index1

AI memory system for coding agents — code index + cognitive facts, persistent across sessions.

AI memory system for coding agents with BM25 + vector hybrid search. Provides 6 MCP tools for intelligent code/doc search and cognitive fact recording.

What it does

• Dual memory: corpus (code index) + cognition (episodic facts)
• Hybrid search: BM25 full-text + vector semantic search with RRF fusion
• Structure-aware chunking: Markdown, Python, Rust, JavaScript, plain text
• MCP Server: 6 tools (recall, learn, read, status, reindex, config)
• CJK optimized: Chinese/Japanese/Korean query detection with dynamic weight tuning
• Built-in ONNX embedding: Vector search works out of the box, no Ollama required
• Graceful degradation: Works without any embedding service (BM25-only mode)

Install

# Recommended
pipx install index1

# Or via pip
pip install index1

# Or via npm (auto-installs Python package)
npx index1@latest

One-click plugin setup:

index1 setup                 # Auto-configure hooks + MCP for Claude Code

Verify:

index1 --version
index1 doctor        # Check environment

Setup MCP

Create .mcp.json in your project root:

{
  "mcpServers": {
    "index1": {
      "type": "stdio",
      "command": "index1",
      "args": ["serve"]
    }
  }
}

If index1 is not in PATH, use the full path from which index1.

Add Search Rules

Add to your project's .claude/CLAUDE.md:

## Search Strategy

This project has index1 MCP Server configured (recall + 5 other tools). When searching code:

1. Known identifiers (function/class/file names) -> Grep/Glob directly (4ms)
2. Exploratory questions ("how does XX work") -> recall first, then Grep for details
3. CJK query for English code -> must use recall (Grep can't cross languages)
4. High-frequency keywords (50+ expected matches) -> prefer recall (saves 90%+ context)

Impact:

Without rules: Grep "search" -> 881 lines -> 35,895 tokens
With rules:    recall        -> 5 summaries -> 460 tokens (97% savings)

Index Your Project

index1 index ./src ./docs    # Index source and docs
index1 status                # Check index stats
index1 search "your query"   # Test search

Optional: Multilingual Enhancement

index1 v2 has built-in ONNX embedding (bge-small-en-v1.5). For better multilingual support:

curl -fsSL https://ollama.com/install.sh | sh
ollama pull nomic-embed-text           # Standard, 270MB
# or
ollama pull bge-m3                     # Best for CJK, 1.2GB

index1 config embed_backend ollama
index1 doctor                          # Verify setup

Without Ollama, ONNX embedding provides vector search out of the box.

Web UI

index1 web                   # Start Web UI on port 6888
index1 web --port 8080       # Custom port

MCP Tools Reference

Tool	Description
recall	Unified search — code + cognitive facts, BM25 + vector hybrid
learn	Record insights, decisions, lessons learned (auto-classify + dedup)
read	Read file content + index metadata
status	Index and cognition statistics
reindex	Rebuild index for a path or collection
config	View or modify configuration

Troubleshooting

Issue	Fix
Tools not showing	Check .mcp.json format and index1 path
AI doesn't use recall	Add search rules to CLAUDE.md
command not found	Use full path from which index1
Chinese search returns 0	Install Ollama + bge-m3 model
No vector search	Built-in ONNX should work; run index1 doctor