known-encoding

Id

@azure-tools/typespec-azure-core/known-encoding

Check for supported encodings.

Check that @encode uses a supported encoding for Azure services.

Known supported encodings:

Target type	Supported encodings
utcDateTime / offsetDateTime	rfc3339, rfc7231, unixTimestamp
duration	ISO8601, seconds
bytes	base64, base64url

Impact

• Area: API, SDK

Non-standard formats are transmitted as the raw, unencoded wire type, which hurts API and SDK usability.

LintDiff Equivalent

This rule corresponds to the LintDiff rule ValidFormats.

❌ Incorrect

Unknown encoding on a model property:

model Foo {
  @encode("custom-rfc")
  myDateTime: utcDateTime;
}

Unknown encoding on a scalar:

@encode("custom-rfc")
scalar myDateTime extends utcDateTime;

✅ Correct

Known encoding on a model property:

model Foo {
  @encode("rfc3339")
  myDateTime: utcDateTime;
}

Known encoding on a scalar:

@encode("rfc3339")
scalar myDateTime extends utcDateTime;

Suppression

Suppress only when required to match an existing API; otherwise use a standard format, encoding, or type.