UltraThink MCP Server

UltraThink MCP Server

A Python MCP server for sequential thinking and problem-solving

Enhanced Python port of the Sequential Thinking MCP Server by Anthropic. Maintains full compatibility while adding confidence scoring, auto-assigned thought numbers, and multi-session support.

[!TIP] Using Claude Code? Install the UltraThink Plugin for seamless integration - no MCP server setup required!

# Via terminal
claude plugin marketplace add husniadil/ekstend
claude plugin install ultrathink@ekstend

# Or interactively in Claude Code
/plugin marketplace add husniadil/ekstend
/plugin install ultrathink@ekstend

[!NOTE] Meta: This MCP server was built iteratively using UltraThink itself - a practical example of the tool's capability to break down complex problems, manage architectural decisions, and maintain context across development sessions.

Features

• UltraThink: Break down complex problems into manageable steps
• Dynamic Adjustments: Revise and refine thoughts as understanding deepens
• Branching: Explore alternative paths of reasoning
• Confidence Scoring: Explicit uncertainty tracking (0.0-1.0 scale)
• Auto-adjustment: Automatically adjusts total thoughts if needed
• Multi-Session Support: Manage multiple concurrent thinking sessions with session IDs
• Formatted Logging: Colored terminal output with rich formatting (can be disabled)
• 100% Test Coverage: Comprehensive test suite with full code coverage
• Type Safety: Full mypy strict mode type checking for production code
• Simple Layered Architecture: Clean separation with models, services, and interface layers

Installation

Quick Install (Recommended)

Run directly with uvx from GitHub (no installation needed):

uvx --from git+https://github.com/husniadil/ultrathink ultrathink

Development Setup

For local development:

# Clone the repository
git clone https://github.com/husniadil/ultrathink.git
cd ultrathink

# Install all dependencies (including dev dependencies)
uv sync

Usage

Task Commands (npm-like)

# List all available tasks
uv run task --list

# Run the server
uv run task run

# Run tests with coverage
uv run task test

# Run tests without coverage (quick)
uv run task test-quick

# Run the test client
uv run task client

# Format code (ruff + prettier)
uv run task format

# Lint code
uv run task lint

# Type check with mypy
uv run task typecheck

# Clean cache files
uv run task clean

Direct Commands (Alternative)

For direct execution without task runner:

# Run the server directly
uv run ultrathink

# Run the test client directly
uv run python examples/client.py

Note: For testing, linting, and formatting, prefer using uv run task commands shown above.

Tool: ultrathink

The server provides a single tool for dynamic and reflective problem-solving through structured thinking.

Parameters

Required:

• thought (str): Your current thinking step
• total_thoughts (int): Estimated total thoughts needed (>=1)

Optional:

• thought_number (int): Current thought number - auto-assigned sequentially if omitted (1, 2, 3...), or provide explicit number for branching/semantic control
• next_thought_needed (bool): Whether another thought step is needed. Auto-assigned as thought_number < total_thoughts if omitted. Set explicitly to override default behavior
• session_id (str): Session identifier for managing multiple thinking sessions (None = create new, provide ID to continue session)
• is_revision (bool): Whether this revises previous thinking
• revises_thought (int): Which thought number is being reconsidered
• branch_from_thought (int): Branching point thought number
• branch_id (str): Branch identifier
• needs_more_thoughts (bool): If more thoughts are needed
• confidence (float): Confidence level (0.0-1.0, e.g., 0.7 for 70% confident)
• uncertainty_notes (str): Optional explanation for doubts or concerns about this thought
• outcome (str): What was achieved or expected as result of this thought
• assumptions (list[Assumption]): Assumptions made in this thought (id, text, confidence, critical, verifiable)
• depends_on_assumptions (list[str]): Assumption IDs this thought depends on (e.g., ["A