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The Bert compiler and its agent skill, built from commit 21b384a95-dirty — the version this site runs. Nothing else is published.

What you need

  • node 22.18 or newer runs the compiler, which ships as TypeScript source. Bert is tested on Node 24.
  • wasmtime runs the programs you build, and serves websites.
  • wasm-tools 1.227 packages components, so you need it only for the component target, such as a web server.

This page assumes Node.js is installed, and Homebrew too on macOS. Work through the steps in order; each block is meant to be pasted into a terminal as it stands.

1. Install wasmtime and wasm-tools

Linux

wasmtime's installer puts it in ~/.wasmtime and adds it to your shell profile. wasm-tools is a single binary, picked for your CPU (x86_64 or aarch64):

curl https://wasmtime.dev/install.sh -sSf | bash

mkdir -p ~/.local/bin
curl -fsSL https://github.com/bytecodealliance/wasm-tools/releases/download/v1.227.1/wasm-tools-1.227.1-$(uname -m)-linux.tar.gz \
  | tar -xz --strip-components=1 -C ~/.local/bin wasm-tools-1.227.1-$(uname -m)-linux/wasm-tools

macOS

brew install wasmtime wasm-tools

2. Install the compiler

Tip

Choose one way. Paste the commands, or download the file and unpack it yourself. Either puts the compiler in ~/.bert, so you do not need both.

Option A: from the terminal

rm -rf ~/.bert && mkdir -p ~/.bert
curl -fsSL http://mannes-mbp.tailf477ee.ts.net/static/downloads/bert-cli.tgz | tar -xz -C ~/.bert

Option B: from the browser

Then unpack it, assuming your browser saved it to ~/Downloads:

rm -rf ~/.bert && mkdir -p ~/.bert
tar -xz -C ~/.bert -f ~/Downloads/bert-cli.tgz

Then put bert on your PATH

On Linux with bash, ~/.local/bin is where wasm-tools went:

echo 'export PATH="$HOME/.bert/bin:$HOME/.local/bin:$PATH"' >> ~/.bashrc

On macOS with zsh:

echo 'export PATH="$HOME/.bert/bin:$PATH"' >> ~/.zprofile

Open a new terminal, so the new PATH takes effect, and check that it works as below.

3. Install the skill (optional)

A language guide and library reference that teaches a coding agent to write Bert. It is a Claude Code skill, and goes in ~/.claude/skills/bert.

Tip

Choose one way. Paste the commands, or download the file and unpack it yourself, as for the compiler.

Option A: from the terminal

rm -rf ~/.claude/skills/bert && mkdir -p ~/.claude/skills/bert
curl -fsSL http://mannes-mbp.tailf477ee.ts.net/static/downloads/bert-skill.tgz | tar -xz -C ~/.claude/skills/bert

Option B: from the browser

Then unpack it:

rm -rf ~/.claude/skills/bert && mkdir -p ~/.claude/skills/bert
tar -xz -C ~/.claude/skills/bert -f ~/Downloads/bert-skill.tgz

Check that it works

A project is a directory with a bert.toml, which may be empty. This one prints Hello, Bert! and exits:

mkdir hello && cd hello
touch bert.toml
cat > hello.bert <<'EOF'
external export {
  _start : () -> Unit
  _start = () -> WasiCli.print("Hello, Bert!\n")
}
EOF
bert hello.bert

To update, repeat steps 2 and 3: they replace the old copy. cat ~/.bert/VERSION shows which commit you have.