Coding agents write a new helper instead of finding the one you already have

Coding agents often create new helper functions, like for formatting dates or parsing prices, even when existing, well-tested utilities (e.g., "formatDate" in "src/utils") are already available in the repository. This can lead to redundant code and neglect of previously implemented fixes, such as a timezone correction. Providing clear instructions to the agent, specifying the location of shared utilities (e.g., "date and money helpers are in src/utils, API wrappers in src/api"), can mitigate this issue. This behavior is also observed in AI chat interfaces like ChatGPT or Claude.

Unlike prior discussions on AI code generation, this report highlights the agents' tendency to create redundant helper functions instead of reusing existing, tested utilities.