MCP & Agent Protocols
How AI agents connect to tools and to each other: Model Context Protocol servers and spec changes, A2A, WebMCP, and tool and function calling.
Model Context Protocol turned tool integration from a per-framework chore into something an agent can discover at runtime, and it keeps changing underneath the people who build on it. A spec revision can break a working server overnight, and choosing between MCP, A2A and plain function calling decides how much of your integration survives the next one.
These articles track the protocols as they move: what MCP servers are and how agents use them, the breaking changes in each spec release and the errors they produce, where A2A fits, and WebMCP for agents that work inside a browser.
Start here: MCP (glossary) · Tool use (glossary)
What is WebMCP? When and How to Use WebMCP in a Browser Agent?
The decision is per step, not per site: a page can expose a clean search tool and leave its account settings as ordinary DOM controls, so an agent that picks one mode per domain gets the worst of both.
MCP 2026-07-28: 20 Breaking Changes and the Errors They Cause
MCP 2026-07-28 removed sessions, the initialize handshake and server-initiated requests, and Claude Code now speaks it by default. The full diff, every error you will hit with the fix for each (including 401, invalid_grant and -32000), how to fail so an agent can recover, the DCR to CIMD migration, changing tools without breaking running agents, SDK status on 5 November 2026, and the HTTP+SSE deadline two official sources still disagree about.
PDF Parsing for AI Agents: The Best MCPs and When to Use Each
Streamline your document workflows by integrating PDF parsing with the Model Context Protocol (MCP). This guide explores how to build a standardized interface that allows AI agents to extract and reason over complex PDF data with precision and ease.
MCP Servers Explained: What They Are and How AI Agents Use Them
An MCP server is a program that exposes tools, resources and prompts to an AI application over the Model Context Protocol. Updated 6 November 2026 for the current spec, 2026-07-28: stateless requests, stdio and Streamable HTTP, OAuth 2.1 for remote servers, and a practical guide to choosing between tools, resources and prompts, including where agent memory fits.
A2A vs MCP: What Agent Builders Actually Need to Know
MCP connects an agent to tools and data; A2A connects an agent to other agents. Updated 5 November 2026 for MCP 2026-07-28 (stateless, no sessions), A2A 1.0 under the Agentic AI Foundation, how each protocol authenticates, why every agent-to-agent hop needs its own narrowed token, and what context and memory actually cross the hop.