システムプロンプトの実装

crates/session-store/src/lib.rs

@@ -35,9 +35,9 @@ pub mod store;
 pub use event_trace::TraceEntry;
 pub use fs_store::FsStore;
 pub use session::{
-    SessionStartState, create_compacted_session, create_session, ensure_head_or_fork, fork,
-    fork_at, restore, save_cache_locked, save_cache_unlocked, save_config_changed, save_delta,
-    save_outcome, save_turn_end, save_usage,
+    SessionStartState, create_compacted_session, create_session, create_session_with_id,
+    ensure_head_or_fork, fork, fork_at, restore, save_cache_locked, save_cache_unlocked,
+    save_config_changed, save_delta, save_outcome, save_turn_end, save_usage,
 };
 pub use session_log::{
     EntryHash, HashedEntry, LogEntry, Outcome, RestoredState, SessionOrigin, UsageRecord,

crates/session-store/src/session.rs

@@ -25,6 +25,20 @@ pub async fn create_session(
     state: SessionStartState<'_>,
 ) -> Result<(SessionId, EntryHash), StoreError> {
     let session_id = crate::new_session_id();
+    let hash = create_session_with_id(store, session_id, state).await?;
+    Ok((session_id, hash))
+}
+
+/// Write a fresh `SessionStart` entry using a pre-generated session ID.
+///
+/// Used by callers that need to reserve a session ID synchronously but
+/// defer the initial log append (e.g. Pod, which resolves a templated
+/// system prompt only at first turn). Returns the resulting head hash.
+pub async fn create_session_with_id(
+    store: &impl Store,
+    session_id: SessionId,
+    state: SessionStartState<'_>,
+) -> Result<EntryHash, StoreError> {
     let entry = LogEntry::SessionStart {
         ts: session_log::now_millis(),
         system_prompt: state.system_prompt.map(String::from),
@@ -40,7 +54,7 @@ pub async fn create_session(
         entry,
     };
     store.append(session_id, &hashed_entry).await?;
-    Ok((session_id, hash))
+    Ok(hash)
 }
 
 /// Create a compacted session from an existing one.