Whether 'is tall' forms a verb phrase in 'Kim is tall' is a matter of basic linguistic definition and everyday syntactic analysis, requiring no citation.
The claim asks a basic, definitional question about the syntactic structure of a simple sentence ('Kim is tall'), where 'is' is a copular verb heading a verb phrase (or predicate phrase). This is a matter of basic linguistic definition and everyday grammatical observation (Common Knowledge under Step 0). Therefore, no citations are needed and the verdict is COMMON_KNOWLEDGE.