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Observability for OpenAI Codex with Opik

OpenAI Codex supports opt-in OpenTelemetry export through Codex configuration files.

When this guide applies

Use this guide if you run Codex (CLI/IDE/app) and want its OTEL trace exporter to send telemetry to Opik.

The block structure below follows the current Codex runtime config shape used in local config.toml ([otel.trace_exporter.otlp-http]).

Where to configure Codex

Codex reads configuration from:

  • user config: ~/.codex/config.toml
  • project config: .codex/config.toml

See Codex config basics.

Opik OTLP trace endpoint modes

For Opik OTEL endpoint behavior, see Opik OpenTelemetry overview.

1[otel]
2# Optional environment label in Codex telemetry
3trace_exporter = "otlp-http"
4environment = "prod"
5log_user_prompt = false
6
7[otel.trace_exporter.otlp-http]
8endpoint = "https://www.comet.com/opik/api/v1/private/otel/v1/traces"
9protocol = "binary"
10headers = { "Authorization" = "<your-api-key>", "Comet-Workspace" = "<your-workspace>", "projectName" = "<your-project-name>" }

Required headers:

  • Authorization
  • Comet-Workspace

Optional headers:

  • projectName (recommended)

Example intent and minimal valid setup

Intent: Route Codex OTEL trace export to Opik with project/workspace attribution.

Applies when: You have enabled Codex OTEL export and selected OTLP/HTTP exporter in config.

Required fields:

  • trace_exporter = "otlp-http" under [otel]
  • otel.trace_exporter exporter block (otlp-http)
  • endpoint
  • protocol (binary or json, binary recommended)

Optional fields:

  • headers (projectName strongly recommended)
  • otel.environment
  • otel.log_user_prompt (keep false unless policy allows prompt export)

Minimal valid config:

1[otel]
2trace_exporter = "otlp-http"
3log_user_prompt = false
4
5[otel.trace_exporter.otlp-http]
6endpoint = "https://www.comet.com/opik/api/v1/private/otel/v1/traces"
7protocol = "binary"
8headers = { "Authorization" = "<your-api-key>", "Comet-Workspace" = "<your-workspace>", "projectName" = "<your-project-name>" }

Validation

  1. Run a Codex session after updating config.toml.
  2. Confirm OTLP HTTP requests are sent to /otel/v1/traces.
  3. Verify traces appear in the expected Opik workspace/project.

Notes

  • Codex telemetry export is opt-in.
  • Keep log_user_prompt = false unless your policy explicitly allows prompt text export.
  • If your Codex build uses a different exporter key path, align with your installed version’s config reference.

Source references