The data type of the field. UUID and ENUM are first-class types, so no separate boolean flags are needed.
enum_values
string
repeated
If type is FILTER_FIELD_TYPE_ENUM, these are the valid string values.
description
string
Human-readable description of the field (e.g., “When the run was created”).
display_name
string
Human-friendly display name (e.g., “Asset Name” for field_name “asset_name”).
operators
string
repeated
CEL infix operator tokens valid for this field, e.g. ”==”, “in”. Usually the default set for the field’s type, but narrower when the field restricts it. Display copy for each token comes from FilterGrammarService.
functions
string
repeated
CEL member function names valid for this field, e.g. “contains”, “getFullYear”. Display copy for each name comes from FilterGrammarService.
nullable
bool
optional
Whether the field can compare against null. For a metadata key this is true: a key that is not set on an entity reads as null, so field == null matches entities missing the key and field != null matches those that have it. (There is no separate “set but null” state, since an assigned metadata value always holds a concrete value.) Optional so that an unset value means “unknown” rather than implicitly “not nullable”.
