Arbitrum MCP Server

Instructions

Implementation Reference

• src/clients/nitro-node-client.ts:156-170 (handler)

  Core handler function implementing the arb_checkPublisherHealth RPC call to check transaction publisher/sequencer health status. Returns healthy status or error if unsupported.

  async checkPublisherHealth(): Promise<PublisherHealth> {
    try {
      await this.makeRpcCall("arb_checkPublisherHealth", []);
      return {
        healthy: true,
      };
    } catch (error) {
      return {
        healthy: false,
        error: `Publisher health check failed or not supported on this RPC endpoint: ${
          (error as Error).message
        }`,
      };
    }
  }

• src/index.ts:412-426 (handler)

  MCP CallTool handler case that resolves the RPC URL using chain name or direct URL, creates NitroNodeClient instance, calls checkPublisherHealth(), and formats response as MCP content.

  case "arb_check_publisher_health": {
    const rpcUrl = await this.resolveRpcUrl(
      (args.rpcUrl as string) || (args.chainName as string)
    );
    const nodeClient = new NitroNodeClient(rpcUrl);
    const health = await nodeClient.checkPublisherHealth();
    return {
      content: [
        {
          type: "text",
          text: JSON.stringify(health, null, 2),
        },
      ],
    };
  }

• src/index.ts:1098-1118 (registration)

  Tool registration entry returned by ListTools handler, including name, description, and input schema for rpcUrl or chainName parameters.

  {
    name: "arb_check_publisher_health",
    description:
      "Check the health status of the transaction publisher/sequencer (requires admin API)",
    inputSchema: {
      type: "object" as const,
      properties: {
        rpcUrl: {
          type: "string",
          description:
            "The RPC URL of the Arbitrum node (optional if default is set)",
        },
        chainName: {
          type: "string",
          description:
            "Chain name (e.g., 'Xai', 'Arbitrum One') - will auto-resolve to RPC URL",
        },
      },
      required: [],
    },
  },

• src/clients/nitro-node-client.ts:55-58 (schema)

  TypeScript interface defining the output structure of the publisher health check response.

  export interface PublisherHealth {
    healthy: boolean;
    error?: string;
  }