Module session 

Session persistence for LLM conversation histories.

A session is an append-only log of SessionEntry records — finalized chat Messages and non-destructive SessionEntry::Compaction markers — identified by a SessionMeta header. Two SessionStore implementations are provided: InMemorySessionStore (non-persistent) and JsonlSessionStore (one JSONL file per session on disk). build_context converts a stored entry log into the message list to send to an LLM, honoring the most recent compaction.

Ownership and lifetime

A SessionStore is owned by the component that creates it — typically a single agent instance — and lives exactly as long as its owner. There is no global registry and no static state; dropping the owner drops the store (persisted JSONL files of course remain on disk).

Invariants

1. Only finalized messages reach the store. Callers must append only messages with streaming == false; partial streaming emissions and their id-based dedup/replacement stay in the caller’s memory.
2. The store API is append-only. No delete, update, or overwrite operations exist. Compaction is recorded as a new entry that changes how the context is built, never by rewriting history. A crash can lose at most the single in-flight entry (appends flush immediately).

Structs

InMemorySessionStore

Non-persistent SessionStore holding all sessions in memory.

JsonlSessionStore

Persistent SessionStore writing one JSONL file per session.

SessionMeta

Header metadata identifying one session.

Enums

SessionEntry

One record in a session’s append-only log.

Traits

SessionStore

Append-only storage for session logs.

Functions

build_context

Builds the LLM context from a session’s entry log.