OTel response.completed reports total token usage as tool_token_count

What version of Codex CLI is running?

codex-cli 0.149.0-alpha.4.1

What subscription do you have?

ChatGPT Pro ($200/month)

Which model were you using?

gpt-5.6-sol

What platform is your computer?

Darwin 25.5.0 arm64 arm (macOS 26.5.2)

What terminal emulator and version are you using (if applicable)?

Not applicable (source-level issue)

Codex doctor report

Not run (source-level issue)

What issue are you seeing?

The response.completed OpenTelemetry event exports TokenUsage.total_tokens under the attribute tool_token_count:

tool_token_count = %usage.total_tokens

TokenUsage.total_tokens comes directly from the provider's response.completed.response.usage.total_tokens. It represents total token usage, not tool-specific token usage.

This is an OpenTelemetry attribute naming/semantic mismatch, not a token calculation error. Downstream consumers can interpret the same value as either total tokens or tool tokens.

What steps can reproduce the bug?

1. Inspect codex-rs/otel/src/events/session_telemetry.rs on current main.
2. Trace usage.total_tokens back to TokenUsage.total_tokens, populated from the provider's completed-response usage.
3. Observe that the value is emitted as tool_token_count.
4. See the existing OTel test expecting the same attribute.

Current source:

• Emission site
• Test expectation

What is the expected behavior?

The OpenTelemetry attribute name should match the value's semantics. Total usage should be exposed as a total-token attribute, or the historical field should be explicitly documented with a compatibility and migration plan.

Additional information

Related but not duplicate: #33668 reports a missing codex.turn.token_usage metric.

External consumers already handle this field inconsistently: Statewright maps it to total_tokens, while ax and ai-observer treat it as tool tokens.

The naming mismatch was introduced with #2103 and remains present on current main.

Start with codex-rs/otel/src/events/session_telemetry.rs at the response.completed emission and trace usage.total_tokens to its provider usage source. Then read codex-rs/core/tests/suite/otel.rs around the existing expectation. Confirm the intended compatibility approach for the attribute name, and update the emission and test or documentation so the value's semantics are unambiguous.