Hybrid ReAct Agent Service

A sophisticated AI agent system that combines ReAct (Reasoning and Acting) and Plan-Execute paradigms with advanced memory management and context sharing. Built with LangGraph, LangChain, and Google Gemini for intelligent task execution and reasoning.

🚀 Key Features

Core Capabilities

• 🧠 Hybrid Intelligence: Automatically chooses between ReAct and Plan-Execute strategies based on task complexity
• 🔄 ReAct Pattern: Implements Thought-Action-Observation cycles for step-by-step reasoning
• 📋 Plan-Execute Mode: Creates and executes complex multi-step plans for sophisticated tasks
• ⚡ Real-time Thinking: Watch the agent think and reason in real-time as it processes requests
• 🎯 Streaming Interface: Live updates showing thought processes, tool execution, and decision making
• 🧠 Advanced Memory System: Multi-layered memory with episodic, vector, and contextual storage
• 🔗 Context Sharing: Persistent context across tool interactions and sessions
• 🛠️ Extensible Tool System: Modular architecture supporting custom tool integration

Intelligence Modes

1. ReAct Mode: Best for simple queries requiring immediate reasoning and action
2. Plan-Execute Mode: Optimal for complex multi-step tasks requiring upfront planning
3. Hybrid Mode: Intelligently selects the best approach based on query complexity

Built-in Tools

• 📊 Database Tool: Persistent data storage with caching (CRUD operations)
• 📚 Wikipedia Tool: Research and information retrieval
• 🔍 Web Search Tool: Real-time web search capabilities (Serper API)
• 🧮 Calculator Tool: Mathematical computations and functions
• ⚡ C++ Executor Tool: Code compilation and execution
• 🔧 Custom Tools: Easy extension framework for domain-specific tools

Memory & Context

• Episodic Memory: Stores complete interaction episodes for learning
• Vector Memory: Semantic similarity search for relevant past experiences
• Context Manager: Maintains session state and tool interaction history
• Memory Store: Multi-type storage (conversational, episodic, tool-specific)

🧠 Adaptive Thinking Flow

The hybrid React Agent features sophisticated adaptive thinking that intelligently switches between different reasoning approaches based on real-time evaluation and learning from past experiences.

Key Innovation: Dynamic Approach Switching

• Intelligent Decision Making: Uses query complexity analysis and episodic memory similarity to choose optimal approach
• Real-time Evaluation: Continuously assesses execution success and adapts strategy mid-flow
• Adaptive Replanning: Creates new plans when initial execution fails, with intelligent fallback mechanisms
• Memory-Informed Learning: Leverages past episodes to improve decision making over time

Adaptive Flow Features

1. Approach Selection: Automatically determines whether to use Plan-Execute or ReAct based on:

   • Query complexity indicators (multiple steps, calculations, comparisons)
   • Similarity to successful past episodes
   • Tool usage patterns from historical data

2. Execution Evaluation: After plan execution, evaluates:

   • Success rate (≥70% threshold for completion)
   • Task completion status
   • Quality of results

3. Adaptive Replanning: When plans fail:

   • Generates new strategies with different approaches
   • Can switch from Plan-Execute to ReAct mid-execution
   • Prevents infinite loops with attempt limits
   • Graceful degradation to simpler approaches

4. Seamless Integration: ReAct and Plan-Execute modes work together:

   • ReAct serves as fallback for failed plans
   • Plan-Execute handles complex multi-step reasoning
   • Memory system learns from both approaches

Visual Flow & Documentation

• Adaptive React Agent Thinking Flow: Detailed Mermaid diagram showing the complete decision and execution flow
• Adaptive Replanning Analysis: In-depth analysis of the replanning mechanisms and strategies

Benefits

• Robustness: Multiple fallback mechanisms prevent complete failures
• Efficiency: Uses the most appropriate approach for each query type
• Learning: Improves over time based on execution history
• Flexibility: Can handle both simple and complex queries effectively

📁 Project Architecture

react-agent-service/
├── agent/                    # Core agent implementation
│   ├── react_agent.py      # Main hybrid agent with mode switching
│   ├── planner.py           # Planning system for complex tasks
│   ├── executor.py          # Plan execution engine
│   ├── agent_state.py       # State management and data structures
│   ├── tool_manager.py      # Tool orchestration and management
│   └── planner_execution.mmd # Execution flow diagram
├── tools/                   # Tool implementations
│   ├── base_tool.py        # Abstract base class for all tools
│   ├── database_tool.py    # Persistent data operations
│   ├── wikipedia_tool.py   # Wikipedia search and retrieval
│   ├── web_search_tool.py  # Web search capabilities
│   ├── calculator_tool.py  # Mathematical computations
│   └── cpp_executor_tool.py # Code execution environment
├── memory/                  # Advanced memory system
│   ├── memory_store.py     # Core memory storage
│   ├── vector_memory.py    # Semantic search capabilities
│   ├── context_manager.py  # Session and context management
│   └── episodic_memory.py  # Episode storage and retrieval
├── examples/               # Usage examples and demos
│   ├── hybrid_agent_demo.py # Comprehensive demonstration
│   └── example_usage.py    # Basic usage examples
├── extensions/             # Future extensions and frameworks
│   └── multiagent_framework.py # Multi-agent system foundation
├── web_interface.py        # Streamlit web UI
├── chatbot.py             # Console interface
├── llm_manager.py         # LLM session management
├── config.py              # Configuration management
└── requirements.txt       # Dependencies

🔧 Installation & Setup

Prerequisites

• Python 3.8+
• Google Gemini API key
• Optional: Serper API key for web search

Quick Start

1. Clone and Install

git clone <repository-url>
cd react-agent-service
pip install -r requirements.txt

2. Configure Environment

cp .env.example .env
# Edit .env and add your API keys:
# GOOGLE_API_KEY=your_gemini_api_key
# SERPER_API_KEY=your_serper_api_key (optional)

3. Run the Agent

# Interactive launcher (recommended)
python3 launch_ui.py

# Real-time thinking web interface
streamlit run web_interface_streaming.py

# Standard web interface
streamlit run web_interface.py

# Console interface
python3 chatbot.py

# Streaming demo (console)
python3 demo_streaming.py

# Hybrid demo
python3 examples/hybrid_agent_demo.py

💡 Usage Examples

Basic Programmatic Usage

import asyncio
from agent.react_agent import ReactAgent

async def main():
    # Create hybrid agent (auto-selects best mode)
    agent = ReactAgent(verbose=True, mode="hybrid")
    
    # Simple query (will use ReAct)
    response = await agent.run("What is 2 + 2?")
    print(f"Result: {response['output']}")
    
    # Complex query (will use Plan-Execute)
    complex_query = """
    Calculate the square root of 144, then search for information 
    about that number in mathematics, and store both results 
    in the database
    """
    response = await agent.run(complex_query)
    print(f"Success: {response['success']}")
    print(f"Mode used: {response['metadata']['chosen_approach']}")

asyncio.run(main())

Mode-Specific Usage

# Force ReAct mode for step-by-step reasoning
react_agent = ReactAgent(mode="react")

# Force Plan-Execute mode for complex planning
planner_agent = ReactAgent(mode="plan_execute")

# Hybrid mode (recommended) - auto-selects best approach
hybrid_agent = ReactAgent(mode="hybrid")

Advanced Memory Features

# Access memory statistics
stats = await agent.get_memory_stats()
print(f"Episodes stored: {stats.get('episodes', 0)}")

# Memory persists across sessions for context sharing
response1 = await agent.run("Store my name as Alice")
response2 = await agent.run("What's my name?")  # Remembers Alice

Real-time Streaming Usage

import asyncio
from streaming_agent import StreamingChatbot, EventType

async def watch_agent_think():
    chatbot = StreamingChatbot(verbose=False, mode="hybrid")
    
    query = "Calculate 144 squared root and tell me about it"
    
    async for event in chatbot.chat_stream(query):
        if event.type == EventType.THINKING:
            print(f"🤔 Agent is thinking: {event.data['thought']}")
        
        elif event.type == EventType.ACTION_START:
            print(f"🔧 Executing: {event.data['action']}")
        
        elif event.type == EventType.COMPLETE:
            print(f"✅ Final answer: {event.data['response']['output']}")
            break

asyncio.run(watch_agent_think())

🏗️ Architecture Deep Dive

Adaptive Execution Flow (Hybrid Mode)

flowchart TD
    START([🚀 Query Input]) --> DECIDE{🤔 Decide Approach}
    
    %% Decision Logic with Memory Integration
    DECIDE -->|Complex Query<br/>+ Past Success| PLAN[📋 Plan]
    DECIDE -->|Simple Query<br/>+ Direct Action| THINK[💭 Think]
    
    %% Plan-Execute Path with Evaluation
    PLAN --> EXECUTE[⚡ Execute Plan]
    EXECUTE --> EVALUATE{📊 Evaluate Execution}
    
    %% Smart Evaluation Outcomes
    EVALUATE -->|Success ≥70%<br/>Complete| FINISH([✅ Response])
    EVALUATE -->|Plan Failed<br/>Replan Needed| REPLAN[🔄 Adaptive Replan]
    EVALUATE -->|Unsatisfactory<br/>Switch Mode| THINK
    
    %% Adaptive Replanning with Strategy Switching
    REPLAN -->|New Plan<br/>Retry| PLAN
    REPLAN -->|Switch Strategy<br/>to ReAct| THINK
    REPLAN -->|Max Attempts<br/>Fallback| THINK
    REPLAN -->|No Solution<br/>Give Up| FINISH
    
    %% Enhanced ReAct Loop
    THINK -->|Need Action<br/>Continue| ACT[🔧 Act]
    THINK -->|Complete<br/>or Max Steps| FINISH
    
    ACT --> OBSERVE[👁️ Observe]
    OBSERVE --> THINK
    
    %% Memory Integration (shown as influence)
    MEMORY[(🧠 Episodic<br/>Memory)] -.->|Similarity<br/>Matching| DECIDE
    MEMORY -.->|Learning<br/>from Episodes| REPLAN
    
    %% Styling
    classDef startEnd fill:#e1f5fe,stroke:#01579b,stroke-width:3px
    classDef decision fill:#fff3e0,stroke:#ef6c00,stroke-width:2px
    classDef planPath fill:#e8f5e8,stroke:#2e7d32,stroke-width:2px
    classDef reactPath fill:#fce4ec,stroke:#c2185b,stroke-width:2px
    classDef adaptive fill:#f3e5f5,stroke:#7b1fa2,stroke-width:2px
    classDef memory fill:#e8eaf6,stroke:#3f51b5,stroke-width:2px
    
    class START,FINISH startEnd
    class DECIDE,EVALUATE decision
    class PLAN,EXECUTE planPath
    class THINK,ACT,OBSERVE reactPath
    class REPLAN adaptive
    class MEMORY memory

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Memory Architecture

graph LR
    Query --> CM[Context Manager]
    CM --> MS[Memory Store]
    MS --> EM[Episodic Memory]
    MS --> VM[Vector Memory]
    VM --> Embeddings[Vector Embeddings]
    EM --> Episodes[Stored Episodes]
    CM --> Tools[Tool Contexts]

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Tool Integration Pattern

from tools.base_tool import BaseTool, ToolResult

class CustomTool(BaseTool):
    def __init__(self):
        super().__init__("custom_tool", "My custom tool description")
    
    async def execute(self, query: str, **kwargs) -> ToolResult:
        # Your tool logic here
        result = process_query(query)
        return ToolResult(success=True, data=result)
    
    def get_schema(self):
        return {
            "type": "object",
            "properties": {
                "query": {"type": "string", "description": "Input query"}
            }
        }

🎯 Use Cases

Simple Queries (ReAct Mode)

• Mathematical calculations
• Information lookup
• Single-step operations
• Quick fact retrieval

Complex Tasks (Plan-Execute Mode)

• Multi-step research projects
• Data processing pipelines
• Complex calculations with dependencies
• Workflow automation

Hybrid Intelligence

• Travel planning with budget calculations
• Research with data storage
• Code generation and execution
• Multi-domain problem solving

⚙️ Configuration

Key settings in config.py:

# Model settings
GEMINI_MODEL = "gemini-2.0-flash-lite"
TEMPERATURE = 0.1
MAX_TOKENS = 1000

# Agent behavior
MAX_ITERATIONS = 10
VERBOSE = True

# Memory settings
CACHE_TTL = 3600  # 1 hour
MAX_CACHE_SIZE = 1000

🧪 Testing & Examples

Run the comprehensive demo:

python examples/hybrid_agent_demo.py

Test specific components:

python test_agent.py
python test_memory_integration.py

🔍 Monitoring & Debugging

Verbose Mode

Enable detailed logging:

agent = ReactAgent(verbose=True)

Memory Statistics

stats = await agent.get_memory_stats()
print(json.dumps(stats, indent=2))

Execution Metadata

response = await agent.run("query")
print(f"Mode used: {response['metadata']['chosen_approach']}")
print(f"Steps taken: {len(response['steps'])}")
print(f"Execution time: {response['metadata']['execution_time']:.2f}s")

🚧 Extending the System

Adding Custom Tools

1. Inherit from BaseTool
2. Implement execute() and get_schema() methods
3. Register in ToolManager

Custom Memory Types

1. Extend MemoryStore with new memory types
2. Implement storage and retrieval logic
3. Integrate with ContextManager

Multi-Agent Extensions

from extensions.multiagent_framework import MultiAgentSystem

system = MultiAgentSystem()
system.add_agent("researcher", researcher_agent)
system.add_agent("analyzer", analyzer_agent)

result = await system.distribute_task({
    "type": "research_and_analyze",
    "query": "Latest AI developments"
})

📊 Performance Considerations

• Memory Optimization: Automatic cleanup of old sessions
• Caching: Built-in result caching for database operations
• Parallel Execution: Plan-Execute mode supports parallel step execution
• Session Management: Efficient LLM session handling

🔒 Security & Privacy

• API keys stored in environment variables
• No persistent storage of sensitive data
• Session isolation for multi-user environments
• Configurable cache TTL for data expiration

📚 References & Research

This implementation is based on:

• ReAct: Synergizing Reasoning and Acting in Language Models
• Plan-and-Solve Prompting
• LangGraph Documentation

🤝 Contributing

1. Fork the repository
2. Create a feature branch (git checkout -b feature/amazing-feature)
3. Commit your changes (git commit -m 'Add amazing feature')
4. Push to the branch (git push origin feature/amazing-feature)
5. Open a Pull Request

📝 License

MIT License - see LICENSE file for details.

🆘 Troubleshooting

Common Issues

ImportError with langchain packages

pip install --upgrade langchain langgraph langchain-google-genai

API Key Issues

# Check environment variables
echo $GOOGLE_API_KEY

Memory/Performance Issues

# Adjust configuration
Config.MAX_CACHE_SIZE = 500
Config.CACHE_TTL = 1800

Debug Mode

import logging
logging.basicConfig(level=logging.DEBUG)

agent = ReactAgent(verbose=True)

🎉 What's Next?

• Multi-modal tool support (image, audio)
• Distributed multi-agent systems
• Fine-tuning capabilities
• Integration with external APIs
• Performance optimization
• Advanced planning algorithms

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Built with ❤️ using LangGraph, LangChain, and Google Gemini