fix(openai): omit temperature when no custom value is set (#242)

[proyectoauraorg]

Summary

When "use custom temperature" is off, the OpenAI-Compatible provider still sent temperature: 0 (the fallback), so the model's server-side default never applied. Per the discussion on #242 (option A, which @edelauna preferred), this omits the temperature field in that case.

Behavior

temperature is now included only when either the user set a custom temperature or the model needs a specific default (e.g. deepseek-reasoner); otherwise it is omitted.

• Preserves the supportsTemperature capability gate from fix(openai): omit temperature for models that don't support it (#215) #233 (still omitted when supportsTemperature === false).
• Preserves model-required defaults (deepseek-reasoner → DEEP_SEEK_DEFAULT_TEMPERATURE).
• A deliberately-set 0 is distinguished from "unset" and is still sent.
• Behavioral note: OpenAI-Compatible users who never set a temperature now get the model's server-side default instead of 0.

Scope

Targets the OpenAI-Compatible provider (the case reported in #242). The same ?? <default> pattern exists in the shared getModelParams and a few other providers (lite-llm, openai-native, lm-studio, vercel-ai-gateway, …); happy to converge them on this behavior in a follow-up — poe and moonshot already omit, so there is precedent.

Tests

api/providers/__tests__/openai.spec.ts: omitted by default, custom value sent, deliberate 0 sent, deepseek-reasoner default preserved, supportsTemperature === false still omitted. 53 pass.

Refs #242

Summary by CodeRabbit

Release Notes

• Bug Fixes
  • Improved temperature parameter handling for OpenAI-compatible providers. The temperature field is now omitted when no custom value is set, allowing server-side defaults to apply instead of forcing a value of 0. Explicit temperature values and model-specific defaults remain preserved.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

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📥 Commits

Reviewing files that changed from the base of the PR and between 45b239c and 5bb3ac8.

📒 Files selected for processing (3)

• .changeset/omit-temperature-when-unset.md
• src/api/providers/__tests__/openai.spec.ts
• src/api/providers/openai.ts

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📝 Walkthrough

Walkthrough

This PR modifies the OpenAI-compatible provider to omit the temperature parameter when not explicitly set, allowing server-side defaults to apply instead of forcing 0. The implementation preserves model-required defaults and explicit 0 values, tests are updated to validate the new behavior, and a changeset documents the change.

Changes

Temperature Omission for OpenAI-Compatible Provider

Layer / File(s)	Summary
Temperature parameter omission logic src/api/providers/openai.ts	OpenAiHandler.createMessage now conditionally includes temperature only when supported and either explicitly set or required for DeepSeek; otherwise omits the field to allow server defaults.
Test coverage for omission and explicit values src/api/providers/__tests__/openai.spec.ts	Test cases verify temperature is absent when no custom value is configured, explicitly set 0 is still transmitted, and Azure AI Service expectations reflect the omission of default temperature.
Changeset documentation .changeset/omit-temperature-when-unset.md	Changeset entry documents the provider behavior change to omit temperature when unset while preserving capability gating and explicit values.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~12 minutes

Possibly related PRs

• Zoo-Code-Org/Zoo-Code#233: Both PRs modify OpenAiHandler.createMessage temperature payload construction for the streaming request path.

Suggested reviewers

• taltas
• JamesRobert20
• navedmerchant
• hannesrudolph
• edelauna

Poem

🐰 A whisper of warmth, now softly withdrawn,
Let servers decide what defaults are drawn,
Unless you command, or DeepSeek must play,
Temperature's unset shall have its own way!

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Description check	⚠️ Warning	The PR description is missing the required 'Related GitHub Issue' section and 'Test Procedure' section from the template, though it provides detailed explanation of changes and behavior.	Add the 'Related GitHub Issue' section (Closes: #242) and 'Test Procedure' section explaining how to verify the fix and test results.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title accurately describes the main change: omitting the temperature field when no custom value is set in the OpenAI provider, which is the core fix in this PR.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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src/api/providers/__tests__/openai.spec.ts

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src/api/providers/openai.ts

ESLint skipped: the ESLint configuration for this file references a package that is not available in the sandbox.

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

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[edelauna]

Thanks for addressing this, just had some nits around documentation and comments.

[edelauna]

😅 i haven't been too strict about including changesets, can provide some rationale for providing this as part of this PR? I've kind of been thinking we'll update this as part of our release process, since it requires localization.

[edelauna]

I think it's ok not to document the specific issue in code, it'll be handled in commit history.