Heartbeat automations ignore custom provider/base_url and call api.openai.com

What happened?

Codex Desktop heartbeat automations appear to ignore the user's configured custom model provider / base URL and instead send requests to the official OpenAI endpoint.

In the same local Codex Desktop session, normal chat requests use the configured custom provider successfully:

POST https://custom-provider.example/v1/responses
model=openai/gpt-5.5
status=200

But a heartbeat automation triggered from the app uses the official OpenAI endpoint instead:

POST https://api.openai.com/v1/responses
model=gpt-5.5
status=401 Unauthorized
error=Incorrect API key provided

The key detail is that the heartbeat automation request is not using the configured custom provider endpoint, while normal chat requests do.

Config shape

Relevant ~/.codex/config.toml shape, with secrets omitted:

model_provider = "custom"
model = "openai/gpt-5.5"
disable_response_storage = true
model_reasoning_effort = "xhigh"

[model_providers.custom]
name = "custom"
wire_api = "responses"
requires_openai_auth = true
base_url = "https://custom-provider.example/v1"

Automation shape

The failing automation is a thread heartbeat automation:

kind = "heartbeat"
name = "Daily AI briefing"
status = "ACTIVE"
rrule = "RRULE:FREQ=WEEKLY;BYHOUR=22;BYMINUTE=0;BYDAY=SU,MO,TU,WE,TH,FR,SA"
target_thread_id = "..."

For comparison, a local cron automation can specify local execution fields, for example:

kind = "cron"
model = "openai/gpt-5.5"
execution_environment = "local"
cwds = ["/path/to/workspace"]

Expected behavior

Heartbeat automations should either:

1. inherit the same configured model_provider, model, wire_api, and base_url as normal Codex Desktop chat sessions; or
2. expose fields to explicitly configure provider/base URL/model for the heartbeat automation; or
3. fail early with a clear message that heartbeat automations only support official OpenAI-hosted execution and do not support custom providers.

Actual behavior

Heartbeat automation requests go to https://api.openai.com/v1/responses with model=gpt-5.5, even though normal chat requests in the same app/session go to the configured custom provider endpoint with model=openai/gpt-5.5.

Why this matters

Users who use OpenAI-compatible proxies/routers/custom providers can chat normally in Codex Desktop but cannot rely on heartbeat automations, because those automations silently use a different provider path and fail with auth errors.

Version / environment

• Codex CLI: 0.130.0
• Codex Desktop app logs show: app.version=0.131.0-alpha.9
• Wire API: Responses
• OS: macOS

Notes

All API keys and sensitive values were omitted or redacted.