Sequential Thinking MCP Server

A Model Context Protocol (MCP) server providing a structured thinking journal: schema-validated thoughts, an append-only audit trail, structural analysis, and session export/import. It records and organizes a thinking process through defined stages — it does not evaluate, generate, or improve the reasoning itself; that stays with whatever model is calling it.

Features

• Structured Thinking Framework: Organizes thoughts through standard cognitive stages (Problem Definition, Research, Analysis, Synthesis, Conclusion), with warnings (or, in --strict-stages mode, rejection) when a thought skips or backtracks a stage
• Revisions & Branching: Revise earlier thoughts or fork alternative lines of reasoning, with revision- and branch-aware analysis and summaries
• Thought Tracking: Records and manages sequential thoughts with metadata as a structured, typed audit trail (structured_content on every tool response)
• Related Thought Analysis: Finds thoughts that are lexically similar to the current one, independent of stage, plus a separate same-tag/same-stage grouping — a categorical signal, not a claim of semantic relevance
• Progress Monitoring: Explicit mainline position, total recorded thoughts, branch count, and revision count — not a single ambiguous percentage
• Summary Generation: Extracts the actual recorded thinking (per-stage excerpts, aggregated challenged assumptions, open branches, revision chains) alongside structural statistics — a deterministic extraction, not new reasoning
• Persistent Storage: Append-only JSONL session log with thread-safety and automatic crash recovery
• Data Import/Export: Share and reuse thinking sessions
• Extensible Architecture: Easily customize and extend functionality
• Robust Error Handling: Protocol/validation errors (bad stage, duplicate thought number, path traversal) fail the call outright; execution errors the caller can adapt to come back as a normal tool result
• Type Safety: Comprehensive type annotations (mypy --strict clean) and Pydantic validation, including declared output schemas for every tool

Prerequisites

• Python 3.10 or higher
• UV package manager (Install Guide)

Key Technologies

• Pydantic: For data validation, serialization, and structured tool output schemas
• Portalocker: For thread-safe file access
• MCP Python SDK 2.x (mcp.server.mcpserver.MCPServer): For Model Context Protocol integration

Project Structure