<p>The plot scale represents an undertheorized domain in urban design, positioned between citywide structure and street-level interfaces. Although classic urban design theories have long emphasized spatial configuration as shaping urban vitality, the plot itself has rarely been treated as a configurational unit. This study addresses that gap by conceptualizing the plot as a meso-scale spatial configuration. It proposes a typology of plot-scale spatial layouts, including edge-distributed, center-oriented, and street-integrated types, and introduces a multidimensional vitality metric comprising activity density, diversity, and willingness. Based on behavioral observation and spatial analysis of 12 commercial plots in Shanghai, the study found that center-oriented and street-integrated layouts were associated with higher levels of urban vitality than edge-distributed configurations. Two spatial characteristics, building permeability and spatial amenity diversity, correlated with distinct vitality dimensions. These findings suggest that the link between spatial layout and urban vitality operates through intermediate spatial conditions that relate configurational properties to observable activity patterns. Given the limited sample size and the context-specific nature of the data, the results are best understood as exploratory. This study provides an exploratory conceptual framework for interpreting plot-scale vitality and contributes to configurational urban morphology by extending analysis to the internal spatial organization of plots.</p>