aptu-coder

Standalone MCP server for code structure analysis using tree-sitter. OpenSSF silver certified: fewer than 1% of open source projects reach this level.

[!NOTE] Native agent tools (regex search, path matching, file reading) handle targeted lookups well. aptu-coder handles the mechanical, non-AI work: mapping directory structure, extracting symbols, and tracing call graphs. Offloading this to a dedicated tool reduces token usage and speeds up coding with better accuracy.

Benchmarks

Auth migration task on Claude Code against Django (Python) source tree. Full methodology.

Mode	Sonnet 4.6	Haiku 4.5
MCP	112k tokens, $0.39	406k tokens, $0.42
Native	276k tokens, $0.95	473k tokens, $0.53
Savings	59% fewer tokens, 59% cheaper	14% fewer tokens, 21% cheaper

AeroDyn integration audit task on Claude Code against OpenFAST (Fortran) source tree. Full methodology.

Mode	Sonnet 4.6	Haiku 4.5
MCP	472k tokens, $1.65	687k tokens, $0.72
Native	877k tokens, $2.85	2162k tokens, $2.21
Savings	46% fewer tokens, 42% cheaper	68% fewer tokens, 68% cheaper

Overview

aptu-coder is a Model Context Protocol server that gives AI agents precise structural context about a codebase: directory trees, symbol definitions, and call graphs, without reading raw files. It supports 18 languages (see Supported Languages) and integrates with any MCP-compatible orchestrator.

Supported Languages

Language	Extensions
Astro	.astro
C/C++	.c, .cc, .cpp, .cxx, .h, .hpp, .hxx
C#	.cs
CSS	.css
Fortran	.f, .f77, .f90, .f95, .f03, .f08, .for, .ftn
Go	.go
HTML	.html, .htm
Java	.java
JavaScript	.js, .mjs, .cjs
JSON	.json
Kotlin	.kt, .kts
Markdown	.md, .mdx
Python	.py
Rust	.rs
TOML	.toml
TSX	.tsx
TypeScript	.ts
YAML	.yaml, .yml

Installation

Homebrew (macOS and Linux)

brew install clouatre-labs/tap/aptu-coder

Update: brew upgrade aptu-coder

cargo-binstall (no Rust required)

cargo binstall aptu-coder

cargo install (requires Rust toolchain)

cargo install aptu-coder

Quick Start

Build from source

cargo build --release

The binary is at target/release/aptu-coder.

Configure MCP Client

Two transports are available. Streamable HTTP is recommended when using orchestrators that spawn delegates (e.g. goose coder): a single server process is shared across the orchestrator and all agents, eliminating extension-drift that occurs when each stdio subprocess gets its own isolated instance.

Streamable HTTP (recommended for multi-agent setups)

With Homebrew, one command starts the server on login and keeps it running:

brew services start aptu-coder