Add a new interface InitToolCallbackResolverErrorHandler as extension for customized actions when ToolCallbackProvider.getToolCallbacks() fail on application starting up

auto-configurations/models/tool/spring-ai-autoconfigure-model-tool/src/main/java/org/springframework/ai/model/tool/autoconfigure/ToolCallingAutoConfiguration.java

@@ -32,6 +32,7 @@
 import org.springframework.ai.tool.observation.ToolCallingContentObservationFilter;
 import org.springframework.ai.tool.observation.ToolCallingObservationConvention;
 import org.springframework.ai.tool.resolution.DelegatingToolCallbackResolver;
+import org.springframework.ai.tool.resolution.InitToolCallbackResolverErrorHandler;
 import org.springframework.ai.tool.resolution.SpringBeanToolCallbackResolver;
 import org.springframework.ai.tool.resolution.StaticToolCallbackResolver;
 import org.springframework.ai.tool.resolution.ToolCallbackResolver;
@@ -63,10 +64,22 @@ public class ToolCallingAutoConfiguration {
 	@Bean
 	@ConditionalOnMissingBean
 	ToolCallbackResolver toolCallbackResolver(GenericApplicationContext applicationContext,
-			List<ToolCallback> toolCallbacks, List<ToolCallbackProvider> tcbProviders) {
+			List<ToolCallback> toolCallbacks, List<ToolCallbackProvider> tcbProviders,
+			List<InitToolCallbackResolverErrorHandler> errorHandlers) {
 
 		List<ToolCallback> allFunctionAndToolCallbacks = new ArrayList<>(toolCallbacks);
-		tcbProviders.stream().map(pr -> List.of(pr.getToolCallbacks())).forEach(allFunctionAndToolCallbacks::addAll);
+		for (ToolCallbackProvider pr : tcbProviders) {
+			try {
+				allFunctionAndToolCallbacks.addAll(List.of(pr.getToolCallbacks()));
+			}
+			catch (Throwable t) {
+				allFunctionAndToolCallbacks.addAll(errorHandlers.stream()
+					.filter(h -> h.support(pr, t))
+					.findFirst()
+					.orElseThrow(() -> new RuntimeException(t))
+					.handle(pr, t));
+			}
+		}
 
 		var staticToolCallbackResolver = new StaticToolCallbackResolver(allFunctionAndToolCallbacks);
 

auto-configurations/models/tool/spring-ai-autoconfigure-model-tool/src/test/java/org/springframework/ai/model/tool/autoconfigure/ToolCallingAutoConfigurationTests.java

@@ -16,6 +16,8 @@
 
 package org.springframework.ai.model.tool.autoconfigure;
 
+import java.util.Collections;
+import java.util.List;
 import java.util.function.Function;
 
 import org.junit.jupiter.api.Test;
@@ -35,13 +37,16 @@
 import org.springframework.ai.tool.method.MethodToolCallbackProvider;
 import org.springframework.ai.tool.observation.ToolCallingContentObservationFilter;
 import org.springframework.ai.tool.resolution.DelegatingToolCallbackResolver;
+import org.springframework.ai.tool.resolution.InitToolCallbackResolverErrorHandler;
 import org.springframework.ai.tool.resolution.ToolCallbackResolver;
 import org.springframework.ai.tool.support.ToolDefinitions;
 import org.springframework.boot.autoconfigure.AutoConfigurations;
 import org.springframework.boot.test.context.runner.ApplicationContextRunner;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.context.annotation.Description;
+import org.springframework.core.Ordered;
+import org.springframework.util.Assert;
 import org.springframework.util.ReflectionUtils;
 
 import static org.assertj.core.api.Assertions.assertThat;
@@ -185,6 +190,14 @@ void throwExceptionOnErrorEnabled() {
 			});
 	}
 
+	@Test
+	void testInitToolCallbackResolverErrorHandler() {
+		new ApplicationContextRunner().withConfiguration(AutoConfigurations.of(ToolCallingAutoConfiguration.class))
+			.withUserConfiguration(InitToolCallbackResolverErrorHandlerTestConf.class)
+			.run(context -> assertThat(context.getBeansOfType(InitToolCallbackResolverErrorHandler.class))
+				.isNotEmpty());
+	}
+
 	static class WeatherService {
 
 		@Tool(description = "Get the weather in location. Return temperature in 36°F or 36°C format.")
@@ -275,4 +288,39 @@ public record Response(String temperature) {
 
 	}
 
+	@Configuration
+	static class InitToolCallbackResolverErrorHandlerTestConf {
+
+		private static final String ERROR_MSG = "TestError";
+
+		@Bean
+		public ToolCallbackProvider errorToolCallbackProvider() {
+			return () -> {
+				throw new RuntimeException(ERROR_MSG);
+			};
+		}
+
+		@Bean
+		public InitToolCallbackResolverErrorHandler testErrorHandler() {
+			return new InitToolCallbackResolverErrorHandler() {
+				@Override
+				public boolean support(ToolCallbackProvider provider, Throwable t) {
+					return true;
+				}
+
+				@Override
+				public List<ToolCallback> handle(ToolCallbackProvider provider, Throwable t) {
+					Assert.isTrue(ERROR_MSG.equals(t.getMessage()), "error");
+					return Collections.emptyList();
+				}
+
+				@Override
+				public int getOrder() {
+					return Ordered.LOWEST_PRECEDENCE;
+				}
+			};
+		}
+
+	}
+
 }

spring-ai-model/src/main/java/org/springframework/ai/tool/resolution/InitToolCallbackResolverErrorHandler.java

@@ -0,0 +1,51 @@
+/*
+ * Copyright 2025-2025 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.ai.tool.resolution;
+
+import java.util.List;
+
+import org.springframework.ai.tool.ToolCallback;
+import org.springframework.ai.tool.ToolCallbackProvider;
+import org.springframework.core.Ordered;
+
+/**
+ * Handler for errors when {@link ToolCallbackResolver} failed to fetch ToolCallbacks on
+ * application starting up.
+ *
+ * @author walter.tan
+ * @since 1.0.2
+ */
+public interface InitToolCallbackResolverErrorHandler extends Ordered {
+
+	/**
+	 * Check whether the handler supports the given provider and error.
+	 * @param provider the failed ToolCallbackProvider
+	 * @param t the error caught
+	 * @return
+	 */
+	boolean support(ToolCallbackProvider provider, Throwable t);
+
+	/**
+	 * Handle errors when initializing the {@link ToolCallbackResolver} failed and return
+	 * fallback ToolCallbacks on demand.
+	 * @param provider the failed ToolCallbackProvider
+	 * @param t the error caught
+	 * @return
+	 */
+	List<ToolCallback> handle(ToolCallbackProvider provider, Throwable t);
+
+}