feat: integrate todo middleware

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hetaoBackend
2026-01-20 22:38:04 +08:00
parent c5a2771636
commit 7ead7c93f8
2 changed files with 339 additions and 4 deletions

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# Plan Mode with TodoList Middleware
This document describes how to enable and use the Plan Mode feature with TodoList middleware in DeerFlow 2.0.
## Overview
Plan Mode adds a TodoList middleware to the agent, which provides a `write_todos` tool that helps the agent:
- Break down complex tasks into smaller, manageable steps
- Track progress as work progresses
- Provide visibility to users about what's being done
The TodoList middleware is built on LangChain's `TodoListMiddleware`.
## Configuration
### Enabling Plan Mode
Plan mode is controlled via **runtime configuration** through the `is_plan_mode` parameter in the `configurable` section of `RunnableConfig`. This allows you to dynamically enable or disable plan mode on a per-request basis.
```python
from langchain_core.runnables import RunnableConfig
from src.agents.lead_agent.agent import make_lead_agent
# Enable plan mode via runtime configuration
config = RunnableConfig(
configurable={
"thread_id": "example-thread",
"thinking_enabled": True,
"is_plan_mode": True, # Enable plan mode
}
)
# Create agent with plan mode enabled
agent = make_lead_agent(config)
```
### Configuration Options
- **is_plan_mode** (bool): Whether to enable plan mode with TodoList middleware. Default: `False`
- Pass via `config.get("configurable", {}).get("is_plan_mode", False)`
- Can be set dynamically for each agent invocation
- No global configuration needed
## Default Behavior
When plan mode is enabled with default settings, the agent will have access to a `write_todos` tool with the following behavior:
### When to Use TodoList
The agent will use the todo list for:
1. Complex multi-step tasks (3+ distinct steps)
2. Non-trivial tasks requiring careful planning
3. When user explicitly requests a todo list
4. When user provides multiple tasks
### When NOT to Use TodoList
The agent will skip using the todo list for:
1. Single, straightforward tasks
2. Trivial tasks (< 3 steps)
3. Purely conversational or informational requests
### Task States
- **pending**: Task not yet started
- **in_progress**: Currently working on (can have multiple parallel tasks)
- **completed**: Task finished successfully
## Usage Examples
### Basic Usage
```python
from langchain_core.runnables import RunnableConfig
from src.agents.lead_agent.agent import make_lead_agent
# Create agent with plan mode ENABLED
config_with_plan_mode = RunnableConfig(
configurable={
"thread_id": "example-thread",
"thinking_enabled": True,
"is_plan_mode": True, # TodoList middleware will be added
}
)
agent_with_todos = make_lead_agent(config_with_plan_mode)
# Create agent with plan mode DISABLED (default)
config_without_plan_mode = RunnableConfig(
configurable={
"thread_id": "another-thread",
"thinking_enabled": True,
"is_plan_mode": False, # No TodoList middleware
}
)
agent_without_todos = make_lead_agent(config_without_plan_mode)
```
### Dynamic Plan Mode per Request
You can enable/disable plan mode dynamically for different conversations or tasks:
```python
from langchain_core.runnables import RunnableConfig
from src.agents.lead_agent.agent import make_lead_agent
def create_agent_for_task(task_complexity: str):
"""Create agent with plan mode based on task complexity."""
is_complex = task_complexity in ["high", "very_high"]
config = RunnableConfig(
configurable={
"thread_id": f"task-{task_complexity}",
"thinking_enabled": True,
"is_plan_mode": is_complex, # Enable only for complex tasks
}
)
return make_lead_agent(config)
# Simple task - no TodoList needed
simple_agent = create_agent_for_task("low")
# Complex task - TodoList enabled for better tracking
complex_agent = create_agent_for_task("high")
```
## How It Works
1. When `make_lead_agent(config)` is called, it extracts `is_plan_mode` from `config.configurable`
2. The config is passed to `_build_middlewares(config)`
3. `_build_middlewares()` reads `is_plan_mode` and calls `_create_todo_list_middleware(is_plan_mode)`
4. If `is_plan_mode=True`, a `TodoListMiddleware` instance is created and added to the middleware chain
5. The middleware automatically adds a `write_todos` tool to the agent's toolset
6. The agent can use this tool to manage tasks during execution
7. The middleware handles the todo list state and provides it to the agent
## Architecture
```
make_lead_agent(config)
├─> Extracts: is_plan_mode = config.configurable.get("is_plan_mode", False)
└─> _build_middlewares(config)
├─> ThreadDataMiddleware
├─> SandboxMiddleware
├─> SummarizationMiddleware (if enabled via global config)
├─> TodoListMiddleware (if is_plan_mode=True) ← NEW
├─> TitleMiddleware
└─> ClarificationMiddleware
```
## Implementation Details
### Agent Module
- **Location**: `src/agents/lead_agent/agent.py`
- **Function**: `_create_todo_list_middleware(is_plan_mode: bool)` - Creates TodoListMiddleware if plan mode is enabled
- **Function**: `_build_middlewares(config: RunnableConfig)` - Builds middleware chain based on runtime config
- **Function**: `make_lead_agent(config: RunnableConfig)` - Creates agent with appropriate middlewares
### Runtime Configuration
Plan mode is controlled via the `is_plan_mode` parameter in `RunnableConfig.configurable`:
```python
config = RunnableConfig(
configurable={
"is_plan_mode": True, # Enable plan mode
# ... other configurable options
}
)
```
## Key Benefits
1. **Dynamic Control**: Enable/disable plan mode per request without global state
2. **Flexibility**: Different conversations can have different plan mode settings
3. **Simplicity**: No need for global configuration management
4. **Context-Aware**: Plan mode decision can be based on task complexity, user preferences, etc.
## Custom Prompts
DeerFlow uses custom `system_prompt` and `tool_description` for the TodoListMiddleware that match the overall DeerFlow prompt style:
### System Prompt Features
- Uses XML tags (`<todo_list_system>`) for structure consistency with DeerFlow's main prompt
- Emphasizes CRITICAL rules and best practices
- Clear "When to Use" vs "When NOT to Use" guidelines
- Focuses on real-time updates and immediate task completion
### Tool Description Features
- Detailed usage scenarios with examples
- Strong emphasis on NOT using for simple tasks
- Clear task state definitions (pending, in_progress, completed)
- Comprehensive best practices section
- Task completion requirements to prevent premature marking
The custom prompts are defined in `_create_todo_list_middleware()` in `/Users/hetao/workspace/deer-flow/backend/src/agents/lead_agent/agent.py:57`.
## Notes
- TodoList middleware uses LangChain's built-in `TodoListMiddleware` with **custom DeerFlow-style prompts**
- Plan mode is **disabled by default** (`is_plan_mode=False`) to maintain backward compatibility
- The middleware is positioned before `ClarificationMiddleware` to allow todo management during clarification flows
- Custom prompts emphasize the same principles as DeerFlow's main system prompt (clarity, action-oriented, critical rules)

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from langchain.agents import create_agent
from langchain.agents.middleware import SummarizationMiddleware
from langchain.agents.middleware import SummarizationMiddleware, TodoListMiddleware
from langchain_core.runnables import RunnableConfig
from src.agents.lead_agent.prompt import apply_prompt_template
@@ -54,10 +54,134 @@ def _create_summarization_middleware() -> SummarizationMiddleware | None:
return SummarizationMiddleware(**kwargs)
def _create_todo_list_middleware(is_plan_mode: bool) -> TodoListMiddleware | None:
"""Create and configure the TodoList middleware.
Args:
is_plan_mode: Whether to enable plan mode with TodoList middleware.
Returns:
TodoListMiddleware instance if plan mode is enabled, None otherwise.
"""
if not is_plan_mode:
return None
# Custom prompts matching DeerFlow's style
system_prompt = """
<todo_list_system>
You have access to the `write_todos` tool to help you manage and track complex multi-step objectives.
**CRITICAL RULES:**
- Mark todos as completed IMMEDIATELY after finishing each step - do NOT batch completions
- Keep EXACTLY ONE task as `in_progress` at any time (unless tasks can run in parallel)
- Update the todo list in REAL-TIME as you work - this gives users visibility into your progress
- DO NOT use this tool for simple tasks (< 3 steps) - just complete them directly
**When to Use:**
This tool is designed for complex objectives that require systematic tracking:
- Complex multi-step tasks requiring 3+ distinct steps
- Non-trivial tasks needing careful planning and execution
- User explicitly requests a todo list
- User provides multiple tasks (numbered or comma-separated list)
- The plan may need revisions based on intermediate results
**When NOT to Use:**
- Single, straightforward tasks
- Trivial tasks (< 3 steps)
- Purely conversational or informational requests
- Simple tool calls where the approach is obvious
**Best Practices:**
- Break down complex tasks into smaller, actionable steps
- Use clear, descriptive task names
- Remove tasks that become irrelevant
- Add new tasks discovered during implementation
- Don't be afraid to revise the todo list as you learn more
**Task Management:**
Writing todos takes time and tokens - use it when helpful for managing complex problems, not for simple requests.
</todo_list_system>
"""
tool_description = """Use this tool to create and manage a structured task list for complex work sessions.
**IMPORTANT: Only use this tool for complex tasks (3+ steps). For simple requests, just do the work directly.**
## When to Use
Use this tool in these scenarios:
1. **Complex multi-step tasks**: When a task requires 3 or more distinct steps or actions
2. **Non-trivial tasks**: Tasks requiring careful planning or multiple operations
3. **User explicitly requests todo list**: When the user directly asks you to track tasks
4. **Multiple tasks**: When users provide a list of things to be done
5. **Dynamic planning**: When the plan may need updates based on intermediate results
## When NOT to Use
Skip this tool when:
1. The task is straightforward and takes less than 3 steps
2. The task is trivial and tracking provides no benefit
3. The task is purely conversational or informational
4. It's clear what needs to be done and you can just do it
## How to Use
1. **Starting a task**: Mark it as `in_progress` BEFORE beginning work
2. **Completing a task**: Mark it as `completed` IMMEDIATELY after finishing
3. **Updating the list**: Add new tasks, remove irrelevant ones, or update descriptions as needed
4. **Multiple updates**: You can make several updates at once (e.g., complete one task and start the next)
## Task States
- `pending`: Task not yet started
- `in_progress`: Currently working on (can have multiple if tasks run in parallel)
- `completed`: Task finished successfully
## Task Completion Requirements
**CRITICAL: Only mark a task as completed when you have FULLY accomplished it.**
Never mark a task as completed if:
- There are unresolved issues or errors
- Work is partial or incomplete
- You encountered blockers preventing completion
- You couldn't find necessary resources or dependencies
- Quality standards haven't been met
If blocked, keep the task as `in_progress` and create a new task describing what needs to be resolved.
## Best Practices
- Create specific, actionable items
- Break complex tasks into smaller, manageable steps
- Use clear, descriptive task names
- Update task status in real-time as you work
- Mark tasks complete IMMEDIATELY after finishing (don't batch completions)
- Remove tasks that are no longer relevant
- **IMPORTANT**: When you write the todo list, mark your first task(s) as `in_progress` immediately
- **IMPORTANT**: Unless all tasks are completed, always have at least one task `in_progress` to show progress
Being proactive with task management demonstrates thoroughness and ensures all requirements are completed successfully.
**Remember**: If you only need a few tool calls to complete a task and it's clear what to do, it's better to just do the task directly and NOT use this tool at all.
"""
return TodoListMiddleware(system_prompt=system_prompt, tool_description=tool_description)
# ThreadDataMiddleware must be before SandboxMiddleware to ensure thread_id is available
# SummarizationMiddleware should be early to reduce context before other processing
# TodoListMiddleware should be before ClarificationMiddleware to allow todo management
# ClarificationMiddleware should be last to intercept clarification requests after model calls
def _build_middlewares():
def _build_middlewares(config: RunnableConfig):
"""Build middleware chain based on runtime configuration.
Args:
config: Runtime configuration containing configurable options like is_plan_mode.
Returns:
List of middleware instances.
"""
middlewares = [ThreadDataMiddleware(), SandboxMiddleware()]
# Add summarization middleware if enabled
@@ -65,6 +189,12 @@ def _build_middlewares():
if summarization_middleware is not None:
middlewares.append(summarization_middleware)
# Add TodoList middleware if plan mode is enabled
is_plan_mode = config.get("configurable", {}).get("is_plan_mode", False)
todo_list_middleware = _create_todo_list_middleware(is_plan_mode)
if todo_list_middleware is not None:
middlewares.append(todo_list_middleware)
middlewares.extend([TitleMiddleware(), ClarificationMiddleware()])
return middlewares
@@ -75,11 +205,12 @@ def make_lead_agent(config: RunnableConfig):
thinking_enabled = config.get("configurable", {}).get("thinking_enabled", True)
model_name = config.get("configurable", {}).get("model_name") or config.get("configurable", {}).get("model")
print(f"thinking_enabled: {thinking_enabled}, model_name: {model_name}")
is_plan_mode = config.get("configurable", {}).get("is_plan_mode", False)
print(f"thinking_enabled: {thinking_enabled}, model_name: {model_name}, is_plan_mode: {is_plan_mode}")
return create_agent(
model=create_chat_model(name=model_name, thinking_enabled=thinking_enabled),
tools=get_available_tools(),
middleware=_build_middlewares(),
middleware=_build_middlewares(config),
system_prompt=apply_prompt_template(),
state_schema=ThreadState,
)