Quickstart

Follow this page top to bottom. You go from nothing to one finished task.

Install#

Pick one way to install.

With Homebrew:

brew install hisea/tap/radian

From a release tarball. Download radian-<version>-<target>.tar.gz and its .sha256 file from the releases page. Check the file first, then unpack it:

shasum -a 256 -c radian-<version>-<target>.tar.gz.sha256
tar -xzf radian-<version>-<target>.tar.gz
./radian --version

From source with Cargo:

cargo install --git https://github.com/hisea/radian radian-tui

On Linux the sandboxed tier needs bubblewrap. Install it first, for example with sudo apt install bubblewrap on Debian and Ubuntu.

Connect a model#

Radian needs a model endpoint and a stored key. Run the login wizard:

radian login

Pick your provider from the numbered list. Type the key when asked. The key never echoes. Radian checks the key with one read-only request before it saves anything. The key lands in ~/.radian/credentials/auth.json. Nothing else in that file changes.

You can also keep the key in an environment variable. Store $OPENAI_API_KEY as the key value instead of the literal key. Radian resolves the reference on every run, so the secret stays out of the file. See providers for the full login, endpoint, and model rules.

Every run names three things: --provider, --model, and --base-url. The provider picks the wire format: openai-compatible or anthropic. The model is a bare name, never provider/model. The base URL is everything before the provider path. Omit --base-url to use the provider public endpoint.

A worked OpenAI-compatible session:

export OPENAI_API_KEY=sk-...
radian exec --provider openai-compatible --model gpt-5 -p "summarize Cargo.toml"

A worked Anthropic session:

radian exec --provider anthropic --model claude-opus-4-6 --max-tokens 16384 -p "summarize Cargo.toml"

Anthropic needs --max-tokens because its API requires the field. The default is 16384. The flag has no meaning for openai-compatible requests and is refused there.

First session#

Open the full-screen interface:

radian

You see an input box and an empty transcript. Type a task and press Enter. Radian reads files, searches code, and edits with built-in tools: read, write, patch, glob, grep, shell, job, memory_search, ask_user, skill, and subagent. Each tool call shows in the transcript with its arguments and its result. Watch one run: ask for a summary of the project, and follow each read as it prints.

Press Esc to cancel a running turn. Answer y to allow a tool question once, a to allow it for the session, anything else to deny it. Press Ctrl-C twice to quit. The session file stays on disk.

Resume a session#

List this workspace sessions:

radian exec --list

Resume one by id:

radian exec --resume <id> -p "continue where we left off"

In the full-screen interface, pass --resume <id> to reopen it there. A goal that was active comes back paused; type /goal resume to continue it.

Run one headless task#

radian exec -p runs one task and exits. Stdout carries only the model text, so you can pipe it. Status and errors go to stderr. The exit code tells how the turn ended: 0 for done, 3 for an exhausted budget, 4 for an unfinished answer. See cli for every flag and every exit code.

radian exec --provider openai-compatible --model gpt-5 -p "list every TODO in src/"

Where files live#

Radian keeps its state under ~/.radian/. Set RADIAN_HOME to move the whole tree. Sessions live in ~/.radian/sessions. Credentials live in ~/.radian/credentials/auth.json. The configuration file is ~/.radian/config/config.toml. Pass --session-dir <dir> or set RADIAN_SESSION_DIR to move sessions only. See configuration for the file format and environment for every variable.

Next steps#

  • Read commands to learn the slash commands: /help, /compact, /model, /sessions, /memory.
  • Read permissions before you run in an unfamiliar repository: full is the default tier, workspace sandboxes the run.
  • Read cli when you need a flag you have not seen here.
  • Read troubleshooting when a request fails with an auth error or a tool refuses a path.
  • Ask radian about radian in plain words: it reads this same manual through radian docs.