Building a Production-Ready A2A Protocol Agent: A Technical Journey

#agents #security #ai #python

So, this week came with a new challenge, tasking but interesting. This document chronicles the development of a simple A2A (Agent-to-Agent) Protocol agent built with Python and FastAPI. The agent monitors package dependencies for security vulnerabilities, providing both conversational (Telex) and RESTful interfaces.

Package Health Monitor Agent is an A2A (Agent-to-Agent) Protocol AI Agent built with Python and FastAPI that monitors package dependencies for security vulnerabilities, outdated versions, and deprecated packages. It was designed for Telex integration with natural language processing capabilities.

Its features include: A2A Protocol Support, Multi-Language Support, Security Scanning, Health Scoring, Smart Recommendations, Natural Language and RESTful API with traditional REST endpoints for direct integration

The Problem
This project was carried out as part of the HNG stage tasks. However, modern software projects depend on dozens, sometimes hundreds, of third-party packages. These dependencies can become outdated, vulnerable or deprecated, and developers need a quick, conversational way to check their dependencies' health without context-switching between multiple websites and tools.

This problem led to building this AI agent that:

Accepts natural language queries ("Check flask==2.0.1, requests==2.25.0")
Analyzes packages across multiple ecosystems (Python/PyPI, JavaScript/npm)
Checks real-time vulnerability databases (OSV)
Provides actionable recommendations
Integrates with Telex for conversational workflows

Core Components

FastAPI Application (main_a2a.py)
Modern async web framework
Automatic OpenAPI documentation
Native Pydantic integration for validation
Data Models (models/)
a2a.py - A2A Protocol models (messages, requests, responses)
schemas.py - API request/response models
A2A Handler (a2a_handler.py)
Message processing logic
Natural language parsing
Package analysis orchestration
Package Checker
Integration with external APIs:
PyPI - Python Package Index (https://pypi.org/pypi/{package}/json)
npm - Node Package Manager (https://registry.npmjs.org/{package})
OSV - Open Source Vulnerabilities (https://api.osv.dev/v1/query)
A2A Handler (a2a_handler.py)
Message processing logic
Natural language parsing
Package analysis orchestration
Package Checker
Integration with external APIs:
PyPI - Python Package Index (https://pypi.org/pypi/{package}/json)
npm - Node Package Manager (https://registry.npmjs.org/{package})
OSV - Open Source Vulnerabilities (https://api.osv.dev/v1/query)

Live API: https://packagehealthmonitoragent-2367cacc569a.herokuapp.com/

Documentation: https://packagehealthmonitoragent-2367cacc569a.herokuapp.com/docs

**Technical Stack*

Core Technologies

Technology	Version	Purpose
Python	3.13	Runtime with improved performance
FastAPI	0.115.5	Async web framework
Pydantic	2.10.3	Data validation with strict typing
Uvicorn	0.32.1	ASGI server for production
Requests	2.32.3	HTTP client for external APIs

External APIs

PyPI JSON API - https://pypi.org/pypi/{package}/json
npm Registry - https://registry.npmjs.org/{package}
OSV Database - https://api.osv.dev/v1/query

Development Tools

Git/GitHub - Version control
Heroku - PaaS deployment
Postman - API testing
VS Code - Development environment

Performance Characteristics

Response Times (Average)

/health - <10ms (no external calls)
/check-package - 150-300ms (2 external API calls)
/analyze/python - 500ms-2s (N packages × 2 API calls each)
/a2a - 200ms-2s (depends on message complexity)

Scalability Considerations

Current Limitations:

Sequential package checking (no parallelization)
No caching of PyPI/npm responses
No rate limiting on external APIs

Future Improvements:

Use asyncio.gather() for parallel package checks
Implement Redis cache for package metadata
Add rate limiting with exponential backoff

Code Statistics

Language                 Files        Lines         Code     Comments
────────────────────────────────────────────────────────────────────
Python                       4          850          650          100
Markdown                     2          650          550           50
TOML                         1           20           18            2
Text                         2           15           15            0
────────────────────────────────────────────────────────────────────
Total                        9         1535         1233          152

Test Coverage

A2A Protocol: Tested
Python Package Analysis: Tested
npm Package Analysis: Tested
Error Handling: Tested
Edge Cases: Tested

Resources & References

Documentation

Helpful Articles

"Type Hints in Python" - Real Python
"Building Production-Ready APIs" - FastAPI Best Practices
"Protocol Design Patterns" - Martin Fowler

Tools Used

Poetry - Dependency management (initial)
Postman - API testing
Heroku CLI - Deployment

Conclusion

Building this Package Health Monitor Agent was a journey from simple REST API to enterprise-grade A2A protocol implementation. The key insights:

Start Simple, Refactor Thoughtfully - The initial flexible approach taught us what we needed before committing to strict types.
Protocol Compliance Matters - Proper JSON-RPC 2.0 error codes make debugging integration issues 10x easier.
Type Safety is Worth It - Strict Literal types caught bugs before they reached production.
Production is Different - Logging, error handling, and documentation separate hobby projects from professional tools.
Iterate Based on Real Use - The Telex integration exposed assumptions we didn't know we had.

The agent now serves as a production-ready example of: