Add Python LangChain sample agent

[Yogeshp-MSFT]

Adds a Python sample agent using LangChain/LangGraph with the Microsoft Agent 365 SDK, following existing Python sample patterns.

Files: python/langchain/sample-agent/ — main.py, hosting.py, agent.py, agent_interface.py, mcp_tool_registration_service.py, pyproject.toml, .env.template, ToolingManifest.json, README.md

Highlights:

• LangGraph create_react_agent with MCP tools (Mail + Calendar) via langchain-mcp-adapters
• Supports Azure OpenAI, Azure AI Foundry (/v1), and plain OpenAI
• Agentic auth (OBO flow), JWT middleware, bearer token with expiry check
• Teams patterns: immediate ack, typing indicators, multiple messages
• Email, Word comment, and generic notification handlers
• OpenTelemetry observability with BaggageBuilder
• Comprehensive README with quick start, config reference, deployment, and troubleshooting

Tested: Locally with Agents Playground + deployed on Azure App Service + Teams.

[Copilot]

Pull request overview

Note

Copilot was unable to run its full agentic suite in this review.

Adds a new Python sample agent demonstrating how to host a LangChain/LangGraph “ReAct” agent on the Microsoft Agent 365 SDK, including MCP tool discovery, auth flows, and observability patterns.

Changes:

• Introduces a runnable aiohttp-hosted agent app with Teams-friendly UX (ack + typing loop) and notification handlers.
• Adds MCP tool discovery/registration via langchain-mcp-adapters and A365 tooling services.
• Adds project scaffolding (pyproject, env template, manifest, README) for local dev and Azure deployment.

Reviewed changes

Copilot reviewed 10 out of 10 changed files in this pull request and generated 9 comments.

Show a summary per file

File	Description
python/langchain/sample-agent/pyproject.toml	Defines dependencies and uv/setuptools configuration for the sample.
python/langchain/sample-agent/mcp_tool_registration_service.py	Implements MCP server discovery and tool registration for LangChain.
python/langchain/sample-agent/main.py	Boots the aiohttp server, configures optional JWT auth, enables observability.
python/langchain/sample-agent/hosting.py	Implements AgentApplication handlers (messages, typing loop, notifications).
python/langchain/sample-agent/agent_interface.py	Defines the async interface the hosted agent must implement.
python/langchain/sample-agent/agent.py	Creates the LLM client, loads MCP tools, invokes LangGraph ReAct agent, sets baggage.
python/langchain/sample-agent/ToolingManifest.json	Provides MCP server definitions for Mail and Calendar tools.
python/langchain/sample-agent/README.md	Documents setup, configuration, local testing, and deployment.
python/langchain/sample-agent/.gitignore	Ignores local secrets, build outputs, and A365 generated artifacts.
python/langchain/sample-agent/.env.template	Provides a starting environment configuration for local/prod scenarios.

[Copilot]

Pull request overview

Copilot reviewed 10 out of 10 changed files in this pull request and generated 5 comments.