https://developers.openai.com/api/docs/guides/function-calling?api-mode=responses#strict-mode

If strict is omitted (like we did previously), the Responses API will
try to transform the schema to a strict one, that means that all fields
will be marked as required. This was causing issues with the Linear MCP
server's `list_issues`, as the model always specified both `query` and
`customView`, but they can only be used exclusively.

Release Notes:

- agent: Fixed issues when OpenAI models call tools from MCP servers
with optional fields

Co-authored-by: Gaauwe Rombouts <mail@grombouts.nl>