New Relic MCP Server

Instructions

Implementation Reference

• src/tools/rest/metrics.ts:158-167 (handler)

  The handler function that executes the list_application_hosts tool by querying the New Relic REST API for application hosts.

  async listApplicationHosts(args: ListHostsArgs): Promise<unknown> {
    const client = this.restFor(args.region);
    const path = `/applications/${args.application_id}/hosts`;
    const query: Record<string, unknown> = {};
    if (args.filter_hostname) query['filter[hostname]'] = args.filter_hostname;
    if (args.filter_ids) query['filter[ids]'] = args.filter_ids;
    if (args.page) query.page = args.page;
    const res = await client.get<unknown>(path, query);
    return res;
  }

• src/tools/rest/metrics.ts:139-156 (schema)

  Tool definition including name, description, and input schema for list_application_hosts.

  getListApplicationHostsTool(): Tool {
    return {
      name: 'list_application_hosts',
      description: 'List hosts for an APM application (REST v2).',
      inputSchema: {
        type: 'object',
        properties: {
          application_id: { type: 'number' },
          filter_hostname: { type: 'string' },
          filter_ids: { type: 'string' },
          page: { type: 'number' },
          auto_paginate: { type: 'boolean' },
          region: { type: 'string', enum: ['US', 'EU'] },
        },
        required: ['application_id'],
      },
    };
  }

• src/tools/rest/metrics.ts:27-34 (schema)

  TypeScript type definition for the input parameters of the listApplicationHosts handler.

  type ListHostsArgs = {
    application_id: number;
    filter_hostname?: string;
    filter_ids?: string; // comma-separated
    page?: number;
    auto_paginate?: boolean;
    region?: Region;
  };

• src/server.ts:87-87 (registration)

  Adds the list_application_hosts tool to the server's list of available tools.

  restMetrics.getListApplicationHostsTool(),

• src/server.ts:199-202 (registration)

  Switch case in executeTool that dispatches calls to the listApplicationHosts handler.

  case 'list_application_hosts':
    return await new RestMetricsTool().listApplicationHosts(
      args as Parameters<RestMetricsTool['listApplicationHosts']>[0]
    );