feat: disable apply_diff and enable edit tool for Vertex and Gemini providers

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

@@ -173,6 +173,20 @@ describe("GeminiHandler", () => {
 			const modelInfo = invalidHandler.getModel()
 			expect(modelInfo.id).toBe(geminiDefaultModelId) // Default model
 		})
+
+		it("should exclude apply_diff and include edit in tool preferences", () => {
+			const modelInfo = handler.getModel()
+			expect(modelInfo.info.excludedTools).toContain("apply_diff")
+			expect(modelInfo.info.includedTools).toContain("edit")
+		})
+
+		it("should not duplicate tool entries if already present", () => {
+			const modelInfo = handler.getModel()
+			const excludedCount = modelInfo.info.excludedTools!.filter((t: string) => t === "apply_diff").length
+			const includedCount = modelInfo.info.includedTools!.filter((t: string) => t === "edit").length
+			expect(excludedCount).toBe(1)
+			expect(includedCount).toBe(1)
+		})
 	})
 
 	describe("calculateCost", () => {

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

@@ -137,5 +137,31 @@ describe("VertexHandler", () => {
 			expect(modelInfo.info.maxTokens).toBe(8192)
 			expect(modelInfo.info.contextWindow).toBe(1048576)
 		})
+
+		it("should exclude apply_diff and include edit in tool preferences", () => {
+			const testHandler = new VertexHandler({
+				apiModelId: "gemini-2.0-flash-001",
+				vertexProjectId: "test-project",
+				vertexRegion: "us-central1",
+			})
+
+			const modelInfo = testHandler.getModel()
+			expect(modelInfo.info.excludedTools).toContain("apply_diff")
+			expect(modelInfo.info.includedTools).toContain("edit")
+		})
+
+		it("should not duplicate tool entries if already present", () => {
+			const testHandler = new VertexHandler({
+				apiModelId: "gemini-2.0-flash-001",
+				vertexProjectId: "test-project",
+				vertexRegion: "us-central1",
+			})
+
+			const modelInfo = testHandler.getModel()
+			const excludedCount = modelInfo.info.excludedTools!.filter((t: string) => t === "apply_diff").length
+			const includedCount = modelInfo.info.includedTools!.filter((t: string) => t === "edit").length
+			expect(excludedCount).toBe(1)
+			expect(includedCount).toBe(1)
+		})
 	})
 })

src/api/providers/gemini.ts

@@ -359,6 +359,13 @@ export class GeminiHandler extends BaseProvider implements SingleCompletionHandl
 			defaultTemperature: info.defaultTemperature ?? 1,
 		})
 
+		// Gemini models perform better with the edit tool instead of apply_diff.
+		info = {
+			...info,
+			excludedTools: [...new Set([...(info.excludedTools || []), "apply_diff"])],
+			includedTools: [...new Set([...(info.includedTools || []), "edit"])],
+		}
+
 		// The `:thinking` suffix indicates that the model is a "Hybrid"
 		// reasoning model and that reasoning is required to be enabled.
 		// The actual model ID honored by Gemini's API does not have this

src/api/providers/vertex.ts

@@ -15,7 +15,7 @@ export class VertexHandler extends GeminiHandler implements SingleCompletionHand
 	override getModel() {
 		const modelId = this.options.apiModelId
 		let id = modelId && modelId in vertexModels ? (modelId as VertexModelId) : vertexDefaultModelId
-		const info: ModelInfo = vertexModels[id]
+		let info: ModelInfo = vertexModels[id]
 		const params = getModelParams({
 			format: "gemini",
 			modelId: id,
@@ -24,6 +24,13 @@ export class VertexHandler extends GeminiHandler implements SingleCompletionHand
 			defaultTemperature: info.defaultTemperature ?? 1,
 		})
 
+		// Vertex Gemini models perform better with the edit tool instead of apply_diff.
+		info = {
+			...info,
+			excludedTools: [...new Set([...(info.excludedTools || []), "apply_diff"])],
+			includedTools: [...new Set([...(info.includedTools || []), "edit"])],
+		}
+
 		// The `:thinking` suffix indicates that the model is a "Hybrid"
 		// reasoning model and that reasoning is required to be enabled.
 		// The actual model ID honored by Gemini's API does not have this