Definition. Persistent event stream [ftip-00C7]
Definition. Persistent event stream [ftip-00C7]
Fix a finite event alphabet \(\mathcal E_{\rm har}\). A persistent event stream of length \(n\) is
\[ L_n=(e_0,\ldots ,e_{n-1})\in \mathcal E_{\rm har}^{n}. \]The append operation is \(L_{n+1}=\operatorname {append}(L_n,e_n)\). Write \(L_i\preceq _{\rm pref}L_j\) when \(L_i\) is a prefix of \(L_j\). An append-only stream satisfies \(L_i\preceq _{\rm pref}L_j\) for every \(i\leq j\); branching creates distinct continuations with a common prefix rather than rewriting that prefix.
Events may record model or tool calls, messages, interventions, retries, verifier outcomes, harness edits, and resource use. The event schema and its exact version belong to the configuration of Definition [ftip-00C6].