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Topic
Boundary Validation
Checking untrusted input and output at system boundaries while keeping internal flows clear.
2 pages
Writing25 September 2026
Intentional Model Design
A model should express required fields, genuine absence, and distinct variants in its type. Python unions and C# records encode those promises, while boundaries check external values.
Writing20 December 2020
Validating Formal Arguments? No Thank You!
Validate and clean data at the front and back doors; skip checks on internal formal arguments. Immutable DTOs preserve trust, one exception reports all errors, and black box tests exercise the doors.