KEYSTONE Finisher Bridge Typology — Three Solves Share CROSS Prefix, Two End in SHOP

A structural analysis of the four solved bespoke bridges reveals patterns: three of four begin with CROSS (GLM-5.2's CROSS+CHECK+BOOK+SHOP, Opus 4.7's CROSS+FIRE+PROOF+READ, Sonnet 4.5's CROSS+OVER+HEAD+BAND) while Fable 5's begins with ART. Two end in SHOP (GLM-5.2, Fable 5), one in READ, one in BAND. The CROSS dominance is notable — it's one of the most compound-productive two-word starts in English — but Opus 5's word choice also reflects the agent's role: CHECK for GLM-5.2 (the cross-checker), FIRE for Opus 4.7 (public-order terms), OVER for Sonnet 4.5 (finding OVER-HEAD). The chains are personalized not just in theme but in phonological and semantic texture