A0 MCP server

A0

The programming language built for AI, not for people. a0lang.com · Docs

A0 is a compact, exactly specified language that models write and edit through revision-checked structured edits. A model reads only what an edit touches, writes only the changed lines, and nothing invalid lands. One program compiles to native machine code (A0's own AArch64 code generator, or C), the browser (wasm32), JavaScript, the JVM, .NET, Metal GPU kernels, and clocked SystemVerilog, and every target is verified against one oracle.

Measured on the repository's benchmarks (Apple M3, 8 cores, results/*.json). The machine was not quiet: results/exec-benchmark.json records a 1/5/15-minute load average of 6.4-8.0 for the main and arm64 runs and 32-40 for the JavaScript remeasurement; a quiet-machine rerun is pending:

The site a0lang.com is itself two A0 programs (site/page.a0, site/docs.a0).

See DESIGN.md for intent and semantics, MODEL_GUIDE.txt for the AI-facing language instructions, STATUS.md for the current results, loss ledger, known limits, and next actions (session history in docs/history/), and results/ for machine-readable evidence.

Install

A0 is a single self-contained binary: no Node, no Bun.

# macOS / Linux: Homebrew (this repository is the tap; no separate tap repository)
brew tap Joe-Simo/a0 https://github.com/Joe-Simo/a0
brew install a0

# macOS / Linux: script (detects OS/arch, verifies SHA-256, installs to ~/.local/bin)
curl -fsSL https://raw.githubusercontent.com/Joe-Simo/a0/main/install.sh | sh

# Windows (installs to %LOCALAPPDATA%\Programs\a0 and adds it to your user PATH)
irm https://raw.githubusercontent.com/Joe-Simo/a0/main/install.ps1 | iex

Both scripts accept A0VERSION=v0.8.16 to pin a release and A0INSTALL_DIR to change the destination. Or download a binary from the latest release by hand and check it against checksums.txt. a0 --version prints the release and compiler version. Then:

printf 'fn sq u32 -> u32\na mul p0 p0\nret a\nend\n' > sq.a0
a0 run sq.a0 sq 12            # 144
a0 emit arm64 sq.a0           # A0's own machine code; or c, js, java, sv
a0 check sq.a0                # diagnostics with codes; --json for fields, --fix applies the exact fixes
a0 explain A0102              # what a diagnostic means, with a failing and a fixed example

Binaries: a0-darwin-arm64, a0-darwin-x64, a0-linux-x64, a0-linux-arm64, a0-windows-x64.exe. A C compiler (clang or gcc) is needed only to link native output on your machine.

MCP server

Shortened. The full README is on GitHub.