使用 LlmAgent 构建简单智能体¶

// 示例：定义基本身份
LlmAgent capitalAgent =
    LlmAgent.builder()
        .model("gemini-flash-latest")
        .name("capital_agent")
        .description("Answers user questions about the capital city of a given country.")
        // 指令和工具将在后面添加
        .build();

// 示例：添加指令
LlmAgent capitalAgent =
    LlmAgent.builder()
        .model("gemini-flash-latest")
        .name("capital_agent")
        .description("Answers user questions about the capital city of a given country.")
        .instruction(
            """
            You are an agent that provides the capital city of a country.
            When a user asks for the capital of a country:
            1. Identify the country name from the user's query.
            2. Use the `get_capital_city` tool to find the capital.
            3. Respond clearly to the user, stating the capital city.
            Example Query: "What's the capital of {country}?"
            Example Response: "The capital of France is Paris."
            """)
        // 工具将在后面添加
        .build();

// 定义工具函数
// 检索给定国家的首都城市。
public static Map<String, Object> getCapitalCity(
        @Schema(name = "country", description = "The country to get capital for")
        String country) {
  // 替换为实际逻辑（例如 API 调用、数据库查询）
  Map<String, String> countryCapitals = new HashMap<>();
  countryCapitals.put("canada", "Ottawa");
  countryCapitals.put("france", "Paris");
  countryCapitals.put("japan", "Tokyo");

  String result =
          countryCapitals.getOrDefault(
                  country.toLowerCase(), "Sorry, I couldn't find the capital for " + country + ".");
  return Map.of("result", result); // 工具必须返回一个 Map
}

// 将工具添加到智能体
FunctionTool capitalTool = FunctionTool.create(experiment.getClass(), "getCapitalCity");
LlmAgent capitalAgent =
    LlmAgent.builder()
        .model("gemini-flash-latest")
        .name("capital_agent")
        .description("Answers user questions about the capital city of a given country.")
        .instruction("You are an agent that provides the capital city of a country... (previous instruction text)")
        .tools(capitalTool) // 提供包装为 FunctionTool 的函数
        .build();

import com.google.genai.types.GenerateContentConfig;

LlmAgent agent =
    LlmAgent.builder()
        // ... 其他参数
        .generateContentConfig(GenerateContentConfig.builder()
            .temperature(0.2F) // 更确定性的输出
            .maxOutputTokens(250)
            .build())
        .build();

private static final Schema CAPITAL_OUTPUT =
    Schema.builder()
        .type("OBJECT")
        .description("Schema for capital city information.")
        .properties(
            Map.of(
                "capital",
                Schema.builder()
                    .type("STRING")
                    .description("The capital city of the country.")
                    .build()))
        .build();

LlmAgent structuredCapitalAgent =
    LlmAgent.builder()
        // ... 名称、模型、描述
        .instruction(
                "You are a Capital Information Agent. Given a country, respond ONLY with a JSON object containing the capital. Format: {\"capital\": \"capital_name\"}")
        .outputSchema(CAPITAL_OUTPUT) // 强制 JSON 输出
        .outputKey("found_capital") // 将结果存储在 state.get("found_capital") 中
        // 此处无法有效使用 tools(getCapitalCity)
        .build();

import com.google.adk.agents.LlmAgent.IncludeContents;

LlmAgent statelessAgent =
    LlmAgent.builder()
        // ... 其他参数
        .includeContents(IncludeContents.NONE)
        .build();

import com.google.adk.agents.BaseAgent;
import com.google.adk.agents.LlmAgent;
import com.google.adk.runner.Runner;
import com.google.adk.sessions.InMemorySessionService;
import com.google.adk.sessions.Session;
import com.google.adk.tools.BuiltInCodeExecutionTool;
import com.google.common.collect.ImmutableList;
import com.google.genai.types.Content;
import com.google.genai.types.Part;

public class CodeExecutionAgentApp {

  private static final String AGENT_NAME = "calculator_agent";
  private static final String APP_NAME = "calculator";
  private static final String USER_ID = "user1234";
  private static final String SESSION_ID = "session_code_exec_sync";
  private static final String GEMINI_MODEL = "gemini-2.0-flash";

  /**
   * Calls the agent with a query and prints the interaction events and final response.
   *
   * @param runner The runner instance for the agent.
   * @param query The query to send to the agent.
   */
  public static void callAgent(Runner runner, String query) {
    Content content =
        Content.builder().role("user").parts(ImmutableList.of(Part.fromText(query))).build();

    InMemorySessionService sessionService = (InMemorySessionService) runner.sessionService();
    Session session =
        sessionService
            .createSession(APP_NAME, USER_ID, /* state= */ null, SESSION_ID)
            .blockingGet();

    System.out.println("\n--- Running Query: " + query + " ---");
    final String[] finalResponseText = {"No final text response captured."};

    try {
      runner
          .runAsync(session.userId(), session.id(), content)
          .forEach(
              event -> {
                System.out.println("Event ID: " + event.id() + ", Author: " + event.author());

                boolean hasSpecificPart = false;
                if (event.content().isPresent() && event.content().get().parts().isPresent()) {
                  for (Part part : event.content().get().parts().get()) {
                    if (part.executableCode().isPresent()) {
                      System.out.println(
                          "  Debug: Agent generated code:\n```python\n"
                              + part.executableCode().get().code()
                              + "\n```");
                      hasSpecificPart = true;
                    } else if (part.codeExecutionResult().isPresent()) {
                      System.out.println(
                          "  Debug: Code Execution Result: "
                              + part.codeExecutionResult().get().outcome()
                              + " - Output:\n"
                              + part.codeExecutionResult().get().output());
                      hasSpecificPart = true;
                    } else if (part.text().isPresent() && !part.text().get().trim().isEmpty()) {
                      System.out.println("  Text: '" + part.text().get().trim() + "'");
                    }
                  }
                }

                if (!hasSpecificPart && event.finalResponse()) {
                  if (event.content().isPresent()
                      && event.content().get().parts().isPresent()
                      && !event.content().get().parts().get().isEmpty()
                      && event.content().get().parts().get().get(0).text().isPresent()) {
                    finalResponseText[0] =
                        event.content().get().parts().get().get(0).text().get().trim();
                    System.out.println("==> Final Agent Response: " + finalResponseText[0]);
                  } else {
                    System.out.println(
                        "==> Final Agent Response: [No text content in final event]");
                  }
                }
              });
    } catch (Exception e) {
      System.err.println("ERROR during agent run: " + e.getMessage());
      e.printStackTrace();
    }
    System.out.println("------------------------------");
  }

  public static void main(String[] args) {
    BuiltInCodeExecutionTool codeExecutionTool = new BuiltInCodeExecutionTool();

    BaseAgent codeAgent =
        LlmAgent.builder()
            .name(AGENT_NAME)
            .model(GEMINI_MODEL)
            .tools(ImmutableList.of(codeExecutionTool))
            .instruction(
                """
                                You are a calculator agent.
                                When given a mathematical expression, write and execute Python code to calculate the result.
                                Return only the final numerical result as plain text, without markdown or code blocks.
                                """)
            .description("Executes Python code to perform calculations.")
            .build();

    InMemorySessionService sessionService = new InMemorySessionService();
    Runner runner = new Runner(codeAgent, APP_NAME, null, sessionService);

    callAgent(runner, "Calculate the value of (5 + 7) * 3");
    callAgent(runner, "What is 10 factorial?");
  }
}