AI

The AI tab sets up the AI that runs Limn’s reviews, fixes and summaries. Limn runs on your own Claude or Codex account: there is no Limn AI service in between. This tab says which provider runs by default, whether each one is ready and signed in, how hard the AI works, how much of your plan Limn may use on its own, and how much disk space AI runs take. Every setting here applies to you in every workspace.

#Choose the provider

Automatic runs and default has three choices: Auto, Claude and Codex. The provider you pick runs every automatic run (auto review, auto fix, the ticket and CI reviews, diagrams and the summaries) and every AI feature that has no model menu. Auto uses Claude when both are signed in, and otherwise whichever one is.

AI Review and AI Fix have their own model menu. When both Claude and Codex are signed in, the menu lists both and starts on this provider. When both are signed in, reviews run on both by default; see Claude and Codex together.

A change applies to the next run. A run already going finishes on the provider it started on, and every run keeps the name of the provider and model that ran it.

#Set up and sign in

Limn downloads Claude and Codex by itself the first time it starts. Signing in is the only step. The tab shows one line for each provider:

Claude

Limn uses your Claude Code login on this computer. Run claude in a terminal and sign in there. When there is no login, Limn uses an Anthropic API key set as ANTHROPIC_API_KEY when Limn starts. The line then reads Signed in to Claude Code. or Using ANTHROPIC_API_KEY., or asks you to sign in. Full details: Claude (Anthropic).

Codex

Codex signs in with your ChatGPT account, in Limn’s own folder. Your own Codex setup is not used, and neither is an OpenAI API key.

1. Select Sign in with ChatGPT.
2. Select Open the ChatGPT sign-in and finish signing in in your browser. On a computer with no browser, select Use a code instead and enter the code on the page it names.
3. The line changes to Signed in with ChatGPT. (or names your ChatGPT plan).

Sign out removes Limn’s Codex sign-in. Full details: Codex (OpenAI).

#Use my API keys first

Tick Use my API keys first to pay for AI runs with an API key instead of your subscription. Limn reads the keys from the environment it started in (your shell, or the .env file), and never stores one. The line under the box says which keys are set.

• Claude reads ANTHROPIC_API_KEY. With the box ticked and the key set, every Claude run uses the key, even while you are signed in to Claude Code. Anthropic bills it per token, and Limn shows its spend in US$. With the box not ticked, Limn uses your Claude Code sign-in, and the key only when you are not signed in.
• Codex reads OPENAI_API_KEY. Codex runs on an API key are not available yet, so Codex keeps using your ChatGPT sign-in.

Starting Limn with LIMN_AI_USE_API_KEY=true or false decides it from the environment, and the box shows that value, locked.

#Effort

Effort for reviews and AI Fix sets how hard the AI works. Higher effort reads more and finds more, and uses more of your plan or costs more. It applies to every review (AI Review, the CI review, the story check and Check threads), AI Fix and Implement, on both Claude and Codex.

• Default runs Claude at medium, and Codex at high on its most thorough model. A review of a small change from its diff alone can run one level lower.
• Low, Medium, High, Extra high and Max set the level for every run.

Each run shows the effort it used beside its model.

#AI spend

AI spend limits the runs Limn starts by itself, so they use only a share of your week. It is on by default at 50% of the week on a subscription. Your own runs are never limited. The full explanation is on AI subscription usage and spend.

#Disk space

Limn keeps one copy of each repository an AI run has read, and checks a pull request out for each run. A run removes its checkout when it ends. Disk space shows how much space this takes and how much Limn freed in the last 30 days.

A checkout left behind by a crash, or for a pull request that has merged or closed, is removed when Limn starts and when a new run begins. A checkout that holds a fix you have not pushed is kept until you push or discard it, for up to 14 days.