Send the delta, not the transcript

The lazy way to move context between two coding agents is to copy the whole conversation. It is also the wrong way. A transcript is large, it repeats what the target already knows, and it buries the two sentences that matter.

context-bridge keeps a small knownBy matrix: for every pair of agents, how far into each agent's stream the other one has been told. A handoff sends only the missing part, in four bounded sections: Conversation, Decisions, Work, Next. The receiving agent spends one short sentence acknowledging it. That is the entire overhead.

Reconciliation is my day job, and those systems do not resend the ledger. They send the diff since the last watermark. Agent handoff has the same shape.