What diagnosis fits a child who avoids eye contact, shows limited social interaction, and plays in a mechanical way?

The characteristics described in the question—avoiding eye contact, demonstrating limited social interaction, and engaging in mechanical play—are highly indicative of autism spectrum disorder (ASD). Children with autism often struggle with social communication and interaction, which is reflected in their difficulty maintaining eye contact and their tendency to play in ways that may seem repetitive or focused on the mechanics of objects rather than imaginative play.

In contrast, while social phobia might lead to avoidance of social situations, it does not typically manifest as a mechanical style of play or the same level of restricted social interaction as seen in autism. Generalized anxiety disorder is characterized by excessive worry and anxiety across various situations and does not specifically correlate with the behavioral patterns described. Finally, attachment disorders relate more to the relationship a child has formed with their caregivers and do not necessarily lead to the same specific patterns of social interaction and play seen in autism. Thus, the combination of symptoms clearly aligns with the autism diagnosis.