[bug] Google tool-schema sanitizer can emit array schemas without required items #5689

Client or integration

Direct HTTP/API client

Area

Tools / MCP / web search

Summary

The Google tool-schema sanitizer/compiler can emit a required array schema without an items schema. Some Google/Gemini tool-schema consumers reject or mishandle such arrays. Expected: when a required array lacks items, materialize a safe item schema during sanitization without changing valid existing item schemas.

Reproduction

1. Supply a tool/function schema containing a required property with type: "array" and no items.
2. Compile/sanitize it through the Google tool-schema path.
3. Inspect the emitted schema.
4. On official v2.63.0, the required array can remain without items.
5. A local patch materializes the missing array item schema and keeps valid schemas unchanged.

Version

2.63.0 / commit 96b1406

Operating system

Ubuntu Server Linux x86_64

Provider and model

Google/Gemini-compatible tool schema path

Logs or error output

Representative invalid shape: {"type":"array"} on a required tool parameter, with no "items".

Screenshots and supporting files

Focused Google schema/compiler regressions pass with the local patch.

Redacted configuration

{"type":"object","required":["values"],"properties":{"values":{"type":"array"}}}

Checks

• I searched existing issues and documentation.
• I removed secrets, tokens, account details, request credentials, and personal data.