fix(tools): replace bare raise with ToolUsageError in _original_tool_calling

[molinto]

Fixes #6430

Problem

ToolUsage._original_tool_calling() contains a bare raise outside any except block:

if not isinstance(arguments, dict):
    if raise_error:
        raise   # <- no active exception here
    return ToolUsageError(f"{I18N_DEFAULT.errors('tool_arguments_error')}")

A bare raise re-raises the exception currently being handled. On this path no exception is active (the preceding try/except completed normally), so if _validate_tool_input ever returns a non-dict, Python raises RuntimeError: No active exception to re-raise instead of the intended tool-arguments error.

Today _validate_tool_input always returns a dict or raises, so the branch is a latent landmine rather than a hot path — but _tool_calling() calls this with raise_error=True and relies on catching a meaningful exception to trigger its fallback, so any future change or subclass of _validate_tool_input would surface this as a confusing RuntimeError.

ruff check --select PLE0704 also flags this line. (It flags one more bare raise in crewai/agent/core.py:660; that one is only ever reached from within an exception context via _handle_execution_error, so it behaves correctly at runtime — left untouched here.)

Fix

Raise ToolUsageError (an Exception subclass) with the same i18n message the non-raising branch returns, keeping both branches consistent.

Tests

Added a regression test in lib/crewai/tests/tools/test_tool_usage.py that forces _validate_tool_input to return a non-dict and asserts ToolUsageError is raised (previously: RuntimeError). Verified failing-without / passing-with the fix. ruff clean on the touched file.

Note for maintainers

This contribution was made with AI assistance. Per CONTRIBUTING.md the llm-generated label is required — I don't have triage permission to set it, so could a maintainer please add it?

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro Plus

Run ID: fd77308b-1df8-476f-a453-127e0dd3e202

📥 Commits

Reviewing files that changed from the base of the PR and between 559a9c6 and bd79e34.

📒 Files selected for processing (3)

• fix-bare-raise-tool-usage.patch
• lib/crewai/src/crewai/tools/tool_usage.py
• lib/crewai/tests/tools/test_tool_usage.py

👮 Files not reviewed due to content moderation or server errors (3)

• lib/crewai/tests/tools/test_tool_usage.py
• lib/crewai/src/crewai/tools/tool_usage.py
• fix-bare-raise-tool-usage.patch

---

📝 Walkthrough

[!WARNING]

Walkthrough skipped

File diffs could not be summarized.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

---

Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out.

❤️ Share

• X
• Mastodon
• Reddit
• LinkedIn

_{Comment @coderabbitai help to get the list of available commands.}