> ## Documentation Index
> Fetch the complete documentation index at: https://seilabs-pr-registry-docs.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Environment Variables

> Configure Sei MCP Server with environment variables for wallet access and custom RPC endpoints

The Sei MCP Server supports configuration through environment variables, which can be set in your MCP configuration JSON or passed directly to the Node.js command.

## Configuration Methods

<Tabs>
  <Tab title="JSON Configuration">
    Add environment variables to your MCP server configuration:

    ```json theme={null}
    {
      "mcpServers": {
        "sei": {
          "command": "npx",
          "args": ["-y", "@sei-js/mcp-server"],
          "env": {
            "WALLET_MODE": "private-key",
            "PRIVATE_KEY": "0x123...",
            "MAINNET_RPC_URL": "https://your-custom-rpc.com"
          }
        }
      }
    }
    ```
  </Tab>

  <Tab title="Command Line">
    Pass environment variables directly to the Node.js command:

    ```bash theme={null}
    # Streamable HTTP with custom path (recommended)
    SERVER_TRANSPORT=streamable-http SERVER_PORT=8080 SERVER_PATH=/api/mcp npx @sei-js/mcp-server

    # Or export them first
    export SERVER_TRANSPORT=streamable-http
    export SERVER_PORT=8080
    export SERVER_PATH=/mcp
    npx @sei-js/mcp-server
    ```

    For Claude CLI:

    ```bash theme={null}
    # Add server to Claude CLI
    claude mcp add sei-http npx @sei-js/mcp-server --env SERVER_TRANSPORT=streamable-http SERVER_PORT=8080

    # Start Claude
    claude
    ```
  </Tab>
</Tabs>

## Available Variables

### Wallet Configuration

#### `WALLET_MODE`

* **Type**: `string`
* **Default**: `"disabled"`
* **Description**: Controls wallet functionality and transaction capabilities
* **Options**:
  * `"disabled"` - Read-only mode, no transaction capabilities
  * `"private-key"` - Enable wallet tools using private key

#### `PRIVATE_KEY`

* **Type**: `string`
* **Default**: `-`
* **Description**: Private key for wallet operations (required when WALLET\_MODE="private-key")
* **Format**: 0x-prefixed hex string (64 characters after 0x)

<Warning>
  **Security Critical**: Never commit private keys to version control. Use a dedicated test wallet with minimal funds.
</Warning>

### Network Configuration

#### `MAINNET_RPC_URL`

* **Type**: `string`
* **Default**: `"https://evm-rpc.sei-apis.com"`
* **Description**: Custom RPC endpoint for Sei mainnet
* **Use Case**: Private RPC providers, local nodes, or custom endpoints

#### `TESTNET_RPC_URL`

* **Type**: `string`
* **Default**: `"https://evm-rpc-testnet.sei-apis.com"`
* **Description**: Custom RPC endpoint for Sei testnet (Atlantic-2)
* **Use Case**: Testing with custom infrastructure

#### `DEVNET_RPC_URL`

* **Type**: `string`
* **Default**: `"https://evm-rpc-arctic-1.sei-apis.com"`
* **Description**: Custom RPC endpoint for Sei devnet
* **Use Case**: Development and experimental features

### Server Configuration

#### `SERVER_TRANSPORT`

* **Type**: `string`
* **Default**: `"stdio"`
* **Description**: Transport mode for the MCP server
* **Options**:
  * `"stdio"` - Standard input/output (default for AI assistants)
  * `"streamable-http"` - Streamable HTTP transport (recommended for web apps)
  * `"http-sse"` - HTTP Server-Sent Events (deprecated)

#### `SERVER_PORT`

* **Type**: `number`
* **Default**: `8080`
* **Description**: Port number for HTTP transports (http-sse, streamable-http)
* **Range**: 1-65535

#### `SERVER_HOST`

* **Type**: `string`
* **Default**: `"localhost"`
* **Description**: Host address for HTTP server
* **Use Case**: Bind to specific network interfaces

#### `SERVER_PATH`

* **Type**: `string`
* **Default**: `"/mcp"`
* **Description**: Base path for HTTP endpoints
* **Format**: Must start with `/` (automatically normalized)

### System Configuration

#### `PATH`

* **Type**: `string`
* **Default**: System PATH
* **Description**: Override PATH to specify Node.js version
* **Use Case**: Troubleshooting Node.js version conflicts

## Configuration Examples

<AccordionGroup>
  <Accordion title="Default STDIO Mode">
    No environment variables needed for AI assistant integration:

    <Tabs>
      <Tab title="JSON Config">
        ```json theme={null}
        {
          "mcpServers": {
            "sei": {
              "command": "npx",
              "args": ["-y", "@sei-js/mcp-server"]
            }
          }
        }
        ```
      </Tab>

      <Tab title="CLI">
        ```bash theme={null}
        # Default STDIO mode (no environment variables needed)
        npx @sei-js/mcp-server

        # Or with Claude CLI
        claude mcp add sei npx @sei-js/mcp-server
        ```
      </Tab>
    </Tabs>

    **Transport**: Standard input/output for Claude Desktop, Cursor, Windsurf
  </Accordion>

  <Accordion title="Streamable HTTP Transport">
    Use streamable HTTP when you need API access over HTTP:

    <Tabs>
      <Tab title="JSON Config">
        ```json theme={null}
        {
          "mcpServers": {
            "sei": {
              "command": "npx",
              "args": ["-y", "@sei-js/mcp-server"],
              "env": {
                "SERVER_TRANSPORT": "streamable-http",
                "SERVER_PORT": "8080",
                "SERVER_PATH": "/api/mcp",
                "SERVER_HOST": "0.0.0.0"
              }
            }
          }
        }
        ```
      </Tab>

      <Tab title="CLI">
        ```bash theme={null}
        # Streamable HTTP with custom configuration
        SERVER_TRANSPORT=streamable-http \
        SERVER_PORT=8080 \
        SERVER_PATH=/api/mcp \
        SERVER_HOST=0.0.0.0 \
        npx @sei-js/mcp-server

        # Or with Claude CLI
        claude mcp add sei-http npx @sei-js/mcp-server \
          --env SERVER_TRANSPORT=streamable-http \
          --env SERVER_PORT=8080 \
          --env SERVER_PATH=/api/mcp
        ```
      </Tab>
    </Tabs>

    **Use Case**: Web applications, custom integrations, API access
  </Accordion>

  <Accordion title="HTTP SSE Transport (Deprecated)">
    HTTP Server-Sent Events transport - use streamable-http instead:

    <Tabs>
      <Tab title="JSON Config">
        ```json theme={null}
        {
          "mcpServers": {
            "sei": {
              "command": "npx",
              "args": ["-y", "@sei-js/mcp-server"],
              "env": {
                "SERVER_TRANSPORT": "http-sse",
                "SERVER_PORT": "3001",
                "SERVER_PATH": "/mcp"
              }
            }
          }
        }
        ```
      </Tab>

      <Tab title="CLI">
        ```bash theme={null}
        # HTTP SSE (deprecated - use streamable-http instead)
        SERVER_TRANSPORT=http-sse \
        SERVER_PORT=3001 \
        SERVER_PATH=/mcp \
        npx @sei-js/mcp-server

        # Or with Claude CLI
        claude mcp add sei-sse npx @sei-js/mcp-server \
          --env SERVER_TRANSPORT=http-sse \
          --env SERVER_PORT=3001
        ```
      </Tab>
    </Tabs>

    **Status**: Deprecated - migrate to streamable-http for better performance
  </Accordion>
</AccordionGroup>

## Security Best Practices

<CardGroup cols={2}>
  <Card title="Test Wallet Only" icon="shield-check">
    Use a dedicated wallet for testing, not your main holdings
  </Card>

  <Card title="Minimal Funds" icon="coins">
    Keep only small amounts needed for testing transactions
  </Card>

  <Card title="Secure Storage" icon="lock">
    Never commit private keys to version control or share them
  </Card>

  <Card title="Regular Rotation" icon="arrows-rotate">
    Rotate test wallet keys periodically for security
  </Card>
</CardGroup>

## Troubleshooting

### Common Issues

**Private Key Format**

* Must start with `0x`
* Must be exactly 66 characters (0x + 64 hex characters)
* Use lowercase hex characters

**RPC Connection**

* Verify custom RPC URLs are accessible
* Check for rate limiting on custom endpoints
* Ensure RPC supports required methods

**Environment Variables Not Loading**

* Restart your AI assistant after configuration changes
* Verify JSON syntax in MCP configuration
* Check for typos in variable names

<Card title="Need More Help?" icon="bug" href="/mcp-server/troubleshooting">
  Check our comprehensive troubleshooting guide for solutions to specific problems.
</Card>