Author validation rules for Flet Python control properties using Annotated V rules.
npx skills add https://github.com/flet-dev/flet --skill flet-validation
Please help me install this Agent Skill. Skill: flet-validation Source: https://github.com/flet-dev/flet/tree/main/.agents/skills/flet-validation Command: npx skills add https://github.com/flet-dev/flet --skill flet-validation
Adding validation to Flet Python controls requires choosing between field-level Annotated rules, class-level validation_rules, and before_update() checks, while keeping docstrings, tests, and Dart-side behavior consistent. This Skill provides the conventions and decision order to do that correctly.
Ask the AI to add validation to a Flet control property, for example to enforce that a slider's value stays between its min and max using V rules with matching docstrings and tests.
High-intent search queries and answers about installing and using this skill.
Add field-level rules with Annotated[..., V.*] metadata on the dataclass field, such as V.between(0.0, 1.0) for bounded numbers. Use __validation_rules__ only for cross-field invariants that field rules cannot express cleanly.
Reserve before_update() for normalization and mutation, or for invariants genuinely not expressible with existing V.* primitives. Never duplicate the same invariant in both before_update() and V rules.
Use field comparison rules V.gt_field, V.ge_field, V.lt_field, and V.le_field referencing the other field by name. If either side is optional and currently None, the comparison is skipped.
Add one ValueError entry per logical rule in the property docstring, starting with 'If it ...' and using canonical wording from the V.* helpers in flet/utils/validation.py. For V.between, use a single inclusive-bounds entry.
Yes. Review the Flet Dart wrapper and the underlying Flutter widget assertions, then mirror those constraints in Python so invalid values fail before crossing to Dart, including Dart-applied defaults.
Cover one valid and one invalid case per logical rule, boundary values, cross-field set/unset combinations for optional values, and effective-default behavior. Place runtime tests in sdk/python/packages/flet/tests/test_validation.py.
wildbitcaEnforce Dart type safety, immutability, and widget composition standards in Flutter projects.
flet-devExecute Python Flet framework unit tests using pytest.
bactopiaValidate .claude/docs reference documentation for staleness and drift with bactopia-docs --validate.
pgagarinovEnforce Python API coding conventions for the BookStore project.
