What's the difference between MCP and a plain API call?

With a direct API integration, your code names the endpoint and request shape. An MCP client asks a server what tools it offers, reads their schemas, then calls one. You can run that MCP server yourself, just as you can call someone else’s plain API.

An MCP client can keep building calls against a stale tools/list result after the server changes its schema. A direct API integration can break when a vendor changes an endpoint your code still calls. The cached MCP tool list is the difference to inspect; server ownership tells you neither contract is safe from change.

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More on this.

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 delegate a task, and both usually run together.answer →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 →Everything on mcp tool reliabilityThe definition, and every question answered under mcp tool reliability.concept →

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

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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