[BUG] OTEL_RESOURCE_ATTRIBUTES not applied to metrics, only works for events

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

The OTEL_RESOURCE_ATTRIBUTES environment variable is not being applied to metrics export. Resource attributes appear correctly in events under resource.attributes, but are completely missing from metrics dataPoints.attributes.

According to the OpenTelemetry specification, resource attributes should be attached to all telemetry signals (events, metrics, and traces), but Claude Code currently only applies them to events.

What Should Happen?

When OTEL_RESOURCE_ATTRIBUTES="user.name=test_user" is set in ~/.claude/settings.json, the attribute should appear in:

• ✅ Events: resource.attributes
• ✅ Metrics: Should be available in metric resource attributes

Error Messages/Logs

Example of event telemetry:

{
  resource: {
    attributes: {
      'user.name': 'test_user',
      'host.arch': 'arm64',
      'os.type': 'darwin',
      'os.version': '24.6.0',
      'service.name': 'claude-code',
      'service.version': '2.0.76'
    }
  },
  instrumentationScope: {
    name: 'com.anthropic.claude_code.events',
    version: '2.0.76',
    schemaUrl: undefined
  },
  timestamp: 1767745198782000,
  traceId: undefined,
  spanId: undefined,
  traceFlags: undefined,
  severityText: undefined,
  severityNumber: undefined,
  body: 'claude_code.api_request',
  attributes: {
    'user.id': '<id>',
    'session.id': 'a55b3854-d623-41f1-a3eb-01b74684c363',
    'terminal.type': 'Apple_Terminal',
    'event.name': 'api_request',
    'event.timestamp': '2026-01-07T00:19:58.782Z',
    model: 'claude-sonnet-4-5-20250929',
    input_tokens: '6',
    output_tokens: '245',
    cache_read_tokens: '45092',
    cache_creation_tokens: '728',
    cost_usd: '0.0199506',
    duration_ms: '4958'
  }
}


Example of metrics telemetry:

{
  descriptor: {
    name: 'claude_code.cost.usage',
    type: 'COUNTER',
    description: 'Cost of the Claude Code session',
    unit: 'USD',
    valueType: 1,
    advice: {}
  },
  dataPointType: 3,
  dataPoints: [
    {
      attributes: {
        'user.id': '<user id>',
        'session.id': '1d7a8638-c5e9-40d8-baf6-7f6d77dde198',
        'terminal.type': 'Apple_Terminal',
        model: 'us.anthropic.claude-sonnet-4-5-20250929-v1:0'
      },
      startTime: [ 1767743754, 82000000 ],
      endTime: [ 1767743767, 106000000 ],
      value: 0.17903220000000003
    },
    {
      attributes: {
        'user.id': '<user id>',
        'session.id': '1d7a8638-c5e9-40d8-baf6-7f6d77dde198',
        'terminal.type': 'Apple_Terminal',
        model: 'us.anthropic.claude-3-5-haiku-20241022-v1:0'
      },
      startTime: [ 1767743754, 251000000 ],
      endTime: [ 1767743767, 106000000 ],
      value: 0.0046296
    }
  ]
}

Steps to Reproduce

1. Edit ~/.claude/settings.json:

  {
    "env": {
      "CLAUDE_CODE_ENABLE_TELEMETRY": "1",
      "OTEL_RESOURCE_ATTRIBUTES": "user.name=test_user",
      "OTEL_LOGS_EXPORTER": "otlp,console",
      "OTEL_EXPORTER_OTLP_LOGS_PROTOCOL": "http/protobuf",
      "OTEL_EXPORTER_OTLP_LOGS_ENDPOINT": "<some endpoint>",
      "OTEL_EXPORTER_OTLP_HEADERS": "<some header>",
      "OTEL_METRICS_EXPORTER": "otlp,console",
      "OTEL_EXPORTER_OTLP_METRICS_PROTOCOL": "http/protobuf",
      "OTEL_EXPORTER_OTLP_METRICS_ENDPOINT": "<some endpoint>"
    }
  }

1. Restart Claude Code
2. Observe console output for both events and metrics
3. Notice that user.name appears in events' resource.attributes but is missing from metrics' dataPoints.attributes

Claude Model

Sonnet (default)

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

2.0.76

Platform

AWS Bedrock

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

_No response_