fix: exclude undefined max token fields from settings export

- Modified ProviderSettingsManager export method to exclude modelMaxTokens and modelMaxThinkingTokens when undefined
- Prevents these fields from appearing in exported settings for models that do not support reasoning budgets
- Added test to verify undefined fields are properly excluded from export

Fixes #7944

src/core/config/ProviderSettingsManager.ts

@@ -471,7 +471,21 @@ export class ProviderSettingsManager {
 				const configs = profiles.apiConfigs
 				for (const name in configs) {
 					// Avoid leaking properties from other providers.
-					configs[name] = discriminatedProviderSettingsWithIdSchema.parse(configs[name])
+					let config = discriminatedProviderSettingsWithIdSchema.parse(configs[name])
+
+					// Remove max token fields if they are undefined
+					// These fields should only be included for models that support reasoning budgets
+					// and when the user has explicitly set values
+					// Use type assertion to access these optional fields
+					const configAny = config as any
+					if (configAny.modelMaxTokens === undefined) {
+						delete configAny.modelMaxTokens
+					}
+					if (configAny.modelMaxThinkingTokens === undefined) {
+						delete configAny.modelMaxThinkingTokens
+					}
+
+					configs[name] = config
 				}
 				return profiles
 			})

src/core/config/__tests__/importExport.spec.ts

@@ -1608,5 +1608,76 @@ describe("importExport", () => {
 				"https://custom-api.example.com/v1",
 			)
 		})
+
+		it("should exclude undefined modelMaxTokens and modelMaxThinkingTokens from export", async () => {
+			// This test verifies that undefined max token fields are not included in the export
+			// to prevent them from appearing for models that don't support reasoning budgets
+
+			;(vscode.window.showSaveDialog as Mock).mockResolvedValue({
+				fsPath: "/mock/path/roo-code-settings.json",
+			})
+
+			const mockProviderProfiles = {
+				currentApiConfigName: "test-provider",
+				apiConfigs: {
+					"test-provider": {
+						apiProvider: "openai" as ProviderName,
+						id: "test-id",
+						// modelMaxTokens and modelMaxThinkingTokens are undefined
+						apiKey: "test-key",
+						openAiBaseUrl: "https://api.openai.com/v1",
+					},
+					"anthropic-provider": {
+						apiProvider: "anthropic" as ProviderName,
+						id: "anthropic-id",
+						apiKey: "anthropic-key",
+						modelMaxTokens: 4096, // This one has a value set
+						// modelMaxThinkingTokens is undefined
+					},
+					"reasoning-provider": {
+						apiProvider: "openrouter" as ProviderName,
+						id: "reasoning-id",
+						openRouterApiKey: "reasoning-key",
+						modelMaxTokens: 8192,
+						modelMaxThinkingTokens: 4096, // Both values set for reasoning model
+					},
+				},
+				modeApiConfigs: {},
+			}
+
+			const mockGlobalSettings = {
+				mode: "code",
+				autoApprovalEnabled: true,
+			}
+
+			mockProviderSettingsManager.export.mockResolvedValue(mockProviderProfiles)
+			mockContextProxy.export.mockResolvedValue(mockGlobalSettings)
+			;(fs.mkdir as Mock).mockResolvedValue(undefined)
+
+			await exportSettings({
+				providerSettingsManager: mockProviderSettingsManager,
+				contextProxy: mockContextProxy,
+			})
+
+			// Get the exported data
+			const exportedData = (safeWriteJson as Mock).mock.calls[0][1]
+
+			// Verify that undefined fields are not included in the export
+			const testProvider = exportedData.providerProfiles.apiConfigs["test-provider"]
+			expect(testProvider.apiKey).toBe("test-key")
+			expect(testProvider.openAiBaseUrl).toBe("https://api.openai.com/v1")
+			expect("modelMaxTokens" in testProvider).toBe(false) // Should not be present
+			expect("modelMaxThinkingTokens" in testProvider).toBe(false) // Should not be present
+
+			// Verify that defined modelMaxTokens is included but undefined modelMaxThinkingTokens is not
+			const anthropicProvider = exportedData.providerProfiles.apiConfigs["anthropic-provider"]
+			expect(anthropicProvider.modelMaxTokens).toBe(4096) // Should be present with value
+			expect("modelMaxThinkingTokens" in anthropicProvider).toBe(false) // Should not be present
+
+			// Verify that both fields are included when they have values
+			const reasoningProvider = exportedData.providerProfiles.apiConfigs["reasoning-provider"]
+			expect(reasoningProvider.modelMaxTokens).toBe(8192) // Should be present with value
+			expect(reasoningProvider.modelMaxThinkingTokens).toBe(4096) // Should be present with value
+		})
 	})
 })