Madar: Local Context Compiler for Claude Code / Cursor — 78% Fewer Tokens on NestJS Repo

Madar is an open-source local context compiler for coding agents like Claude Code, Cursor, Copilot, and Gemini. It maps your TypeScript/Node.js repo once (locally, with no ML dependencies) and serves a minimal context pack via MCP for each query, avoiding the agent's default per-session rediscovery of the codebase.

How It Works

Install globally and generate a graph scoped to your backend service using --spi (single package isolation):

npm i -g @lubab/madar
madar generate . --spi
madar claude install   # or: madar cursor install / madar copilot install

The tool is deterministic — pure static analysis of imports and call paths, no embeddings, no model calls.

Benchmark on NestJS + BullMQ (~800 files)

The same question ("how is the idea report generated") was asked to Claude Code with and without Madar. Numbers from Anthropic's reporting:

• Input tokens: 1,000,776 (plain) → 223,539 (with Madar) — 78% reduction
• Cost: $1.84 → $0.69 — 63% savings
• Turns: 16 → 5
• Tool calls: 15 → 4

Where It Backfires

The author is transparent about limitations:

• Only tested on one repo, one agent, one question type ("how does X work"). Not a general claim.
• Scoping is critical: using --spi on a single service worked; pointing it at a whole monorepo produced context packs that could increase token usage.
• Edit/review tasks are not yet validated — the win is for explain-type queries.
• Only works for TypeScript/Node.js codebases currently.

Who It's For

Developers working on large NestJS, Express, or Node.js repos who rely on AI coding agents and want to cut token waste on repetitive context-gathering. Not suitable for monorepos without careful scoping.