Pull Request Checklist

Before submitting, make sure you've checked the following:

• Linked Issue/Discussion: Relates to issue: Builtin tool functions crash with TypeError when models pass numeric parameters as strings via native function calling. #25641
• Target branch: The pull request targets the dev branch.
• Description: A concise description of the changes is provided below.
• Changelog: A changelog entry following Keep a Changelog format is included below.
• Documentation: No documentation changes required.
• Dependencies: No new or updated dependencies.
• Testing: Manual verification performed (see below).
• No Unchecked AI Code: This PR has undergone human review and manual testing.
• Self-Review: A self-review of the code has been performed.
• Architecture: Smart default behaviour; no new settings introduced.
• Git Hygiene: The PR is atomic, rebased on dev, and contains no unrelated commits.
• Title Prefix: fix

Changelog Entry

Description

Models using native function calling (function_calling: native) sometimes emit numeric or boolean tool parameters as strings — e.g. count="1" instead of count=1. The builtin tools declare int/Optional[int]/bool/float type hints but never coerced the actual runtime values, so the first comparison or arithmetic on such a value raised:

TypeError: '<' not supported between instances of 'int' and 'str'

For example, search_web crashes on count = max(1, min(count, max_count)) (builtin.py), so the model receives an error response instead of search results.

Fix: coerce string-valued arguments to their declared scalar type inside the shared tool wrapper get_async_tool_function_and_apply_extra_params (backend/open_webui/utils/tools.py). Because every builtin and user-defined tool is invoked through this wrapper, the fix is centralized rather than scattered across individual tools.

The coercion is best-effort and non-intrusive:

• Only str values are touched; values that already have the correct type are left untouched.
• int / float / bool (and their Optional[...] forms) are supported. int also tolerates integral floats like "1.0".
• Booleans accept the usual true/false/1/0/yes/no/on/off spellings.
• Unparseable values (e.g. count="abc") are passed through unchanged, preserving existing behaviour.
• get_type_hints failures fall back to no coercion.

Fixed

• Builtin tool functions no longer crash with TypeError when a model passes numeric/boolean parameters as strings via native function calling (e.g. search_web(count="1")).

Additional Information

• No new dependencies added.
• No behavioral change when tools receive correctly-typed arguments — purely defensive coercion for string inputs.

Manual Verification Performed

Validated the coercion against representative tool signatures (search_web(query: str, count: Optional[int]), and a tool with bool/float/int params):

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