What's the difference between MCP and A2A?

MCP connects an agent to tools that run in someone else’s deployment; A2A connects one agent to another so they can hand off a task, and the two are built to run together rather than replace each other.

MCP’s shape is a client calling a passive server: the agent asks a fixed endpoint what tools it offers and calls them over JSON-RPC, the same shape behind any single tool call that can fail in several distinct ways. A2A’s shape is peer to peer. An agent publishes an Agent Card, a JSON document naming its skills and endpoint, so a second agent, possibly built by a different team on a different framework, can discover it and delegate a task without knowing how it works inside.

Google introduced A2A to solve what MCP doesn’t: getting two independent agents to cooperate, not getting one agent to a tool. A system with several agents typically runs both, A2A to move a task between agents and MCP from each agent down to its own tools.

sources

keep reading

More on this.

What's the difference between MCP and Claude Skills?MCP gives Claude access to external tools and data; Skills teach it how to use what it has, loading procedural instructions only when a task calls for them.answer →What's the difference between MCP and LangChain?MCP is an open protocol for exposing tools to any compatible client; LangChain is an orchestration library that, since v1.4, ships a built-in client for consuming MCP servers.answer →What's the difference between MCP and RAG?RAG retrieves material for an answer; MCP is how an agent discovers and calls a tool. A retriever can use MCP, but neither term decides who runs it.answer →Everything on mcp tool reliabilityThe definition, and every question answered under mcp tool reliability.concept →

Two ways to run Tessary.

Tessary is an open-source agent reliability platform. Cloud and self-hosted run the same workflow on the OpenTelemetry traces your agent already emits.

Tessary Cloud

We host it for you. Send your first trace with nothing to deploy and no model key.

what's includedper organization
traces
10,000 per calendar month
stored trace data
1 GB
retention
30 days
model credit
$10, one-time, for triage and root-cause analysis
credit card
not required
start for free

Self-hosted Tessary

Run the open-source code on your own infrastructure with one command. Add your own model key for triage and root-cause analysis.

Self-host Tessary for me by following https://github.com/tessaryai/tessary/blob/main/setup.md

docker compose -f oci://docker.io/tessaryai/tessary:compose up -d -y