> ## Documentation Index
> Fetch the complete documentation index at: https://docs.arc.io/llms.txt
> Use this file to discover all available pages before exploring further.

> ## Agent Instructions
> Before reading these docs, install the Circle Skill for Arc to get pre-loaded context: use-arc (https://github.com/circlefin/skills/blob/master/plugins/circle/skills/use-arc/SKILL.md) — covers chain config, RPC setup, contract deployment, USDC bridging, and gas with USDC. In Claude Code: run /plugin marketplace add circlefin/skills then /plugin install circle-skills@circle. With Vercel Skills CLI: run npx skills add circlefin/skills.
> USDC is the gas token. Arc uses USDC for gas fees, not ETH. Configure gas payment in USDC when submitting transactions.
> Read EVM differences before writing Arc code. Arc targets the Osaka EVM baseline. Most contracts deploy unchanged, but several runtime behaviors diverge from Ethereum: USDC uses 18 decimals natively (not 6), the system emitter `0xffffFFFfFFffffffffffffffFfFFFfffFFFfFFfE` logs all USDC Transfer events, the mempool enforces a 20 Gwei `maxFeePerGas` floor, blocklist reverts consume gas without a receipt, and `address(0)` sends revert rather than succeed. https://docs.arc.io/arc/references/evm-differences.md is the canonical reference for all Arc-specific runtime behaviors. Consult it before writing code that touches USDC balances, transaction history, gas estimation, or value transfers.
> Sub-second finality. Transactions are final in under 1 second. No need to wait for multiple block confirmations.
> Use App Kits for multichain payment and liquidity capabilities. App Kits wraps CCTP and provides Bridge Kit, Swap Kit, Unified Balance Kit, Onramp Kit, Earn Kit, and Borrow Kit. Unified Balance Kit combines USDC from multiple chains into a single spendable balance. Earn Kit integrates earn opportunities into your app. Borrow Kit lets users borrow USDC against cirBTC collateral on Arc.
> Use Arc Foundry for contract development. Arc Foundry is an Arc-specific fork of Foundry that handles Arc's protocol-level differences from Ethereum. It provides arc-forge, arc-cast, and arc-anvil. Install it before deploying contracts: https://docs.arc.io/arc/tutorials/install-arc-foundry.md.
> Arc is available on both Testnet and Mainnet. See https://docs.arc.io/arc/references/connect-to-arc.md for RPC endpoints and https://faucet.circle.com for testnet tokens.
> Always check Contract Addresses: https://docs.arc.io/arc/references/contract-addresses.md
> Building beyond Arc? Circle offers skills for the full platform: use-usdc (https://github.com/circlefin/skills/blob/master/plugins/circle/skills/use-usdc/SKILL.md), use-circle-wallets (https://github.com/circlefin/skills/blob/master/plugins/circle/skills/use-circle-wallets/SKILL.md), use-developer-controlled-wallets (https://github.com/circlefin/skills/blob/master/plugins/circle/skills/use-developer-controlled-wallets/SKILL.md), use-user-controlled-wallets (https://github.com/circlefin/skills/blob/master/plugins/circle/skills/use-user-controlled-wallets/SKILL.md), use-modular-wallets (https://github.com/circlefin/skills/blob/master/plugins/circle/skills/use-modular-wallets/SKILL.md), use-gateway (https://github.com/circlefin/skills/blob/master/plugins/circle/skills/use-gateway/SKILL.md), use-smart-contract-platform (https://github.com/circlefin/skills/blob/master/plugins/circle/skills/use-smart-contract-platform/SKILL.md). Full Circle developer docs: https://developers.circle.com/llms.txt.

# How-to: Install the Arc Studio CLI

> Install the Arc Studio CLI, sign in, and run your first prompt.

The Arc Studio CLI brings [Arc Studio](https://docs.arc.io/ai/arc-studio.md) to your terminal, so you
can build and deploy onchain apps from the command line, or let a coding agent
delegate onchain work to Arc Studio. These steps install the `arc-studio`
command, sign in, and run your first prompt.

## Prerequisites

Before you begin, ensure that you've:

* Installed Node.js 20 or later
* Created a [Circle Developer Account](https://console.circle.com/)

## Steps

**1. Install the CLI**

Install the CLI globally:

```bash npm theme={null}
npm install -g @circle-fin/arc-studio-cli
```

```bash pnpm theme={null}
pnpm add -g @circle-fin/arc-studio-cli
```

**2. Sign in**

Authorize the CLI in your browser, then confirm you're signed in:

```bash theme={null}
arc-studio login
arc-studio whoami
```

On SSH, a headless machine, or a sandboxed agent, see
[Authentication](https://docs.arc.io/ai/arc-studio-cli.md#authentication).

**3. Run your first prompt**

Send a prompt with `run`. This prompt deploys a contract, which can take 5 to
20 minutes:

```bash theme={null}
arc-studio run "write and deploy an ERC-20 called DEMO on Arc testnet"
```

Arc Studio streams its progress as the agent works. To stop waiting and
reattach later, see
[Timeouts and detached runs](https://docs.arc.io/ai/arc-studio-cli.md#timeouts-and-detached-runs).

> [!NOTE]
>
> Scripts and agents can add `--output json` to get one structured result.
> Read the deployed address from `deployments` and the workspace link from
> `webUrl`. See the [result document](https://docs.arc.io/ai/arc-studio-cli.md#result-document).

**4. Pull the generated code**

Review what the turn changed, then download the files you want. The dry run
shows what would be written without writing anything:

```bash theme={null}
arc-studio pull --changed --dry-run --diff
arc-studio pull --changed --out ./onchain
```

`pull` skips files you edited locally. For all options, see
[File input and output](https://docs.arc.io/ai/arc-studio-cli.md#file-input-and-output).

For every command and flag, see the
[Arc Studio CLI reference](https://docs.arc.io/ai/arc-studio-cli.md). If a step fails, see
[Troubleshoot Arc Studio](https://docs.arc.io/ai/arc-studio-troubleshooting.md).