feat: Add code executor

core/src/main/java/com/google/adk/agents/LlmAgent.java

@@ -40,6 +40,7 @@
 import com.google.adk.agents.Callbacks.BeforeToolCallbackBase;
 import com.google.adk.agents.Callbacks.BeforeToolCallbackSync;
 import com.google.adk.agents.ConfigAgentUtils.ConfigurationException;
+import com.google.adk.codeexecutors.BaseCodeExecutor;
 import com.google.adk.events.Event;
 import com.google.adk.examples.BaseExampleProvider;
 import com.google.adk.examples.Example;
@@ -106,6 +107,7 @@ public enum IncludeContents {
   private final Optional<Schema> outputSchema;
   private final Optional<Executor> executor;
   private final Optional<String> outputKey;
+  private final Optional<BaseCodeExecutor> codeExecutor;
 
   private volatile Model resolvedModel;
   private final BaseLlmFlow llmFlow;
@@ -139,6 +141,7 @@ protected LlmAgent(Builder builder) {
     this.executor = Optional.ofNullable(builder.executor);
     this.outputKey = Optional.ofNullable(builder.outputKey);
     this.toolsUnion = builder.toolsUnion != null ? builder.toolsUnion : ImmutableList.of();
+    this.codeExecutor = Optional.ofNullable(builder.codeExecutor);
 
     this.llmFlow = determineLlmFlow();
 
@@ -179,6 +182,7 @@ public static class Builder {
     private Schema outputSchema;
     private Executor executor;
     private String outputKey;
+    private BaseCodeExecutor codeExecutor;
 
     @CanIgnoreReturnValue
     public Builder name(String name) {
@@ -563,6 +567,12 @@ public Builder outputKey(String outputKey) {
       return this;
     }
 
+    @CanIgnoreReturnValue
+    public Builder codeExecutor(BaseCodeExecutor codeExecutor) {
+      this.codeExecutor = codeExecutor;
+      return this;
+    }
+
     protected void validate() {
       this.disallowTransferToParent =
           this.disallowTransferToParent != null && this.disallowTransferToParent;
@@ -816,6 +826,11 @@ public Optional<String> outputKey() {
     return outputKey;
   }
 
+  @Nullable
+  public BaseCodeExecutor codeExecutor() {
+    return codeExecutor.orElse(null);
+  }
+
   public Model resolvedModel() {
     if (resolvedModel == null) {
       synchronized (this) {

core/src/main/java/com/google/adk/codeexecutors/BaseCodeExecutor.java

@@ -0,0 +1,88 @@
+/*
+ * Copyright 2025 Google LLC
+ *
+ * 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
+ *
+ *     http://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 com.google.adk.codeexecutors;
+
+import com.google.adk.JsonBaseModel;
+import com.google.adk.agents.InvocationContext;
+import com.google.adk.codeexecutors.CodeExecutionUtils.CodeExecutionInput;
+import com.google.adk.codeexecutors.CodeExecutionUtils.CodeExecutionResult;
+import com.google.common.collect.ImmutableList;
+import java.util.List;
+
+/**
+ * Abstract base class for all code executors.
+ *
+ * <p>The code executor allows the agent to execute code blocks from model responses and incorporate
+ * the execution results into the final response.
+ */
+public abstract class BaseCodeExecutor extends JsonBaseModel {
+  /**
+   * If true, extract and process data files from the model request and attach them to the code
+   * executor.
+   *
+   * <p>Supported data file MimeTypes are [text/csv]. Default to False.
+   */
+  public boolean optimizeDataFile() {
+    return false;
+  }
+
+  /** Whether the code executor is stateful. Default to False. */
+  public boolean stateful() {
+    return false;
+  }
+
+  /**
+   * The number of attempts to retry on consecutive code execution errors.
+   *
+   * <p>Default to 2.
+   */
+  public int errorRetryAttempts() {
+    return 2;
+  }
+
+  /**
+   * The list of the enclosing delimiters to identify the code blocks.
+   *
+   * <p>For example, the delimiter ('```python\n', '\n```') can be used to identify code blocks with
+   * the following format:
+   *
+   * <p>```python
+   *
+   * <p>print("hello")
+   *
+   * <p>```
+   */
+  public List<List<String>> codeBlockDelimiters() {
+    return ImmutableList.of(
+        ImmutableList.of("```tool_code\n", "\n```"), ImmutableList.of("```python\n", "\n```"));
+  }
+
+  /** The delimiters to format the code execution result. */
+  public List<String> executionResultDelimiters() {
+    return ImmutableList.of("```tool_output\n", "\n```");
+  }
+
+  /**
+   * Executes code and return the code execution result.
+   *
+   * @param invocationContext The invocation context of the code execution.
+   * @param codeExecutionInput The code execution input.
+   * @return The code execution result.
+   */
+  public abstract CodeExecutionResult executeCode(
+      InvocationContext invocationContext, CodeExecutionInput codeExecutionInput);
+}

core/src/main/java/com/google/adk/codeexecutors/BuiltInCodeExecutor.java

@@ -0,0 +1,60 @@
+/*
+ * Copyright 2025 Google LLC
+ *
+ * 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
+ *
+ *     http://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 com.google.adk.codeexecutors;
+
+import com.google.adk.agents.InvocationContext;
+import com.google.adk.codeexecutors.CodeExecutionUtils.CodeExecutionInput;
+import com.google.adk.codeexecutors.CodeExecutionUtils.CodeExecutionResult;
+import com.google.adk.models.LlmRequest;
+import com.google.adk.utils.ModelNameUtils;
+import com.google.common.collect.ImmutableList;
+import com.google.genai.types.GenerateContentConfig;
+import com.google.genai.types.Tool;
+import com.google.genai.types.ToolCodeExecution;
+
+/**
+ * A code executor that uses the Model's built-in code executor.
+ *
+ * <p>Currently only supports Gemini 2.0+ models, but will be expanded to other models.
+ */
+public class BuiltInCodeExecutor extends BaseCodeExecutor {
+
+  @Override
+  public CodeExecutionResult executeCode(
+      InvocationContext invocationContext, CodeExecutionInput codeExecutionInput) {
+    throw new UnsupportedOperationException(
+        "Code execution is not supported for built-in code executor.");
+  }
+
+  /** Pre-process the LLM request for Gemini 2.0+ models to use the code execution tool. */
+  public void processLlmRequest(LlmRequest.Builder llmRequestBuilder) {
+    LlmRequest llmRequest = llmRequestBuilder.build();
+    if (ModelNameUtils.isGemini2Model(llmRequest.model().orElse(null))) {
+      GenerateContentConfig.Builder configBuilder =
+          llmRequest.config().map(c -> c.toBuilder()).orElse(GenerateContentConfig.builder());
+      ImmutableList.Builder<Tool> toolsBuilder =
+          ImmutableList.<Tool>builder()
+              .addAll(configBuilder.build().tools().orElse(ImmutableList.<Tool>of()));
+      toolsBuilder.add(Tool.builder().codeExecution(ToolCodeExecution.builder().build()).build());
+      configBuilder.tools(toolsBuilder.build());
+      llmRequestBuilder.config(configBuilder.build());
+      return;
+    }
+    throw new IllegalArgumentException(
+        "Gemini code execution tool is not supported for model " + llmRequest.model().orElse(""));
+  }
+}