---
dimensions:
type:
primary: reference
detail: examples
level: advanced
standard_title: Agent Strategy Plugin
language: zh
title: Agent 策略插件
description: 本文档详细介绍了如何开发Agent策略插件，从初始化插件模板到调用模型、调用工具、输出日志和打包发布的整个过程。文档提供了详尽的代码示例，包括如何实现帮助LLM执行推理或决策逻辑的自动化工具调用功能。
---
Agent 策略插件能够帮助 LLM 执行推理或决策逻辑，包括工具选择、调用和结果处理，以更加自动化的方式处理问题。
本文将演示如何创建一个具备工具调用（Function Calling）能力，自动获取当前准确时间的插件。
### 前置准备
* Dify 插件脚手架工具
* Python 环境，版本号 ≥ 3.12
关于如何准备插件开发的脚手架工具，详细说明请参考[初始化开发工具](/plugin-dev-zh/0221-initialize-development-tools)。
**Tips**：在终端运行 `dify version` 命令，检查是否出现版本号以确认成功安装脚手架工具。
### 1. 初始化插件模板
运行以下命令，初始化 Agent 插件开发模板。
```bash
dify plugin init
```
按照页面提示，填写对应信息。参考以下代码中的备注信息，进行设置。
```
➜ Dify Plugins Developing dify plugin init
Edit profile of the plugin
Plugin name (press Enter to next step): # 填写插件的名称
Author (press Enter to next step): Author name # 填写插件作者
Description (press Enter to next step): Description # 填写插件的描述
---
Select the language you want to use for plugin development, and press Enter to con
BTW, you need Python 3.12+ to develop the Plugin if you choose Python.
-> python # 选择 Python 环境
go (not supported yet)
---
Based on the ability you want to extend, we have divided the Plugin into four type
- Tool: It's a tool provider, but not only limited to tools, you can implement an
- Model: Just a model provider, extending others is not allowed.
- Extension: Other times, you may only need a simple http service to extend the fu
- Agent Strategy: Implement your own logics here, just by focusing on Agent itself
What's more, we have provided the template for you, you can choose one of them b
tool
-> agent-strategy # 选择 Agent 策略模板
llm
text-embedding
---
Configure the permissions of the plugin, use up and down to navigate, tab to sel
Backwards Invocation:
Tools:
Enabled: [✔] You can invoke tools inside Dify if it's enabled # 默认开启
Models:
Enabled: [✔] You can invoke models inside Dify if it's enabled # 默认开启
LLM: [✔] You can invoke LLM models inside Dify if it's enabled # 默认开启
Text Embedding: [✘] You can invoke text embedding models inside Dify if it'
Rerank: [✘] You can invoke rerank models inside Dify if it's enabled
...
```
初始化插件模板后将生成一个代码文件夹，包含插件开发过程中所需的完整资源。熟悉 Agent 策略插件的整体代码结构有助于插件的开发过程。
```text
├── GUIDE.md # User guide and documentation
├── PRIVACY.md # Privacy policy and data handling guidelines
├── README.md # Project overview and setup instructions
├── _assets/ # Static assets directory
│ └── icon.svg # Agent strategy provider icon/logo
├── main.py # Main application entry point
├── manifest.yaml # Basic plugin configuration
├── provider/ # Provider configurations directory
│ └── basic_agent.yaml # Your agent provider settings
├── requirements.txt # Python dependencies list
└── strategies/ # Strategy implementation directory
├── basic_agent.py # Basic agent strategy implementation
└── basic_agent.yaml # Basic agent strategy configuration
```
插件的功能代码集中在 `strategies/` 目录内。
### 2. 开发插件功能
Agent 策略插件的开发主要围绕以下两个文件展开：
* 插件声明文件：`strategies/basic_agent.yaml`
* 插件功能代码：`strategies/basic_agent.py`
#### 2.1 定义参数
要创建一个 Agent 插件，首先需要在 `strategies/basic_agent.yaml` 文件中定义插件所需的参数。这些参数决定了插件的核心功能，例如调用 LLM 模型和使用工具的能力。
建议优先配置以下四个基础参数：
1. **model**：指定要调用的大语言模型（LLM），如 GPT-4、GPT-4o-mini 等。
2. **tools**：定义插件可以使用的工具列表，增强插件功能。
3. **query**：设置与模型交互的提示词或输入内容。
4. **maximum_iterations**：限制插件执行的最大迭代次数，避免过度计算。
示例代码：
```yaml
identity:
name: basic_agent # the name of the agent_strategy
author: novice # the author of the agent_strategy
label:
en_US: BasicAgent # the engilish label of the agent_strategy
description:
en_US: BasicAgent # the english description of the agent_strategy
parameters:
- name: model # the name of the model parameter
type: model-selector # model-type
scope: tool-call&llm # the scope of the parameter
required: true
label:
en_US: Model
zh_Hans: 模型
pt_BR: Model
- name: tools # the name of the tools parameter
type: array[tools] # the type of tool parameter
required: true
label:
en_US: Tools list
zh_Hans: 工具列表
pt_BR: Tools list
- name: query # the name of the query parameter
type: string # the type of query parameter
required: true
label:
en_US: Query
zh_Hans: 查询
pt_BR: Query
- name: maximum_iterations
type: number
required: false
default: 5
label:
en_US: Maxium Iterations
zh_Hans: 最大迭代次数
pt_BR: Maxium Iterations
max: 50 # if you set the max and min value, the display of the parameter will be a slider
min: 1
extra:
python:
source: strategies/basic_agent.py
```
完成参数配置后，插件将在自动生成相应的设置的使用页面，方便你进行直观、便捷的调整和使用。
#### 2.2 获取参数并执行
当使用者在插件的使用页面完成基础的信息填写后，插件需要处理已填写的传入参数。因此需要先在 `strategies/basic_agent.py` 文件内定义 Agent 参数类供后续使用。
校验传入参数：
```python
from dify_plugin.entities.agent import AgentInvokeMessage
from dify_plugin.interfaces.agent import AgentModelConfig, AgentStrategy, ToolEntity
from pydantic import BaseModel
class BasicParams(BaseModel):
maximum_iterations: int
model: AgentModelConfig
tools: list[ToolEntity]
query: str
```
获取参数后，执行具体的业务逻辑：
```python
class BasicAgentAgentStrategy(AgentStrategy):
def _invoke(self, parameters: dict[str, Any]) -> Generator[AgentInvokeMessage]:
params = BasicParams(**parameters)
```
#### 2.3 调用模型
在 Agent 策略插件中，**调用模型**是核心执行逻辑之一。可以通过 SDK 提供的 `session.model.llm.invoke()` 方法高效地调用 LLM 模型，实现文本生成、对话处理等功能。
如果希望模型具备**调用工具**的能力，首先需要确保模型能够输出符合工具调用格式的输入参数。也就是说，模型需要根据用户指令生成符合工具接口要求的参数。
构造以下参数：
* model：模型信息
* prompt\_messages：提示词
* tools：工具信息（Function Calling 相关）
* stop：停止符
* stream：是否支持流式输出
方法定义示例代码：
```python
def invoke(
self,
model_config: LLMModelConfig,
prompt_messages: list[PromptMessage],
tools: list[PromptMessageTool] | None = None,
stop: list[str] | None = None,
stream: bool = True,
) -> Generator[LLMResultChunk, None, None] | LLMResult:...
```
要查看完整的功能实现，请参考模型调用[示例代码](agent-strategy-plugin.md#diao-yong-gong-ju-1)。
该代码实现了以下功能：用户输入指令后，Agent 策略插件会自动调用 LLM，根据生成结果构建并传递工具调用所需的参数，使模型能够灵活调度已接入的工具，高效完成复杂任务。
#### 2.4 为模型添加记忆
当使用 Agent 插件调用模型时，为模型添加记忆功能能够极大提升对话体验。通过记忆功能，模型可以理解完整的对话上下文，实现连贯的交互体验和精准的工具调用。
具体实现步骤：
1. 配置记忆功能
在 Agent 插件的 YAML 配置文件 `strategies/agent.yaml` 中添加 `history-messages` 特性：
```yaml
identity:
name: basic_agent # Agent策略名称
author: novice # 作者
label:
en_US: BasicAgent # 英文标签
description:
en_US: BasicAgent # 英文描述
features:
- history-messages # 启用历史消息功能
...
```
2. 启用记忆设置
修改插件配置文件并重启后，你将在节点配置界面中看到 **记忆** 开关。点击右侧的开关按钮，启用记忆功能。
启用后，您可以通过 **窗口大小** 滑块调整记忆窗口，它决定了模型能够“记住”多少之前的对话内容。
3. 调试历史消息
添加以下代码，查看历史消息内容：
```python
class BasicAgentAgentStrategy(AgentStrategy):
def _invoke(self, parameters: dict[str, Any]) -> Generator[AgentInvokeMessage]:
params = BasicParams(**parameters)
print(f"history_messages: {params.model.history_prompt_messages}")
...
```
控制台将显示类似如下输出：
```
history_messages: []
history_messages: [UserPromptMessage(role=, content='hello, my name is novice', name=None), AssistantPromptMessage(role=, content='Hello, Novice! How can I assist you today?', name=None, tool_calls=[])]
```
4. 将历史消息集成到模型调用
最后，修改模型调用代码，将历史消息拼接到当前查询：
```python
class BasicAgentAgentStrategy(AgentStrategy):
def _invoke(self, parameters: dict[str, Any]) -> Generator[AgentInvokeMessage]:
params = BasicParams(**parameters)
chunks: Generator[LLMResultChunk, None, None] | LLMResult = (
self.session.model.llm.invoke(
model_config=LLMModelConfig(**params.model.model_dump(mode="json")),
# 添加历史消息
prompt_messages=params.model.history_prompt_messages
+ [UserPromptMessage(content=params.query)],
tools=[
self._convert_tool_to_prompt_message_tool(tool)
for tool in params.tools
],
stop=params.model.completion_params.get("stop", [])
if params.model.completion_params
else [],
stream=True,
)
)
...
```
5. 效果验证
添加加记忆功能后，模型能够基于历史对话进行回复。在下图示例中，模型成功地记住了之前对话中提及的用户名称，实现了对话的连贯性。
#### 2.5 调用工具
填写工具参数后，需赋予 Agent 策略插件实际调用工具的能力。可以通过 SDK 中的`session.tool.invoke()` 函数进行工具调用。
构造以下参数：
* provider：工具提供商
* tool\_name：工具名称
* parameters：输入参数
方法定义示例代码：
```python
def invoke(
self,
provider_type: ToolProviderType,
provider: str,
tool_name: str,
parameters: dict[str, Any],
) -> Generator[ToolInvokeMessage, None, None]:...
```
若希望通过 LLM 直接生成参数完成工具调用，请参考以下工具调用的示例代码：
```python
tool_instances = (
{tool.identity.name: tool for tool in params.tools} if params.tools else {}
)
for tool_call_id, tool_call_name, tool_call_args in tool_calls:
tool_instance = tool_instances[tool_call_name]
self.session.tool.invoke(
provider_type=ToolProviderType.BUILT_IN,
provider=tool_instance.identity.provider,
tool_name=tool_instance.identity.name,
parameters={**tool_instance.runtime_parameters, **tool_call_args},
)
```
如需查看完整的功能代码，请阅读调用工具[示例代码](agent-strategy-plugin.md#diao-yong-gong-ju-1)。
实现这部分的功能代码后，Agent 策略插件将具备自动 Function Calling 的能力，例如自动获取当前时间：
#### 2.6 日志创建
在 **Agent 策略插件**中，通常需要执行多轮操作才能完成复杂任务。记录每轮操作的执行结果对于开发者来说非常重要，有助于追踪 Agent 的执行过程、分析每一步的决策依据，从而更好地评估和优化策略效果。
为了实现这一功能，可以利用 SDK 中的 `create_log_message` 和 `finish_log_message` 方法记录日志。这种方式不仅可以在模型调用前后实时记录操作状态，还能帮助开发者快速定位问题。
场景示例：
* 在模型调用之前，记录一条“开始调用模型”的日志，帮助开发者明确任务执行进度。
* 在模型调用成功后，记录一条“调用成功”的日志，方便追踪模型响应的完整性。
```python
model_log = self.create_log_message(
label=f"{params.model.model} Thought",
data={},
metadata={"start_at": model_started_at, "provider": params.model.provider},
status=ToolInvokeMessage.LogMessage.LogStatus.START,
)
yield model_log
self.session.model.llm.invoke(...)
yield self.finish_log_message(
log=model_log,
data={
"output": response,
"tool_name": tool_call_names,
"tool_input": tool_call_inputs,
},
metadata={
"started_at": model_started_at,
"finished_at": time.perf_counter(),
"elapsed_time": time.perf_counter() - model_started_at,
"provider": params.model.provider,
},
)
```
设置完成后，工作流日志将输出执行结果：
在 Agent 执行的过程中，有可能会产生多轮日志。若日志能具备层级结构将有助于开发者查看。通过在日志记录时传入 parent 参数，不同轮次的日志可以形成上下级关系，使日志展示更加清晰、易于追踪。
**引用方法：**
```python
function_call_round_log = self.create_log_message(
label="Function Call Round1 ",
data={},
metadata={},
)
yield function_call_round_log
model_log = self.create_log_message(
label=f"{params.model.model} Thought",
data={},
metadata={"start_at": model_started_at, "provider": params.model.provider},
status=ToolInvokeMessage.LogMessage.LogStatus.START,
# add parent log
parent=function_call_round_log,
)
yield model_log
```
### 插件功能示例代码
#### 调用模型
以下代码将演示如何赋予 Agent 策略插件调用模型的能力：
```python
import json
from collections.abc import Generator
from typing import Any, cast
from dify_plugin.entities.agent import AgentInvokeMessage
from dify_plugin.entities.model.llm import LLMModelConfig, LLMResult, LLMResultChunk
from dify_plugin.entities.model.message import (
PromptMessageTool,
UserPromptMessage,
)
from dify_plugin.entities.tool import ToolInvokeMessage, ToolParameter, ToolProviderType
from dify_plugin.interfaces.agent import AgentModelConfig, AgentStrategy, ToolEntity
from pydantic import BaseModel
class BasicParams(BaseModel):
maximum_iterations: int
model: AgentModelConfig
tools: list[ToolEntity]
query: str
class BasicAgentAgentStrategy(AgentStrategy):
def _invoke(self, parameters: dict[str, Any]) -> Generator[AgentInvokeMessage]:
params = BasicParams(**parameters)
chunks: Generator[LLMResultChunk, None, None] | LLMResult = (
self.session.model.llm.invoke(
model_config=LLMModelConfig(**params.model.model_dump(mode="json")),
prompt_messages=[UserPromptMessage(content=params.query)],
tools=[
self._convert_tool_to_prompt_message_tool(tool)
for tool in params.tools
],
stop=params.model.completion_params.get("stop", [])
if params.model.completion_params
else [],
stream=True,
)
)
response = ""
tool_calls = []
tool_instances = (
{tool.identity.name: tool for tool in params.tools} if params.tools else {}
)
for chunk in chunks:
# check if there is any tool call
if self.check_tool_calls(chunk):
tool_calls = self.extract_tool_calls(chunk)
tool_call_names = ";".join([tool_call[1] for tool_call in tool_calls])
try:
tool_call_inputs = json.dumps(
{tool_call[1]: tool_call[2] for tool_call in tool_calls},
ensure_ascii=False,
)
except json.JSONDecodeError:
# ensure ascii to avoid encoding error
tool_call_inputs = json.dumps(
{tool_call[1]: tool_call[2] for tool_call in tool_calls}
)
print(tool_call_names, tool_call_inputs)
if chunk.delta.message and chunk.delta.message.content:
if isinstance(chunk.delta.message.content, list):
for content in chunk.delta.message.content:
response += content.data
print(content.data, end="", flush=True)
else:
response += str(chunk.delta.message.content)
print(str(chunk.delta.message.content), end="", flush=True)
if chunk.delta.usage:
# usage of the model
usage = chunk.delta.usage
yield self.create_text_message(
text=f"{response or json.dumps(tool_calls, ensure_ascii=False)}\n"
)
result = ""
for tool_call_id, tool_call_name, tool_call_args in tool_calls:
tool_instance = tool_instances[tool_call_name]
tool_invoke_responses = self.session.tool.invoke(
provider_type=ToolProviderType.BUILT_IN,
provider=tool_instance.identity.provider,
tool_name=tool_instance.identity.name,
parameters={**tool_instance.runtime_parameters, **tool_call_args},
)
if not tool_instance:
tool_invoke_responses = {
"tool_call_id": tool_call_id,
"tool_call_name": tool_call_name,
"tool_response": f"there is not a tool named {tool_call_name}",
}
else:
# invoke tool
tool_invoke_responses = self.session.tool.invoke(
provider_type=ToolProviderType.BUILT_IN,
provider=tool_instance.identity.provider,
tool_name=tool_instance.identity.name,
parameters={**tool_instance.runtime_parameters, **tool_call_args},
)
result = ""
for tool_invoke_response in tool_invoke_responses:
if tool_invoke_response.type == ToolInvokeMessage.MessageType.TEXT:
result += cast(
ToolInvokeMessage.TextMessage, tool_invoke_response.message
).text
elif (
tool_invoke_response.type == ToolInvokeMessage.MessageType.LINK
):
result += (
f"result link: {cast(ToolInvokeMessage.TextMessage, tool_invoke_response.message).text}."
+ " please tell user to check it."
)
elif tool_invoke_response.type in {
ToolInvokeMessage.MessageType.IMAGE_LINK,
ToolInvokeMessage.MessageType.IMAGE,
}:
result += (
"image has been created and sent to user already, "
+ "you do not need to create it, just tell the user to check it now."
)
elif (
tool_invoke_response.type == ToolInvokeMessage.MessageType.JSON
):
text = json.dumps(
cast(
ToolInvokeMessage.JsonMessage,
tool_invoke_response.message,
).json_object,
ensure_ascii=False,
)
result += f"tool response: {text}."
else:
result += f"tool response: {tool_invoke_response.message!r}."
tool_response = {
"tool_call_id": tool_call_id,
"tool_call_name": tool_call_name,
"tool_response": result,
}
yield self.create_text_message(result)
def _convert_tool_to_prompt_message_tool(
self, tool: ToolEntity
) -> PromptMessageTool:
"""
convert tool to prompt message tool
"""
message_tool = PromptMessageTool(
name=tool.identity.name,
description=tool.description.llm if tool.description else "",
parameters={
"type": "object",
"properties": {},
"required": [],
},
)
parameters = tool.parameters
for parameter in parameters:
if parameter.form != ToolParameter.ToolParameterForm.LLM:
continue
parameter_type = parameter.type
if parameter.type in {
ToolParameter.ToolParameterType.FILE,
ToolParameter.ToolParameterType.FILES,
}:
continue
enum = []
if parameter.type == ToolParameter.ToolParameterType.SELECT:
enum = (
[option.value for option in parameter.options]
if parameter.options
else []
)
message_tool.parameters["properties"][parameter.name] = {
"type": parameter_type,
"description": parameter.llm_description or "",
}
if len(enum) > 0:
message_tool.parameters["properties"][parameter.name]["enum"] = enum
if parameter.required:
message_tool.parameters["required"].append(parameter.name)
return message_tool
def check_tool_calls(self, llm_result_chunk: LLMResultChunk) -> bool:
"""
Check if there is any tool call in llm result chunk
"""
return bool(llm_result_chunk.delta.message.tool_calls)
def extract_tool_calls(
self, llm_result_chunk: LLMResultChunk
) -> list[tuple[str, str, dict[str, Any]]]:
"""
Extract tool calls from llm result chunk
Returns:
List[Tuple[str, str, Dict[str, Any]]]: [(tool_call_id, tool_call_name, tool_call_args)]
"""
tool_calls = []
for prompt_message in llm_result_chunk.delta.message.tool_calls:
args = {}
if prompt_message.function.arguments != "":
args = json.loads(prompt_message.function.arguments)
tool_calls.append(
(
prompt_message.id,
prompt_message.function.name,
args,
)
)
return tool_calls
```
#### 调用工具
以下代码展示了如何为 Agent 策略插件实现模型调用并向工具发送规范化请求。
```python
import json
from collections.abc import Generator
from typing import Any, cast
from dify_plugin.entities.agent import AgentInvokeMessage
from dify_plugin.entities.model.llm import LLMModelConfig, LLMResult, LLMResultChunk
from dify_plugin.entities.model.message import (
PromptMessageTool,
UserPromptMessage,
)
from dify_plugin.entities.tool import ToolInvokeMessage, ToolParameter, ToolProviderType
from dify_plugin.interfaces.agent import AgentModelConfig, AgentStrategy, ToolEntity
from pydantic import BaseModel
class BasicParams(BaseModel):
maximum_iterations: int
model: AgentModelConfig
tools: list[ToolEntity]
query: str
class BasicAgentAgentStrategy(AgentStrategy):
def _invoke(self, parameters: dict[str, Any]) -> Generator[AgentInvokeMessage]:
params = BasicParams(**parameters)
chunks: Generator[LLMResultChunk, None, None] | LLMResult = (
self.session.model.llm.invoke(
model_config=LLMModelConfig(**params.model.model_dump(mode="json")),
prompt_messages=[UserPromptMessage(content=params.query)],
tools=[
self._convert_tool_to_prompt_message_tool(tool)
for tool in params.tools
],
stop=params.model.completion_params.get("stop", [])
if params.model.completion_params
else [],
stream=True,
)
)
response = ""
tool_calls = []
tool_instances = (
{tool.identity.name: tool for tool in params.tools} if params.tools else {}
)
for chunk in chunks:
# check if there is any tool call
if self.check_tool_calls(chunk):
tool_calls = self.extract_tool_calls(chunk)
tool_call_names = ";".join([tool_call[1] for tool_call in tool_calls])
try:
tool_call_inputs = json.dumps(
{tool_call[1]: tool_call[2] for tool_call in tool_calls},
ensure_ascii=False,
)
except json.JSONDecodeError:
# ensure ascii to avoid encoding error
tool_call_inputs = json.dumps(
{tool_call[1]: tool_call[2] for tool_call in tool_calls}
)
print(tool_call_names, tool_call_inputs)
if chunk.delta.message and chunk.delta.message.content:
if isinstance(chunk.delta.message.content, list):
for content in chunk.delta.message.content:
response += content.data
print(content.data, end="", flush=True)
else:
response += str(chunk.delta.message.content)
print(str(chunk.delta.message.content), end="", flush=True)
if chunk.delta.usage:
# usage of the model
usage = chunk.delta.usage
yield self.create_text_message(
text=f"{response or json.dumps(tool_calls, ensure_ascii=False)}\n"
)
result = ""
for tool_call_id, tool_call_name, tool_call_args in tool_calls:
tool_instance = tool_instances[tool_call_name]
tool_invoke_responses = self.session.tool.invoke(
provider_type=ToolProviderType.BUILT_IN,
provider=tool_instance.identity.provider,
tool_name=tool_instance.identity.name,
parameters={**tool_instance.runtime_parameters, **tool_call_args},
)
if not tool_instance:
tool_invoke_responses = {
"tool_call_id": tool_call_id,
"tool_call_name": tool_call_name,
"tool_response": f"there is not a tool named {tool_call_name}",
}
else:
# invoke tool
tool_invoke_responses = self.session.tool.invoke(
provider_type=ToolProviderType.BUILT_IN,
provider=tool_instance.identity.provider,
tool_name=tool_instance.identity.name,
parameters={**tool_instance.runtime_parameters, **tool_call_args},
)
result = ""
for tool_invoke_response in tool_invoke_responses:
if tool_invoke_response.type == ToolInvokeMessage.MessageType.TEXT:
result += cast(
ToolInvokeMessage.TextMessage, tool_invoke_response.message
).text
elif (
tool_invoke_response.type == ToolInvokeMessage.MessageType.LINK
):
result += (
f"result link: {cast(ToolInvokeMessage.TextMessage, tool_invoke_response.message).text}."
+ " please tell user to check it."
)
elif tool_invoke_response.type in {
ToolInvokeMessage.MessageType.IMAGE_LINK,
ToolInvokeMessage.MessageType.IMAGE,
}:
result += (
"image has been created and sent to user already, "
+ "you do not need to create it, just tell the user to check it now."
)
elif (
tool_invoke_response.type == ToolInvokeMessage.MessageType.JSON
):
text = json.dumps(
cast(
ToolInvokeMessage.JsonMessage,
tool_invoke_response.message,
).json_object,
ensure_ascii=False,
)
result += f"tool response: {text}."
else:
result += f"tool response: {tool_invoke_response.message!r}."
tool_response = {
"tool_call_id": tool_call_id,
"tool_call_name": tool_call_name,
"tool_response": result,
}
yield self.create_text_message(result)
def _convert_tool_to_prompt_message_tool(
self, tool: ToolEntity
) -> PromptMessageTool:
"""
convert tool to prompt message tool
"""
message_tool = PromptMessageTool(
name=tool.identity.name,
description=tool.description.llm if tool.description else "",
parameters={
"type": "object",
"properties": {},
"required": [],
},
)
parameters = tool.parameters
for parameter in parameters:
if parameter.form != ToolParameter.ToolParameterForm.LLM:
continue
parameter_type = parameter.type
if parameter.type in {
ToolParameter.ToolParameterType.FILE,
ToolParameter.ToolParameterType.FILES,
}:
continue
enum = []
if parameter.type == ToolParameter.ToolParameterType.SELECT:
enum = (
[option.value for option in parameter.options]
if parameter.options
else []
)
message_tool.parameters["properties"][parameter.name] = {
"type": parameter_type,
"description": parameter.llm_description or "",
}
if len(enum) > 0:
message_tool.parameters["properties"][parameter.name]["enum"] = enum
if parameter.required:
message_tool.parameters["required"].append(parameter.name)
return message_tool
def check_tool_calls(self, llm_result_chunk: LLMResultChunk) -> bool:
"""
Check if there is any tool call in llm result chunk
"""
return bool(llm_result_chunk.delta.message.tool_calls)
def extract_tool_calls(
self, llm_result_chunk: LLMResultChunk
) -> list[tuple[str, str, dict[str, Any]]]:
"""
Extract tool calls from llm result chunk
Returns:
List[Tuple[str, str, Dict[str, Any]]]: [(tool_call_id, tool_call_name, tool_call_args)]
"""
tool_calls = []
for prompt_message in llm_result_chunk.delta.message.tool_calls:
args = {}
if prompt_message.function.arguments != "":
args = json.loads(prompt_message.function.arguments)
tool_calls.append(
(
prompt_message.id,
prompt_message.function.name,
args,
)
)
return tool_calls
```
#### 完整功能代码示例
包含**调用模型、调用工具**以及**输出多轮日志功能**的完整插件代码示例：
```python
import json
import time
from collections.abc import Generator
from typing import Any, cast
from dify_plugin.entities.agent import AgentInvokeMessage
from dify_plugin.entities.model.llm import LLMModelConfig, LLMResult, LLMResultChunk
from dify_plugin.entities.model.message import (
PromptMessageTool,
UserPromptMessage,
)
from dify_plugin.entities.tool import ToolInvokeMessage, ToolParameter, ToolProviderType
from dify_plugin.interfaces.agent import AgentModelConfig, AgentStrategy, ToolEntity
from pydantic import BaseModel
class BasicParams(BaseModel):
maximum_iterations: int
model: AgentModelConfig
tools: list[ToolEntity]
query: str
class BasicAgentAgentStrategy(AgentStrategy):
def _invoke(self, parameters: dict[str, Any]) -> Generator[AgentInvokeMessage]:
params = BasicParams(**parameters)
function_call_round_log = self.create_log_message(
label="Function Call Round1 ",
data={},
metadata={},
)
yield function_call_round_log
model_started_at = time.perf_counter()
model_log = self.create_log_message(
label=f"{params.model.model} Thought",
data={},
metadata={"start_at": model_started_at, "provider": params.model.provider},
status=ToolInvokeMessage.LogMessage.LogStatus.START,
parent=function_call_round_log,
)
yield model_log
chunks: Generator[LLMResultChunk, None, None] | LLMResult = (
self.session.model.llm.invoke(
model_config=LLMModelConfig(**params.model.model_dump(mode="json")),
prompt_messages=[UserPromptMessage(content=params.query)],
tools=[
self._convert_tool_to_prompt_message_tool(tool)
for tool in params.tools
],
stop=params.model.completion_params.get("stop", [])
if params.model.completion_params
else [],
stream=True,
)
)
response = ""
tool_calls = []
tool_instances = (
{tool.identity.name: tool for tool in params.tools} if params.tools else {}
)
tool_call_names = ""
tool_call_inputs = ""
for chunk in chunks:
# check if there is any tool call
if self.check_tool_calls(chunk):
tool_calls = self.extract_tool_calls(chunk)
tool_call_names = ";".join([tool_call[1] for tool_call in tool_calls])
try:
tool_call_inputs = json.dumps(
{tool_call[1]: tool_call[2] for tool_call in tool_calls},
ensure_ascii=False,
)
except json.JSONDecodeError:
# ensure ascii to avoid encoding error
tool_call_inputs = json.dumps(
{tool_call[1]: tool_call[2] for tool_call in tool_calls}
)
print(tool_call_names, tool_call_inputs)
if chunk.delta.message and chunk.delta.message.content:
if isinstance(chunk.delta.message.content, list):
for content in chunk.delta.message.content:
response += content.data
print(content.data, end="", flush=True)
else:
response += str(chunk.delta.message.content)
print(str(chunk.delta.message.content), end="", flush=True)
if chunk.delta.usage:
# usage of the model
usage = chunk.delta.usage
yield self.finish_log_message(
log=model_log,
data={
"output": response,
"tool_name": tool_call_names,
"tool_input": tool_call_inputs,
},
metadata={
"started_at": model_started_at,
"finished_at": time.perf_counter(),
"elapsed_time": time.perf_counter() - model_started_at,
"provider": params.model.provider,
},
)
yield self.create_text_message(
text=f"{response or json.dumps(tool_calls, ensure_ascii=False)}\n"
)
result = ""
for tool_call_id, tool_call_name, tool_call_args in tool_calls:
tool_instance = tool_instances[tool_call_name]
tool_invoke_responses = self.session.tool.invoke(
provider_type=ToolProviderType.BUILT_IN,
provider=tool_instance.identity.provider,
tool_name=tool_instance.identity.name,
parameters={**tool_instance.runtime_parameters, **tool_call_args},
)
if not tool_instance:
tool_invoke_responses = {
"tool_call_id": tool_call_id,
"tool_call_name": tool_call_name,
"tool_response": f"there is not a tool named {tool_call_name}",
}
else:
# invoke tool
tool_invoke_responses = self.session.tool.invoke(
provider_type=ToolProviderType.BUILT_IN,
provider=tool_instance.identity.provider,
tool_name=tool_instance.identity.name,
parameters={**tool_instance.runtime_parameters, **tool_call_args},
)
result = ""
for tool_invoke_response in tool_invoke_responses:
if tool_invoke_response.type == ToolInvokeMessage.MessageType.TEXT:
result += cast(
ToolInvokeMessage.TextMessage, tool_invoke_response.message
).text
elif (
tool_invoke_response.type == ToolInvokeMessage.MessageType.LINK
):
result += (
f"result link: {cast(ToolInvokeMessage.TextMessage, tool_invoke_response.message).text}."
+ " please tell user to check it."
)
elif tool_invoke_response.type in {
ToolInvokeMessage.MessageType.IMAGE_LINK,
ToolInvokeMessage.MessageType.IMAGE,
}:
result += (
"image has been created and sent to user already, "
+ "you do not need to create it, just tell the user to check it now."
)
elif (
tool_invoke_response.type == ToolInvokeMessage.MessageType.JSON
):
text = json.dumps(
cast(
ToolInvokeMessage.JsonMessage,
tool_invoke_response.message,
).json_object,
ensure_ascii=False,
)
result += f"tool response: {text}."
else:
result += f"tool response: {tool_invoke_response.message!r}."
tool_response = {
"tool_call_id": tool_call_id,
"tool_call_name": tool_call_name,
"tool_response": result,
}
yield self.create_text_message(result)
def _convert_tool_to_prompt_message_tool(
self, tool: ToolEntity
) -> PromptMessageTool:
"""
convert tool to prompt message tool
"""
message_tool = PromptMessageTool(
name=tool.identity.name,
description=tool.description.llm if tool.description else "",
parameters={
"type": "object",
"properties": {},
"required": [],
},
)
parameters = tool.parameters
for parameter in parameters:
if parameter.form != ToolParameter.ToolParameterForm.LLM:
continue
parameter_type = parameter.type
if parameter.type in {
ToolParameter.ToolParameterType.FILE,
ToolParameter.ToolParameterType.FILES,
}:
continue
enum = []
if parameter.type == ToolParameter.ToolParameterType.SELECT:
enum = (
[option.value for option in parameter.options]
if parameter.options
else []
)
message_tool.parameters["properties"][parameter.name] = {
"type": parameter_type,
"description": parameter.llm_description or "",
}
if len(enum) > 0:
message_tool.parameters["properties"][parameter.name]["enum"] = enum
if parameter.required:
message_tool.parameters["required"].append(parameter.name)
return message_tool
def check_tool_calls(self, llm_result_chunk: LLMResultChunk) -> bool:
"""
Check if there is any tool call in llm result chunk
"""
return bool(llm_result_chunk.delta.message.tool_calls)
def extract_tool_calls(
self, llm_result_chunk: LLMResultChunk
) -> list[tuple[str, str, dict[str, Any]]]:
"""
Extract tool calls from llm result chunk
Returns:
List[Tuple[str, str, Dict[str, Any]]]: [(tool_call_id, tool_call_name, tool_call_args)]
"""
tool_calls = []
for prompt_message in llm_result_chunk.delta.message.tool_calls:
args = {}
if prompt_message.function.arguments != "":
args = json.loads(prompt_message.function.arguments)
tool_calls.append(
(
prompt_message.id,
prompt_message.function.name,
args,
)
)
return tool_calls
```
### 3. 调试插件
配置插件的声明文件与功能代码后，在插件的目录内运行 `python -m main` 命令重启插件。接下来需测试插件是否可以正常运行。Dify 提供远程调试方式，前往[“插件管理”](https://cloud.dify.ai/plugins)获取调试 Key 和远程服务器地址。
回到插件项目，拷贝 `.env.example` 文件并重命名为 `.env`，将获取的远程服务器地址和调试 Key 等信息填入至 `REMOTE_INSTALL_HOST` 与 `REMOTE_INSTALL_KEY` 参数内。
```bash
INSTALL_METHOD=remote
REMOTE_INSTALL_URL=debug.dify.ai:5003
REMOTE_INSTALL_KEY=********-****-****-****-************
```
运行 `python -m main` 命令启动插件。在插件页即可看到该插件已被安装至 Workspace 内。其他团队成员也可以访问该插件。
### 打包插件（可选）
确认插件能够正常运行后，可以通过以下命令行工具打包并命名插件。运行以后你可以在当前文件夹发现 `google.difypkg` 文件，该文件为最终的插件包。
```bash
# 将 ./basic_agent 替换为插件项目的实际路径
dify plugin package ./basic_agent/
```
恭喜，你已完成一个工具类型插件的完整开发、调试与打包过程！
### 发布插件（可选）
现在可以将它上传至 [Dify Plugins 代码仓库](https://github.com/langgenius/dify-plugins)来发布你的插件了！上传前，请确保插件已遵循[插件发布规范](https://docs.dify.ai/zh-hans/plugins/publish-plugins/publish-to-dify-marketplace)。审核通过后，代码将合并至主分支并自动上线至 [Dify Marketplace](https://marketplace.dify.ai/)。
### 探索更多
复杂任务往往需要多轮思考和多次工具调用。为了实现更智能的任务处理，通常采用循环执行的策略：**模型调用 → 工具调用**，直到任务完成或达到设定的最大迭代次数。
在这个过程中，提示词（Prompt）管理变得尤为重要。为了高效地组织和动态调整模型输入，建议参考插件内 Function Calling 功能的[完整实现代码](https://github.com/langgenius/dify-official-plugins/blob/main/agent-strategies/cot_agent/strategies/function_calling.py)，了解如何通过标准化的方式来让模型调用外部工具并处理返回结果。
## 相关资源
- [Agent 插件开发基础](/plugin-dev-zh/9232-agent) - 了解 Agent 策略插件的基本概念
- [插件开发基础概念](/plugin-dev-zh/0111-getting-started-dify-plugin) - 了解插件开发的整体架构
- [初始化开发工具](/plugin-dev-zh/0221-initialize-development-tools) - 学习如何搭建开发环境
- [反向调用 Model](/plugin-dev-zh/9242-reverse-invocation-model) - 了解如何调用平台内的模型能力
- [反向调用 Tool](/plugin-dev-zh/9242-reverse-invocation-tool) - 了解如何调用其它插件
- [发布插件概述](/plugin-dev-zh/0321-release-overview) - 学习插件发布流程
{/*
Contributing Section
DO NOT edit this section!
It will be automatically generated by the script.
*/}
---
[编辑此页面](https://github.com/langgenius/dify-docs/edit/main/plugin-dev-zh/9433-agent-strategy-plugin.mdx) | [提交问题](https://github.com/langgenius/dify-docs/issues/new?template=docs.yml)