Variable: TRANSFORM_HASH_PREFIX

const TRANSFORM_HASH_PREFIX: "chain-v1:" = 'chain-v1:'

Defined in: src/lib/time-travel/receipt.ts:754

The prefix a chained Receipt.cache.transformHash carries — the NAME of the scheme that produced it, inside the value, so a verifier can tell the two schemes apart without a second field:

• 'chain-v1:<16 hex>' — transformHashOf: each message of the returned request digested on its own and chained in order, then the rest of the request. Minted since this prefix existed.
• a bare <16 hex> — the older WHOLE-REQUEST scheme, receiptHash(runId, stableJson(request)). Every receipt minted before the prefix carries this form, and it still verifies with that formula.

WHY THE SCHEME CHANGED. The whole-request digest could not be extended: the strategy's markers sort to the front of the canonical JSON and move on every call, so call k's preimage shared no prefix with call k−1's and every byte of the history was hashed again — measured, the larger half of the receipt's SHA-256 input under a caching provider. A chain over per-message digests is extended by the messages a call added and nothing else.