 80×15

<a href="https://agentmods.dev/plugins/henrychong-ai/yggdrasil-mcp/cowork-plugin"><img src="https://agentmods.dev/badge/plugins/henrychong-ai/yggdrasil-mcp/cowork-plugin.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

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. A grade says what 26 rules found in the file — not that it is safe.

Origin original No closer match found in the catalogue.

Security

Grade A, and why

yggdrasil-mcp 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 9d 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.

cowork-plugin/.claude-plugin/plugin.json · 15 lines

What it actually says

{
  "name": "yggdrasil-mcp",
  "description": "Tree of Thoughts reasoning, deep planning, and plan management for Claude. Adds sequential_thinking, deep_planning, list_plans, get_plan, promote_plan, archive_plans.",
  "version": "1.2.10",
  "author": {
    "name": "Henry Chong",
    "email": "[email protected]",
    "url": "https://github.com/henrychong-ai"
  },
  "homepage": "https://github.com/henrychong-ai/yggdrasil-mcp",
  "repository": "https://github.com/henrychong-ai/yggdrasil-mcp",
  "license": "MIT",
  "keywords": ["reasoning", "planning", "sequential-thinking", "tree-of-thoughts", "mcp"]
}

Contents

What it installs

The manifest is a name and a version. 1 MCP server travel with it, and installing the plugin installs all of them. Each is measured on its own page, and each can be installed alone.

MCP server yggdrasil A not measured

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.

9d ago First seen · 15 lines scan A 31b84fe1122a

Subscribe to this mod's changes

yggdrasil-mcp is a plugin published in the GitHub repository henrychong-ai/yggdrasil-mcp (3 stars, last pushed 6d 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 2026-08-31.

Building agents Claude Code Planning ai ai-reasoning anthropic chain-of-thought claude

before-you-build

Pre-build product risk review for founders, product teams, and AI-assisted builders before implementation starts.

wshobson/agents · not measured

go-ultimate

Opinionated Go development skill — architecture, conventions, production readiness, repo/CI hygiene, review, and MCP/agent patterns.

Djarvur/go-ultimate · not measured

sipcode

Token-economy observatory for Claude Code: forensic per-session audit, A/B savings verifier, reproducible benchmark, and cost prediction — directly in Claude chat. Auto-installs via npx on first use; no separate npm install required.

Anuj7411/sipcode · not measured

aio-visual-diff

Verify AI-built UI against design via measurement-driven diff — extracts computed CSS and bounding boxes through Chrome DevTools MCP, diffs against Figma reference or a frozen baseline, and feeds numerical deltas back to the agent. No screenshot eyeballing.

aiocean/claude-plugins · not measured

claude-bestpractice

Enforcement, memory and parallel-session coordination for solo founders running several Claude Code sessions on one repository.

avanturer/claude-bestpractice · not measured

claude-webcache

Cross-session WebFetch cache for Claude Code. WebFetches disappear after 15 minutes — claude-webcache makes them persist.

theYahia/claude-webcache · not measured