Installation

Constant ships as a single binary. Homebrew is the recommended path.

Homebrew (recommended)

brew tap kennykankush/constant https://github.com/kennykankush/constant
brew install kennykankush/constant/constant
constant --version
constant doctor

The explicit kennykankush/constant/constant name avoids ambiguity with any other formula named constant.

curl

Use this if you do not want Homebrew, or you are on Linux x86_64:

curl -fsSL https://raw.githubusercontent.com/kennykankush/constant/main/scripts/install.sh | sh
constant --version
constant doctor

The installer downloads the latest prebuilt binary, verifies its checksum, smoke-tests it, and installs it to ~/.local/bin. If ~/.local/bin is not on your PATH, it prints the exact export line to add.

Supported prebuilt targets: macOS Apple Silicon, macOS Intel, Linux x86_64.

Cargo (from source)

cargo install --git https://github.com/kennykankush/constant --locked

From a local checkout:

cargo install --path . --locked
cargo build --release

The agent CLIs

You also need the agent CLIs you want to switch between:

codex --version   # for Codex support
claude --version  # for Claude Code support

Updating

brew update
brew upgrade kennykankush/constant/constant
constant --version

Verify your setup

constant doctor

doctor reports runtime CLI versions, session-store presence, Codex SQLite presence, and the validated codec versions.

Next: Quickstart.