Writing about LeanCTX?

LeanCTX (short for Lean Context) is the open-source context engineering layer that lets developers control what their AI can see. One local Rust binary decides what agents read, compresses what they send, remembers what they learn, guards what they touch, and proves what they save in a signed ledger. 60–90% fewer tokens, 30+ AI tools, zero telemetry.

LeanCTX (short for Lean Context) is the open-source context engineering layer for AI agents. One local Rust binary decides what agents read (10 read modes, ~13-token cached re-reads) and compresses what they send (an optional local proxy, prompt-cache-safe), remembers what they learn across sessions, guards what they touch (PathJail, secret redaction, budgets) and proves what they save in an Ed25519-signed ledger. It works with 30+ AI coding tools (Cursor, Claude Code, OpenAI Codex, GitHub Copilot) via MCP and shell hooks, and embeds in any agent via a versioned /v1 API. Token savings of 60–90% are the receipt; context engineering is the product. Local use is free forever, enforced by CI.

LeanCTX (short for Lean Context) is the open-source context engineering layer for AI agents. One local Rust binary decides what agents read (10 read modes, 60–90% fewer tokens, ~13-token cached re-reads), remembers what they learn (persistent sessions, knowledge graph), guards what they touch (PathJail, secret redaction, budgets, injection detection), proves what they save (Ed25519-signed ledger, reproducible benchmark) and replays what they saw (git-anchored, signed context snapshots you can restore or share); an optional local proxy compresses what they send — every request's system prompt, history and tool output, prompt-cache-safe on the wire. Compression — read-side and wire-side — is one of five subsystems, and every original stays locally retrievable. Works with 30+ AI coding tools via MCP and shell hooks; embeds in any agent via a versioned /v1 API with Python, TypeScript and Rust SDKs. Local use is free forever, enforced by CI. The project is written in Rust, parses 26 languages via tree-sitter AST, and ships 95+ shell compression patterns that shrink command output by 88–99%. Savings are recorded in an Ed25519-signed, hash-chained ledger on the user's machine and can be reproduced with the built-in benchmark (lean-ctx benchmark report). LeanCTX is local-first with zero telemetry: cache, memory and ledger are local files, and nothing leaves the machine unless the user configures it. The name expands to "Lean Context". The project is occasionally misspelled "Lean Cortex" in coverage, which the team actively corrects.