LeanCTX Compresses Agent File Reads to ~13 Tokens on a Cache Hit

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LeanCTX (3,630 stars, pushed 2026-08-22) is a single local Rust binary that acts as an MCP server and context router for coding agents, installed against Claude Code with `lean-ctx wrap claude`. Published benchmarks on a 50-file repo claim 98.1% compression in map mode (533K to 8K tokens) and 96.7% in signatures mode, with cached re-reads costing roughly 13 tokens against ~2,000 for a fresh read, at about 3,000 tokens of session overhead. It exposes read modes (`full`, `map`, `signatures`, `diff`), a live savings dashboard via `lean-ctx gain --live`, and `lean-ctx benchmark report` so you can verify the numbers on your own repo rather than trusting the README.