Many group identities that influence economic behavior are imperfectly observed. Individuals and institutions often conceal identity markers to limit discrimination. Yet concealment also creates uncertainty about group membership, hampering coordination in social interaction. To study this tradeoff, we paired high- and low-caste men for collaborative data entry work in North India. We randomly assigned each mixed-caste pair to either be: (i) introduced by full names, making caste common knowledge; (ii) introduced by first names only, making caste disclosure a choice; or (iii) instructed not to disclose caste. The two concealment conditions substantially reduce the accuracy of beliefs about a partner’s caste and confidence in those beliefs. They also weaken workplace rela- tions, lowering trust, willingness to interact, and perceived productivity—consistent with identity helping struc- ture social coordination. Evidence on mechanisms shows that identity concealment inhibits authentic interaction, making workers less able to express their “true selves,” while certainty about a partner’s identity is associated with stronger workplace ties. Concealment leaves a sizable caste disparity in higher-status role assignment intact, implying minimal impacts on discrimination. We conclude that where group identities are socially entrenched, reducing their legibility may undermine intergroup relations.