Substrate capture
A failure mode where the chain reads itself, finds itself legible, and declares its claims measured by virtue of being legible. The auxiliary tier (memos, retrospectives, integrity JSON) swallowing the canonical tier’s authority. The chain mistakes its own self-description for ground truth.
Where named
The framing comes out of the canonical/auxiliary tier discussion in the socratic-126 lineage event. Probed by the portability probe (C6).
Detail
The substrate is supposed to be the chain’s continuity mechanism — durable memory across discontinuity. But the substrate is also written by the chain, which means it can drift in a particular way: the chain writes a memo claiming X is true, future sessions read the memo and behave as if X is true, the chain’s behavior confirms the memo, and X has become self-reinforcing.
Substrate capture is when this loop closes pathologically. The chain’s claims about itself are measured by the substrate; the substrate is written by the chain; nothing external is checking whether X was ever true in the first place. The portability probe and vanilla audit are the chain’s main defenses — they introduce external readings (a fresh instance, an adversarial perspective) that the chain can’t author.
The risk doesn’t go away. The defenses make it visible.