🧠 Zettelkasten Second Memory

An OpenClaw (2026.4/2026.6+) and Hermes Agent plugin that turns AI conversations into a permanent Zettelkasten knowledge base — atomic notes, bi-directional links, knowledge distillation, and intelligent retrieval via MCP tools.

English · 简体中文

Version OpenClaw Hermes MCP Server License: MIT Node.js Version

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📌 Current Version

Component	Version	Status
Plugin	v1.0.0-beta.8	Active development
Skill	v1.0.0-beta.8	Active development
OpenClaw	2026.4.24/2026.6.x	Developed & tested; compatible with >= 2026.4.23
Hermes Agent	v0.17.0	Experimental support via MCP HTTP bridge
Node.js	>= 22.14.0	Required (for node:sqlite)

Latest Release: v1.0.0-beta.8 — Compatibility adaptation for OpenClaw 2026.6.x and Hermes MCP bridge

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✨ Core Features

Feature	Description
📝 Atomic Notes	Each note is an independent knowledge unit, supporting atomic / structure / source types
🔗 Bi-directional Links	11 semantic link types (supports, refines, extends, contradicts, example-of...) to build a true knowledge graph
🔍 Full-text Search	SQLite FTS5 + LIKE dual engine, supporting Chinese tokenization and fuzzy matching
🤖 AI Integration	Deep MCP integration with OpenClaw and Hermes Agent, enabling AI agents to automatically capture conversation knowledge
🔄 Knowledge Distillation	CEQRC pipeline automatically refines fragmented notes into permanent knowledge
🏷️ Tag System	Flexible tag classification and statistics, supporting tag-cloud analysis
📦 Markdown Native	All notes stored as Markdown, your data belongs entirely to you
🧟 Zombie Detection	Auto-detect stale notes (180+ days, zero backlinks) with zk_find_zombies
✨ Glow Ranking	Knowledge importance scoring via PageRank + citation + recency decay
📦 Archive System	Move cold notes to archive folder; auto-archive nightly at 2:00 AM
📜 Audit Log	Full archive/unarchive history with zk_get_archive_log
🔎 Path Discovery	Weighted shortest path between any two notes with Chinese explanations
🌉 Hermes Bridge	Optional Streamable HTTP MCP bridge exposes all tools to Hermes Agent (v0.17.0+)

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⚡ Performance Benchmark

Tested on: Node.js v22.22.2, SQLite :memory:
Scale: 1,000 notes creation and search | All tests passed ✅
Current suite: 1,724 unit / integration tests with Vitest

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🇨🇳 Looking for Chinese documentation? 点击这里查看简体中文介绍

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📐 System Architecture

graph TD
    OG[OpenClaw Gateway<br/>MCP Protocol Layer]
    HG[Hermes Agent<br/>optional via Streamable HTTP MCP]

    subgraph ZK[Zettelkasten Plugin]
        MT[MCP Tools]
        CLI[CLI Commands]
        S[Service Layer]
        R[Repository Layer]
        ST[Storage Layer]
        C[Core Types]
    end

    DB[(SQLite + Markdown)]

    OG --> MT
    HG --> MT
    MT --> S
    CLI --> S
    S --> R
    R --> ST
    ST --> DB
    C --> S
    C --> R
    C --> ST

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🇨🇳 Looking for Chinese documentation? 点击这里查看简体中文介绍

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🚀 Quick Start

Requirements

• Node.js >= 22.14.0 (requires built-in node:sqlite)
• OpenClaw 2026.4.24/2026.6.x (compatible with >= 2026.4.23)
• Hermes Agent v0.17.0+ (optional, for Hermes integration)

Installation

# Clone the repository
git clone https://github.com/cx2002302-lang/zettelkasten-second-memory.git
cd zettelkasten-second-memory

# Install dependencies
npm install

# Run tests
npm test

Use as an OpenClaw Plugin

# 1. Deploy the plugin
bash scripts/deploy.sh

# 2. Configure OpenClaw (edit ~/.openclaw/openclaw.json)
# Ensure plugins.load.paths includes the plugin path

# 3. Restart the Gateway
openclaw gateway restart

# 4. Initialize the database
openclaw zk init

# 5. Health check
openclaw zk doctor

Use with Hermes Agent (Optional)

# 1. Build the MCP bridge
npm run build:bridge

# 2. Start the bridge (adjust DB/notes paths to your OpenClaw setup)
ZETTELKASTEN_DB_PATH=~/.openclaw/zettelkasten/zettelkasten.db \
ZETTELKASTEN_NOTES_DIR=~/.openclaw/zettelkasten/notes \
ZETTELKASTEN_MCP_PORT=9090 \
node dist/mcp/http-bridge.js

# 3. In your Hermes config, add the MCP server:
# mcp_servers:
#   zettelkasten:
#     type: http
#     url: "http://<openclaw-host>:9090/mcp"
#     enabled: true

# 4. Verify connectivity
hermes mcp test zettelkasten

See docs/COMPATIBILITY.md for version-specific notes.

🛠️ CLI Commands

Command	Description
openclaw zk init	Initialize database and directory structure
openclaw zk doctor	Run health checks
openclaw zk status	Show system status
openclaw zk new	Create a new note
openclaw zk list	List notes
openclaw zk search <query>	Search notes
openclaw zk show <id>	View note details
openclaw zk link <from> <to>	Create a note link
openclaw zk review-stats	View review statistics
openclaw zk review-pending	List pending reviews
openclaw zk feedback-stats	View feedback statistics
openclaw zk prompt-stats	View prompt evolution statistics
openclaw zk curation-stats	View sample curation statistics

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🧩 MCP Tools (for AI Agents)

Tool	Permission	Description
zk_search_notes	Read	Full-text search for notes
zk_get_note	Read	Get a single note
zk_get_backlinks	Read	Get reverse links
zk_find_path	Read	Find paths between notes
zk_create_note	Write	Create a new note
zk_update_note	Write	Update a note
zk_create_link	Write	Create a note link
zk_run_ceqrc	Write	Run the cognitive pipeline
zk_distill_memory	Write	Distill session memories
zk_review_note	Write	Review a note
zk_get_review_panel	Read	Get pending review panel
zk_submit_review	Write	Submit a review
zk_get_review_stats	Read	Get review statistics
zk_submit_feedback	Write	Submit user feedback
zk_get_feedback_stats	Read	Get feedback statistics
zk_analyze_feedback_trends	Read	Analyze feedback trends
zk_get_active_prompt	Read	Get active prompt version
zk_get_prompt_stats	Read	Get prompt evolution stats
zk_get_curation_stats	Read	Get curation statistics
zk_export_samples	Write	Export curated samples

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📁 Project Structure

zettelkasten-second-memory/
├── src/                    # Plugin source code
│   ├── core/               # Type definitions, constants, utilities
│   ├── storage/            # Database schema, FTS5, template manager
│   ├── repository/         # Data access layer (notes, links, tags, reviews...)
│   ├── service/            # Business logic (CEQRC, distillation, deduplication...)
│   ├── integration/        # OpenClaw integration (agent config, scheduler, hooks)
│   ├── mcp/                # MCP tool definitions and server
│   ├── plugin/             # OpenClaw plugin entry and manifest
│   ├── examples/           # Usage examples
│   └── index.ts            # Library entry point
├── skills/brain/           # AI Skill (prompts, rules, workflows)
├── scripts/                # Deployment scripts
├── docs/                   # Documentation
├── package.json
├── LICENSE
└── README.md

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🧠 Second Memory Skill (AI Integration)

This project includes a Brain Skill that enables AI agents to automatically save conversation knowledge into Zettelkasten:

# Install the Skill
cp -r skills/brain ~/.openclaw/skills/zettelkasten-brain

# Activate the Skill
openclaw config set agents.defaults.skills '["zettelkasten-brain"]'

# Restart the Gateway
openclaw gateway restart

Once activated, the AI will automatically:

• 🔍 Search the knowledge base before answering
• 📝 Recognize and save important information
• 🔗 Intelligently establish note associations
• 📦 Archive discussions when sessions end

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📊 Database Schema

The system uses SQLite. Core tables include:

Table	Description
zettel_notes	Main notes table (title, content, status, confidence...)
zettel_links	Bi-directional links table (11 semantic link types)
zettel_tags	Tags table
zettel_note_tags	Note-tag association table
zettel_reviews	Review records table
zettel_feedback	Feedback data table
zettel_prompt_versions	Prompt version table
zettel_meta	Metadata table

FTS5 virtual tables provide full-text search capabilities.

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🧪 Testing

# Run all tests
npm test

Current test coverage:

• Repository layer (CRUD, search, links, tags)
• Service layer (CEQRC, distillation, deduplication, parsing)
• Integration layer (configuration, scheduling)
• MCP Server (tool registration and invocation)

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📜 License

MIT © Zettelkasten Contributors

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🙏 Acknowledgements

• Inspired by Niklas Luhmann's Zettelkasten method
• Built on the OpenClaw plugin architecture
• Uses SQLite FTS5 for full-text search