1DesignTool does not ship with its own model — the design work is done by a coding-agent CLI already on your machine. Connecting one is a one-time step: the app scans for the supported CLIs, you pick which to drive, and the agent itself handles sign-in against your own account.
How connecting works
Open the agent picker — in onboarding, or later under Settings → Agents or the Claude Code · Default chip in the composer. The list shows the CLIs the app found on this machine: Claude Code, Codex, Cursor Agent, Grok, OpenCode, Antigravity, Qwen, Kimi, Amp, Devin, Cline, Hermes, Pi, Oh My Pi, Kiro and Aider. An agent that is installed but not signed in shows its status, and 1DesignTool hands you off to that CLI's own sign-in — your credentials never go through the app.
Once connected, the agent becomes the studio's engine: every run, steer, variant and fix goes through it as a headless subprocess inside your project folder, using your plan and your quota.
Pick a default — switch any time
The composer chip shows the active agent and model, and you can switch per project or per run. Different agents have different strengths — the docs per agent (e.g. Design with Claude Code) cover what each one is good at and the model options it exposes.
Tip: Set the strongest agent you have as the default, then use Council mode on the runs that matter — it fans the brief out to multiple reviewers and returns a checked result, not just a draft.
Your account, your quota
Every turn bills to the agent account you signed in — 1DesignTool meters tokens and shows the running cost in the usage pill and under Settings → Usage, but it never touches the billing itself. An agent without quota, or with a lapsed sign-in, fails the run visibly rather than silently falling back.