lumen — Agent Skill

Claude reads entire files to find what it needs. Lumen gives it a map.

Lumen is a 100% local semantic code search engine for AI coding agents. No API keys, no cloud, no external database, just open-source embedding models (Ollama or LM Studio), SQLite, and your CPU. A single static binary and your own local embedding server.

The payoff is measurable and reproducible: across 9 benchmark runs on 9 languages and real GitHub bug-fix tasks, Lumen cuts cost in every single language — up to 39%. Output tokens drop by up to 66%, sessions complete up to 53% faster, and patch quality is maintained in every task. All verified with a transparent, open-source benchmark framework that you can run yourself.

| | With Lumen | Baseline (no Lumen) | | ---------------------- | ----------------------------- | -------------------- | | Cost (avg, bug-fix) | $0.29 (-26%) | $0.40 | | Time (avg, bug-fix) | 125s (-28%) | 174s | | Output tokens (avg) | 5,247 (-37%) | 8,323 | | JavaScript (marked) | $0.32, 119s (-33%, -53%) | $0.48, 255s | | Rust (toml) | $0.38, 204s (-39%, -34%) | $0.61, 310s | | PHP (monolog) | $0.14, 34s (-27%, -34%) | $0.19, 52s | | TypeScript (commander) | $0.14, 56s (-27%, -33%) | $0.19, 84s | | Svelte (chat-ui) | $0.10, 56s (-26%, -31%) | $0.14, 80s | | Patch quality | Maintained in all 9 tasks | — |

Table of contents

• Demo
• Quick start
• What you get
• How it works
• Benchmarks
• Supported languages
• Configuration
• Supported embedding models
• Controlling what gets indexed
• Database location
• CLI Reference
• Troubleshooting
• Development

Demo

_Claude Code asking about the Prometheus codebase. Lumen's semantic_search finds the relevant code without reading entire files._

Quick start

Prerequisites:

Platform support: Linux, macOS, and Windows. File locking for background indexing coordination uses flock(2) on Unix and LockFileEx on Windows (via gofrs/flock).

1. Ollama installed and running, then pull the default

embedding model:

   ollama pull ordis/jina-embeddings-v2-base-code