fix(tools): raise ToolUsageError instead of bare raise for non-dict arguments

[ashusnapx]

Summary

Fixes RuntimeError: No active exception to re-raise in ToolUsage._original_tool_calling() when _validate_tool_input returns a non-dict and raise_error=True.

Closes #6430

Problem

_original_tool_calling() at tool_usage.py:853 had a bare raise outside any except block:

if not isinstance(arguments, dict):
    if raise_error:
        raise   # <-- no active exception here
    return ToolUsageError(...)

When this path was hit with raise_error=True, Python raised RuntimeError: No active exception to re-raise instead of the intended ToolUsageError. The _tool_calling() fallback relies on catching a meaningful exception to trigger its retry logic, so this produced a confusing RuntimeError.

Also flagged by ruff check --select PLE0704.

Fix

Replace bare raise with explicit raise ToolUsageError(...):

if not isinstance(arguments, dict):
    if raise_error:
        raise ToolUsageError(
            f"{I18N_DEFAULT.errors('tool_arguments_error')}"
        )
    return ToolUsageError(f"{I18N_DEFAULT.errors('tool_arguments_error')}")

The except block above (line 846-848) correctly uses bare raise inside an active exception context — left unchanged.

Tests (4 new)

Test	What it verifies
test_original_tool_calling_non_dict_raises_tool_usage_error	raise_error=True raises ToolUsageError, not RuntimeError
test_original_tool_calling_non_dict_returns_error	raise_error=False returns ToolUsageError
test_tool_calling_fallback_on_non_dict	Full _tool_calling flow falls back gracefully
test_non_dict_raises_not_runtime_error	Exception type is ToolUsageError, not RuntimeError

All 32 tests in test_tool_usage.py pass. ruff check --select PLE0704 clean.

Verification

pytest lib/crewai/tests/tools/test_tool_usage.py -v
ruff check lib/crewai/src/crewai/tools/tool_usage.py --select PLE0704

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

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Run ID: 0897968b-51dc-485c-a47b-1ed42a99e3fe

📥 Commits

Reviewing files that changed from the base of the PR and between a395ea2 and ae7ebf9.

📒 Files selected for processing (2)

• lib/crewai/src/crewai/tools/tool_usage.py
• lib/crewai/tests/tools/test_tool_usage.py

🚧 Files skipped from review as they are similar to previous changes (2)

• lib/crewai/src/crewai/tools/tool_usage.py
• lib/crewai/tests/tools/test_tool_usage.py

---

📝 Walkthrough

Walkthrough

ToolUsage._original_tool_calling now consistently raises or returns a localized ToolUsageError for tool-argument validation failures and non-dict parsed input. Regression tests cover direct calls, fallback behavior, and prevention of RuntimeError.

Changes

Bare Raise Fix

Layer / File(s)	Summary
Raise ToolUsageError for invalid arguments lib/crewai/src/crewai/tools/tool_usage.py	_original_tool_calling reuses a localized ToolUsageError for validation failures and non-dict parsed input, raising or returning it according to raise_error.
Regression tests for non-dict input lib/crewai/tests/tools/test_tool_usage.py	Adds a minimal ToolUsage helper and tests for raised, returned, and fallback ToolUsageError behavior instead of RuntimeError.

Estimated code review effort: 2 (Simple) | ~10 minutes

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 62.50% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	Title clearly describes the fix for non-dict tool arguments and is specific to the main code change.
Description check	✅ Passed	The description matches the code change and regression tests for the ToolUsage error path.
Linked Issues check	✅ Passed	The PR addresses #6430 by replacing the bare raise, preserving fallback behavior, and adding regression tests.
Out of Scope Changes check	✅ Passed	The changes are limited to the targeted bug fix in tool_usage.py and matching tests, with no unrelated additions.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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[ErenAta16]

Same one-line fix as #6486, #6512, #6511, #6499 — this is one of five open PRs (added this one to the tally) independently fixing the same bare-raise-outside-except bug in _original_tool_calling. Reproduced the bug standalone: the bare raise here raises RuntimeError: No active exception to reraise rather than the intended ToolUsageError, since it is outside any except block. This PR's fix is correct and equivalent to the others. Left a fuller comparison on #6486, which constructs the error once and reuses it for both branches rather than twice — noting the duplication here so only one lands.

[ashusnapx]

Fixed — error is now constructed once and reused for both branches (raise and return), matching the approach in #6486. Thanks for the catch.

[ErenAta16]

Confirmed - the current diff constructs tool_arguments_error once before the try block and both the raise and the return paths reuse the same instance now. That's the same shape as #6486, so this fix is correct.

[ashusnapx]

Thanks for confirming. Ready for maintainer review.