gather asks the machines side by side, and the test's stand-in call wrote one map from each of them: a concurrent map write, the panic once seen at compositioninputs_test.go:61 (the race detector shows it every run). The record is guarded; the whole assigner's unit suite runs clean under the race detector. Builds: design 47 G §354, A-243, A-252 Claude-Session: https://claude.ai/code/session_01NcbgfGKaxw984XyAPfLm4h