You are using Claude Code to accelerate software development.

A concrete test case converts an imprecise correction into an executable success criterion. The input demonstrates the failing null-value condition, while the expected output defines exactly how the migration must handle it. Claude can modify the implementation, run the test, inspect the result, and continue iterating until the behavior passes.

Anthropic recommends giving Claude a verification mechanism such as a test suite, build result, linter, fixture comparison, or screenshot. Without such a mechanism, Claude can only judge that its output appears correct. A pass-or-fail test closes the feedback loop by allowing Claude to perform the work, evaluate the result, and refine it using objective evidence. ( https://code.claude.com/docs/en/best-practices )

Option A provides no additional specification and may generate a different but still incorrect implementation. Option B fixes the immediate defect manually but fails to use Claude’s iterative capabilities or establish a regression check. Option C supplies more description, but regenerating the entire script increases the risk of altering already-correct behavior and still lacks objective validation.

The best workflow is to add the failing case to the migration test suite, request the smallest necessary correction, run the relevant tests, and retain that test permanently to prevent the null-handling defect from recurring.

Official references/topics: Executable verification, test-driven iteration, regression protection, tight feedback loops.