# Strict-mode tool schemas without a properties field no longer error

> Strict mode no longer raises a KeyError when a tool schema leaves out the properties key, so schemas registered verbatim, including MCP server schemas, now work.

- Published: 2026-08-26
- Author: Tai An
- Categories: Changelog
- Canonical: https://www.agno.com/articles/strict-mode-tool-schemas-without-a-properties-field-no-longer-error
- Markdown: https://www.agno.com/articles/strict-mode-tool-schemas-without-a-properties-field-no-longer-error.md

`Function.process_schema_for_strict` no longer raises a `KeyError` when a tool schema leaves out the `properties` key. Strict mode now works for schemas registered verbatim, including MCP server schemas that don't include `properties`.