Add Langchain external search tool examples for PraisonAI agents

- Introduced example scripts for Brave Search, Google Trends, and SerpAPI
- Demonstrated multi-agent workflows using external search tools
- Added API key configuration instructions for each search tool
- Included examples of research and content generation agents using search capabilities

examples/tools/langchain/brave-search.py

@@ -0,0 +1,18 @@
+# pip install langchain-community 
+# export BRAVE_SEARCH_API=your_api_key_here
+# export OPENAI_API_KEY=your_api_key_here
+
+from praisonaiagents import Agent, PraisonAIAgents
+from langchain_community.tools import BraveSearch
+import os
+
+def search_brave(query: str):
+    """Searches using BraveSearch and returns results."""
+    api_key = os.environ['BRAVE_SEARCH_API']
+    tool = BraveSearch.from_api_key(api_key=api_key, search_kwargs={"count": 3})
+    return tool.run(query)
+
+data_agent = Agent(instructions="Search about AI job trends in 2025", tools=[search_brave])
+editor_agent = Agent(instructions="Write a blog article")
+agents = PraisonAIAgents(agents=[data_agent, editor_agent])
+agents.start()

examples/tools/langchain/google-trends.py

@@ -0,0 +1,18 @@
+# pip install langchain-community google-search-results
+# export SERPAPI_API_KEY=your_api_key_here
+# export OPENAI_API_KEY=your_api_key_here
+
+from langchain_community.utilities.google_trends import GoogleTrendsAPIWrapper
+from praisonaiagents import Agent, PraisonAIAgents
+
+research_agent = Agent(
+    instructions="Research trending topics related to AI",
+    tools=[GoogleTrendsAPIWrapper]
+)
+
+summarise_agent = Agent(
+    instructions="Summarise findings from the research agent",
+)
+
+agents = PraisonAIAgents(agents=[research_agent, summarise_agent])
+agents.start()

examples/tools/langchain/serp-api.py

@@ -0,0 +1,12 @@
+# pip install langchain-community google-search-results
+# export SERPAPI_API_KEY=your_api_key_here
+# export OPENAI_API_KEY=your_api_key_here
+
+from praisonaiagents import Agent, PraisonAIAgents
+from langchain_community.utilities import SerpAPIWrapper
+
+data_agent = Agent(instructions="Search about AI job trends in 2025", tools=[SerpAPIWrapper])
+editor_agent = Agent(instructions="Write a blog article")
+
+agents = PraisonAIAgents(agents=[data_agent, editor_agent])
+agents.start()