A question identity is unset until a run establishes it. Testing whether the
record exists cannot stand in for that: a host with no state to send seeds a
default record, and a default record is truthy, so a resumption missing its real
state would have proceeded as question zero.
Every way of recording a message count now refuses one behind what is already
stored, through one shared check: a new identity, an evidence outcome and a
declaration, each against the newest identity, evidence epoch and declaration
epoch. Identities and epochs are only comparable while the conversation grows,
and `before_model_request` results are assigned back onto history, so that is a
constraint on the host rather than a guarantee of the framework. Left unchecked,
an evidence outcome moving backwards freezes every later declaration as stale,
and a declaration moving backwards replaces a newer one with an older one and
revives the answer it grounded.
The searches, citations and executions of a question in progress survive a
resumption. Clearing them cost the results the model was still answering from: a
citation afterwards recorded no provenance and could not resolve against the
expanded result it had seen, falling through to a database lookup.
A code execution counts as evidence when it succeeded or printed something. A
raised error with an empty stdout grounds nothing.