fix(litellm): detect Gemini models with space-separated names for thought signature injection (#10787)

Author: daniel-lxs

src/api/providers/__tests__/lite-llm.spec.ts

@@ -414,13 +414,28 @@ describe("LiteLLMHandler", () => {
 				expect(isGeminiModel("gemini-2.5-flash")).toBe(true)
 			})
 
+			it("should detect Gemini models with spaces (LiteLLM model groups)", () => {
+				const handler = new LiteLLMHandler(mockOptions)
+				const isGeminiModel = (handler as any).isGeminiModel.bind(handler)
+
+				// LiteLLM model groups often use space-separated names with title case
+				expect(isGeminiModel("Gemini 3 Pro")).toBe(true)
+				expect(isGeminiModel("Gemini 3 Flash")).toBe(true)
+				expect(isGeminiModel("gemini 3 pro")).toBe(true)
+				expect(isGeminiModel("Gemini 2.5 Pro")).toBe(true)
+				expect(isGeminiModel("gemini 2.5 flash")).toBe(true)
+			})
+
 			it("should detect provider-prefixed Gemini models", () => {
 				const handler = new LiteLLMHandler(mockOptions)
 				const isGeminiModel = (handler as any).isGeminiModel.bind(handler)
 
 				expect(isGeminiModel("google/gemini-3-pro")).toBe(true)
 				expect(isGeminiModel("vertex_ai/gemini-3-pro")).toBe(true)
 				expect(isGeminiModel("vertex/gemini-2.5-pro")).toBe(true)
+				// Space-separated variants with provider prefix
+				expect(isGeminiModel("google/gemini 3 pro")).toBe(true)
+				expect(isGeminiModel("vertex_ai/gemini 2.5 pro")).toBe(true)
 			})
 
 			it("should not detect non-Gemini models", () => {

src/api/providers/lite-llm.ts

@@ -46,15 +46,21 @@ export class LiteLLMHandler extends RouterProvider implements SingleCompletionHa
 	private isGeminiModel(modelId: string): boolean {
 		// Match various Gemini model patterns:
 		// - gemini-3-pro, gemini-3-flash, gemini-3-*
+		// - gemini 3 pro, Gemini 3 Pro (space-separated, case-insensitive)
 		// - gemini/gemini-3-*, google/gemini-3-*
 		// - vertex_ai/gemini-3-*, vertex/gemini-3-*
 		// Also match Gemini 2.5+ models which use similar validation
 		const lowerModelId = modelId.toLowerCase()
 		return (
+			// Match hyphenated versions: gemini-3, gemini-2.5
 			lowerModelId.includes("gemini-3") ||
 			lowerModelId.includes("gemini-2.5") ||
+			// Match space-separated versions: "gemini 3", "gemini 2.5"
+			// This handles model names like "Gemini 3 Pro" from LiteLLM model groups
+			lowerModelId.includes("gemini 3") ||
+			lowerModelId.includes("gemini 2.5") ||
 			// Also match provider-prefixed versions
-			/\b(gemini|google|vertex_ai|vertex)\/gemini-(3|2\.5)/i.test(modelId)
+			/\b(gemini|google|vertex_ai|vertex)\/gemini[-\s](3|2\.5)/i.test(modelId)
 		)
 	}