New Relic MCP Server

Instructions

Implementation Reference

• src/tools/rest/metrics.ts:61-84 (handler)

  The core handler function `listMetricNames` in `RestMetricsTool` class that performs the API call to list metric names for a given application host using New Relic REST API v2, with optional pagination support.

  async listMetricNames(args: ListMetricNamesArgs): Promise<unknown> {
    const client = this.restFor(args.region);
    const path = `/applications/${args.application_id}/hosts/${args.host_id}/metrics`;
    const query: Record<string, unknown> = {};
    if (args.name) query.name = args.name;
    if (args.page) query.page = args.page;
    const results: unknown[] = [];
    let nextUrl: string | undefined;
    let page = args.page;
    do {
      const res = await client.get<unknown>(path, page ? { ...query, page } : query);
      results.push(res.data);
      const next = res.links?.next;
      if (args.auto_paginate && next) {
        const u = new URL(next);
        const p = u.searchParams.get('page');
        page = p ? Number(p) : undefined;
        nextUrl = next;
      } else {
        nextUrl = undefined;
      }
    } while (args.auto_paginate && nextUrl);
    return { items: args.auto_paginate ? results : results[0], page };
  }

• src/tools/rest/metrics.ts:42-59 (schema)

  The `getListMetricNamesTool` method defining the tool's metadata, description, and input schema for validation.

  getListMetricNamesTool(): Tool {
    return {
      name: 'list_metric_names_for_host',
      description: 'List metric names and values for a specific application host (REST v2).',
      inputSchema: {
        type: 'object',
        properties: {
          application_id: { type: 'number' },
          host_id: { type: 'number' },
          name: { type: 'string' },
          page: { type: 'number' },
          auto_paginate: { type: 'boolean' },
          region: { type: 'string', enum: ['US', 'EU'] },
        },
        required: ['application_id', 'host_id'],
      },
    };
  }

• src/server.ts:65-87 (registration)

  Registration of RestMetricsTool instance and addition of its tool definitions, including 'list_metric_names_for_host', to the server's tools registry for discovery.

  const restApm = new RestApmTool();
  const restMetrics = new RestMetricsTool();
  
  // Register all tools
  const tools = [
    nrqlTool.getToolDefinition(),
    apmTool.getListApplicationsTool(),
    entityTool.getSearchTool(),
    entityTool.getDetailsTool(),
    alertTool.getPoliciesTool(),
    alertTool.getIncidentsTool(),
    alertTool.getAcknowledgeTool(),
    syntheticsTool.getListMonitorsTool(),
    syntheticsTool.getCreateMonitorTool(),
    nerdGraphTool.getQueryTool(),
    // REST v2 tools
    restDeployments.getCreateTool(),
    restDeployments.getListTool(),
    restDeployments.getDeleteTool(),
    restApm.getListApplicationsTool(),
    restMetrics.getListMetricNamesTool(),
    restMetrics.getMetricDataTool(),
    restMetrics.getListApplicationHostsTool(),

• src/server.ts:191-194 (registration)

  Switch case in server's `executeTool` method that dispatches tool calls to the handler by instantiating RestMetricsTool and calling `listMetricNames`.

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