Not able to use env var for otlp headers in config

What version of Codex CLI is running?

0.114.0

What subscription do you have?

Pro

Which model were you using?

GPT-5.4

What platform is your computer?

Arch Linux

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

Ghostty

What issue are you seeing?

I am able to set up and use OTEL config. But I want to pass shell environment variables to the header value. This example in the doc does not work now.

[otel]
exporter = { otlp-http = {
endpoint = "https://otel.example.com/v1/logs",
protocol = "binary",
headers = { "x-otlp-api-key" = "${OTLP_TOKEN}" }
}}

It works if I hardcode the token value.

What steps can reproduce the bug?

Try to use environment variable in OTEL config headers

What is the expected behavior?

OTEL config headers should be able to interpolate the value from shell environment variables

Additional information

_No response_