Install

One command. crab is deliberately not published to crates.io yet — the name is a one-way door — so the installer builds it from the repository for you.

macOS & Linux

$curl -fsSL https://crabagent.ai/install.sh | sh

Checks for a Rust toolchain, builds from main, and warns you if ~/.cargo/bin is missing from PATH.

It is safe to re-run: it uses cargo install --force, which replaces the binary in place. That is also the upgrade path.

$ crab --version
crab 0.4.0

No Rust toolchain, or you want a binary with no build step? Take a tarball from Releases — see prebuilt binaries below.

Or build from a clone

If you want the source, or you are working on crab itself. The workspace pins its toolchain in rust-toolchain.toml (rustfmt and clippy included).

git clone https://github.com/jinpeng/crab-agent
cd crab-agent
cargo install --path crates/crab-cli

Two gotchas worth knowing:

Re-installing the same version needs --force: cargo install --force --path crates/crab-cli.
cargo install --git … re-resolves every dependency from crates.io, so it needs network even when a local build already works.

Prebuilt binaries

Releases ship tarballs for macOS aarch64-apple-darwin, Linux x86_64-unknown-linux-gnu and aarch64-unknown-linux-gnu. Asset names encode both version and target triple.

Requirements

To build: A Rust toolchain; the exact channel is pinned in rust-toolchain.toml.
To run: None. No Node, no Python, no JVM.
Network: Outbound HTTPS to your provider's base_url, plus web_fetch targets if you use that tool.
Shell: bash must exist for the bash tool. It is not needed for the interactive UI.

Before the first run

You can start with one environment variable:

export CRAB_API_KEY=sk-...
crab

With no config file at all, crab talks to https://api.openai.com/v1 with gpt-4o-mini. To use anything else, write ~/.crab/config.toml:

default_provider = "deepseek"

[providers.deepseek]
base_url       = "https://api.deepseek.com/v1"
model          = "deepseek-chat"
api_key        = "sk-..."          # optional if CRAB_API_KEY is set
context_window = 128000

Environment variables beat the profile field by field, so the same config works on a build machine with a different key. See Providers & models for the full resolution order.

The config holds secrets. Keep it out of any directory you point the agent at, prefer short-lived keys, and remember that environment variables are inherited by bash calls — if a key is in your shell, the agent can read it with env.

Upgrade

Re-run the same command — the script replaces the installed binary in place:

curl -fsSL https://crabagent.ai/install.sh | sh

From a clone, git pull && cargo install --force --path crates/crab-cli does the same thing.

Config and sessions survive an upgrade. Session format changes bump format_version; a file without a meta row is treated as version 1 (pre-observability) rather than guessed at.

Remove

cargo uninstall --path crates/crab-cli
rm -rf ~/.crab          # config and the pricing overlay
rm -rf ./.crab          # this project's sessions and metrics ledger

The last two delete your usage history. Export it first if you care — crab metrics --json > metrics.json is a complete dump of the ledger.

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