OpenAI rejects non-default temperature on gpt-5 / gpt-5-chat with
HTTP 400 ("Unsupported value: 'temperature' does not support 0.7
with this model. Only the default (1) value is supported.").
skipTemp in buildRequestBody only covered gpt-5-mini / gpt-5-nano and
the o-series, so base gpt-5 and gpt-5-chat fell through and received
config.DefaultTemperature (0.7). On channel integrations the inbound
error is suppressed, leaving the agent silently dead.
The gpt-5.X flagship variants (gpt-5.1, gpt-5.4, gpt-5.5) keep their
temperature — only the base gpt-5 and gpt-5-chat aliases are locked
to the default.
Regression cases added for gpt-5, gpt-5-chat, gpt-5-chat-latest and
provider-prefixed forms; gpt-5 moved to the locked list in
TestBuildRequestBody_TemperatureKeptForNonReasoningModels per the
maintainer triage on #1460.
Fixes#1460
fchengyan
0fef6ff596