Telemetry

Codex exports traces and logs natively. It is configured entirely from its config.toml and reads no OTEL_* environment variable. It accepts no inbound trace context, so its spans form their own trace, correlated to the run by resource attribute.

Everything here is gated on the deployment exporting telemetry. See Observability for the OTEL_EXPORTER_OTLP_ENDPOINT master switch.

Exported signals

Signal	Exported	Notes
Traces	Yes
Logs	Yes	Codex calls these “events”.
Metrics	Configured	codex exec, the invocation a run uses, emits no metrics even with the exporter set. The exporter is still written explicitly.

Configuration

A run writes ~/.codex/config.toml, alongside the auth.json that subscription authentication uses:

# `<url>` is the collector base URL, e.g. http://collector:4318.
[otel]
environment = "local"
log_user_prompt = false
exporter = { otlp-http = { endpoint = "<url>/v1/logs", protocol = "binary" } }
trace_exporter = { otlp-http = { endpoint = "<url>/v1/traces", protocol = "binary" } }
metrics_exporter = { otlp-http = { endpoint = "<url>/v1/metrics", protocol = "binary" } }

Two things differ from the OpenTelemetry conventions used elsewhere. Each exporter takes the complete /v1/<signal> endpoint rather than a base URL, and the protocol is spelled binary or json rather than http/protobuf or http/json. A run maps the deployment’s protocol onto Codex’s spelling.

environment is taken from TCAB_ENV, matching the deployment.environment.name the rest of the system reports under. log_user_prompt is left at its default false, which keeps a run’s prompt out of telemetry.

metrics_exporter must be written explicitly. Its default is statsig, which ships a run’s metrics to that vendor rather than to the configured collector.

Trace linking

Codex starts a fresh trace for its spans. Every exporting harness carries the tcab.run_id, tcab.harness, tcab.test_case, tcab.variant, and tcab.model resource attributes, so the Codex trace for a run is found by querying those attributes or by correlating timestamps against the run’s own spans.