Synapse – Live Plan, Code & Mental Model Mindmap for Any Agent

Synapse is an MCP server + live web viewer that lets any coding agent (Claude Code, Claude Desktop, Cursor, OpenCode, Codex, Windsurf, etc.) maintain a real-time visual mindmap of:

1. What the plan is (hierarchical tasks with planned, in_progress, completed, and blocked statuses)
2. How the agent is thinking about the code (HLD / Mental Model) (semantic component, data_flow, decision, hypothesis, and risk cards connected by directed flow links)
3. Which files and symbols are being touched (line ranges, symbols, diff summaries, and cross-highlighting between plan tasks and architectural components)

📖 Docs: https://vss96.github.io/synapse/

Quick Start

Requires Node ≥ 20.

# Register Synapse with the coding agents installed on this machine
npx synapse-mindmap init

# Watch your agent work (port 4040, or the next free port)
npx synapse-mindmap viewer --open

init detects Claude Code, Claude Desktop, Cursor, OpenCode and Codex (which also covers the ChatGPT desktop app), asks before configuring each one, and backs up any config file it edits. Restart your agent afterwards. Mindmaps are stored in ~/.synapse/data (override with SYNAPSE_DATA_DIR). See the client guide for manual setup, and Updating for getting new releases.

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Screenshots

1. Code Mental Model & High-Level Design (HLD) View

Visualize how the agent understands the system architecture, data flows, design decisions, hypotheses, and risks—without reading walls of text:

2. Split View (Plan Tree + Code Mental Model)

See the full execution plan and the architectural mental model side-by-side in a single live canvas. The Sessions panel on the left lists every mindmap with its active task, progress, and a live dot; filter it or switch with ⌥↑/⌥↓. Press / to find a card, file or symbol on the map:

3. Plan & Tasks View + Changes Tab

The Changes tab shows what kind of change the agent made in each file (added, modified, fixed, refactored, renamed, removed, tested). Pick a kind to highlight every plan task and HLD component with that kind of change:

4. Live Activity Stream

Track a real-time chronological log of every plan update, HLD mapping, and file edit:

5. Archiving Sessions