> ## 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.

# Arc MCP server

> Connect your AI coding tools to Arc documentation using the Model Context Protocol (MCP) server for search and full-page retrieval.

The Arc Model Context Protocol (MCP) server gives AI tools direct access to Arc
documentation so they can search for relevant content and retrieve full pages
during conversations. It is hosted at `https://docs.arc.io/mcp` and requires no
authentication.

The server exposes two tools:

* **Search**: finds relevant documentation snippets based on a query.
* **Get page**: retrieves the full content of a specific documentation page.

<Tip>
  For a machine-readable index of all documentation pages, see the [`llms.txt`
  file](https://docs.arc.io/llms.txt).
</Tip>

## Claude Code

Run the following command to add the Arc MCP server:

```bash theme={null}
claude mcp add --transport http arc-docs https://docs.arc.io/mcp
```

Claude Code automatically discovers the server's tools on the next conversation.

## Claude Desktop

1. Open **Settings** and navigate to **Connectors**.
2. Select **Add custom connector**.
3. Enter `Arc Docs` as the name and `https://docs.arc.io/mcp` as the URL.
4. During a chat, use the attachments button to select the Arc Docs connector.

## Cursor

Add the following to your `mcp.json` file (accessible via **Cursor Settings >
MCP**):

```json theme={null}
{
  "mcpServers": {
    "arc-docs": {
      "url": "https://docs.arc.io/mcp"
    }
  }
}
```

## VS Code (Copilot)

Create or update `.vscode/mcp.json` in your project root:

```json theme={null}
{
  "servers": {
    "arc-docs": {
      "type": "http",
      "url": "https://docs.arc.io/mcp"
    }
  }
}
```

## Windsurf

Add the following to your Windsurf MCP configuration:

```json theme={null}
{
  "mcpServers": {
    "arc-docs": {
      "serverUrl": "https://docs.arc.io/mcp"
    }
  }
}
```

## Other MCP clients

Any MCP-compatible client can connect using the HTTP transport at
`https://docs.arc.io/mcp`. Most clients require only the server URL and
transport type (`http`). Refer to your client's documentation for the exact
configuration format.

## Verify the connection

After adding the server, confirm the connection by asking your AI tool a
question about Arc, such as "What smart contract standards does Arc support?"
The tool should return content sourced from Arc documentation. If it does not:

* **Check the URL**: confirm it is exactly `https://docs.arc.io/mcp` with no
  trailing path.
* **Check network access**: the server must be reachable over HTTPS from your
  machine.
* **Restart the client**: some tools only detect new MCP servers after a restart
  or new session.