# MCPConfig now rejects unknown fields

> MCPConfig now raises on fields it doesn't recognize, so a typo like tool= instead of tools= fails at construction instead of being silently ignored.

- Published: 2026-08-30
- Author: Ashpreet Bedi
- Categories: Changelog
- Canonical: https://www.agno.com/articles/mcpconfig-now-rejects-unknown-fields
- Markdown: https://www.agno.com/articles/mcpconfig-now-rejects-unknown-fields.md

We made `MCPConfig` strict about the fields you hand it. Pass one it does not recognize and it raises at construction, so a typo like `tool=` instead of `tools=` fails right away instead of being dropped without a word.

Before, an unknown field was ignored, so a misspelled option looked like it applied but did nothing. Now you find out the moment you build the config.

It is worth a look when you upgrade a working config, since a typo we used to tolerate will now raise.

Learn more about the [AgentOS MCP server](https://docs.agno.com/features/mcp-server) in the documentation.