fix(provider): skip Gemini schema sanitization for Copilot models#15313
fix(provider): skip Gemini schema sanitization for Copilot models#15313yangheng95 wants to merge 2 commits intoanomalyco:devfrom
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The `sanitizeGemini` transform in `ProviderTransform.schema()` is
designed for Google's native Gemini API, which rejects certain JSON
Schema constructs (integer enums, empty array items, properties on
non-object types, etc.).
However, GitHub Copilot proxies Gemini models through an
OpenAI-compatible endpoint. The Copilot API handles Gemini-specific
schema requirements internally. Applying `sanitizeGemini` to Copilot
Gemini models (matched via `api.id.includes("gemini")`) produces
schemas that confuse the Copilot API's translation layer, causing
the model to fall back to plain-text tool call descriptions instead
of structured `tool_calls` in the response.
This was not an issue before v1.1.49 because `sanitizeGemini` only
performed mild transforms (enum stringification, required filtering).
Two post-v1.1.49 commits added more aggressive operations:
- 3741516 (default array items type to "string")
- 3adeed8 (strip properties/required from non-object types)
These additional transforms break tool calling for Copilot Gemini
models while Copilot Claude/GPT models are unaffected (they don't
match the `includes("gemini")` condition).
Fix: exclude `github-copilot` provider from `sanitizeGemini`.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
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Pull request overview
This PR prevents Copilot-hosted “Gemini” models (e.g. gemini-3-* served via the github-copilot provider) from going through the client-side sanitizeGemini JSON Schema transformation, since Copilot’s API is OpenAI-compatible and already handles Gemini-specific schema quirks internally.
Changes:
- Update
ProviderTransform.schema()to applysanitizeGeminionly for Google/Gemini models when the provider is notgithub-copilot*. - Add clarifying inline comments explaining why Copilot is excluded.
💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.
| // Convert integer enums to string enums for Google/Gemini. | ||
| // Skip for Copilot models — they use OpenAI-compatible format and the | ||
| // Copilot API handles Gemini schema requirements internally. | ||
| if ( | ||
| (model.providerID === "google" || model.api.id.includes("gemini")) && | ||
| !model.providerID.includes("github-copilot") | ||
| ) { |
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New behavior (skipping sanitizeGemini for github-copilot* providers) isn’t covered by unit tests. Please add a ProviderTransform.schema test case where providerID is "github-copilot" (or "github-copilot-enterprise") and api.id includes "gemini", asserting that Gemini-specific sanitization (e.g., enum-to-string conversion or stripping properties/required) does NOT occur.
Verify that sanitizeGemini is NOT applied when providerID is "github-copilot" or "github-copilot-enterprise", even when api.id includes "gemini". Asserts that enum values stay as integers and properties/required are preserved on non-object types. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
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Issue for this PR
Closes #15315
Type of change
What does this PR do?
sanitizeGeminiinProviderTransform.schema()matches Copilot Gemini models viaapi.id.includes("gemini"), but these models use an OpenAI-compatible endpoint — the Copilot API handles Gemini schema conversion internally.Two post-v1.1.49 commits (#11952, #11888) added aggressive schema transforms (defaulting array item types, stripping properties from non-object types) that produce double-transformed schemas the Copilot translation layer can't handle, breaking tool calling.
Fix: add
!model.providerID.includes("github-copilot")to the condition so Copilot models receive standard JSON Schema.How did you verify your code works?
transform.test.tstests passsanitizeGeminiis skipped forgithub-copilotandgithub-copilot-enterpriseprovidersincludes("gemini"))Screenshots / recordings
N/A — not a UI change.
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