henrychong-ai

Yggdrasil MCP — Development skill for Claude Code

Development community

Reasoning orchestration MCP server — Tree of Thoughts with deep planning, branching, and revision.

How to install Yggdrasil MCP

This entry records only its repository, not the path inside it, so there is no exact command to give. Open henrychong-ai/yggdrasil-mcp and copy the folder into ~/.claude/skills/, or the file into ~/.claude/agents/.

What Yggdrasil MCP does

Reasoning orchestration MCP server — Tree of Thoughts with deep planning, branching, and revision. Drop-in replacement for sequential-thinking with critical Claude Code string coercion fix. Works with Claude Code, Claude Desktop, and any MCP client.

Alternatives in Development

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Om Dump — Freeform capture mode 4.6k ★

README

Yggdrasil MCP

[![npm version](https://img.shields.io/npm/v/yggdrasil-mcp.svg)](https://www.npmjs.com/package/yggdrasil-mcp) [![CI](https://github.com/henrychong-ai/yggdrasil-mcp/actions/workflows/ci-cd.yml/badge.svg)](https://github.com/henrychong-ai/yggdrasil-mcp/actions/workflows/ci-cd.yml) [![License: MIT](https://img.shields.io/badge/License-MIT-yellow.svg)](https://opensource.org/licenses/MIT) [![Node.js](https://img.shields.io/badge/Node.js-%3E%3D24-green.svg)](https://nodejs.org/)

**Reasoning orchestration MCP server** — Tree of Thoughts with multi-agent evaluation.

A fork of Anthropic's `@modelcontextprotocol/server-sequential-thinking` with critical bug fixes and an ambitious roadmap for advanced reasoning capabilities.

Why Yggdrasil?

In Norse mythology, Yggdrasil is the World Tree connecting all realms. This MCP embodies that metaphor:

Branches = Different reasoning paths through possibility space
Roots = Deep foundational analysis (first principles)
Connections = Links between thoughts, revisions, and evaluations

Key Features

Current (v1.1.0)

6 MCP tools — sequential_thinking, deep_planning, list_plans, get_plan, promote_plan, archive_plans
Descriptive plan naming — Optional planName parameter generates dp-YYYYMMDD-{name} session IDs with duplicate detection
Plan lifecycle management — Promote Claude Code orphan plans, archive old plans, unified discovery across both systems
deep_planning tool — Structured multi-phase planning sessions (init → clarify → explore → evaluate → finalize)
Session resumption — Resume planning sessions by ID with JSONL persistence
Hybrid persistence — JSONL event log + Markdown plan export with JSON index
String coercion fix — Fixes Claude Code bug #3084 where MCP parameters are incorrect