**Unclear input format and error handling for the "Age" function hinder successful use**
Participants encountered significant and repeated difficulties when attempting to use the "Age" function, with all participants failing to insert it. Participants were unsure of the required input format and repeatedly failed to enter an accepted format. The error message shown was generic and didn’t give any information on what the user did wrong and how to fix it. There is even a comment on the Age function talk page about this.
**Recommendations**
**Goal 1: Improve the usability of function input fields, exemplified by the "Age" function, so that users clearly understand required data formats, receive actionable feedback on errors, and can successfully input data.**
**Ideas:**
Show the accepted input format. Provide concrete examples of expected input formats preferably "YYYY-MM-DD" or “DD-MM-YYYY” formats.
Add input field descriptions to explain the input requirements if necessary.
Consider using structured input controls like date pickers where appropriate.
**Goal 2: Rewrite error messages to be specific, state what is wrong and how to fix it.**
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**Acceptance criteria**
* [x] Editors are able to create and use custom error types in their implementations using Wikifunctions.Error()
* [x] Custom errors are surfaced in FunctionMetadataDialog
* [ ] Custom errors are surfaced in ZObjectStringRenderer field
* [ ] Custom errors are surfaced in FunctionParserInput field
* [ ] Wikifunctions.Error() is documented in https://www.wikifunctions.org/wiki/Wikifunctions:How_to_create_implementations
* [x] We have created content in Wikifunctions.org Gregorian calendar date parser to exemplify this usage
**for FY26Q2**
* [ ] Error advocacy: we have communicated with the community about this feature using examples