Storage

The pluggable persistence layer.

behest defines four store traits plus a RunStore trait, each with multiple feature-gated backends. A RuntimeStore facade composes them into a single handle for the runtime.

Trait matrix

Trait	Purpose	Key methods
SessionStore	Session CRUD + message history	create_session, append_message, list_messages, get_latest_compaction
EmbeddingStore	Vector persistence + search	upsert, search, delete_by_session
ExecutionStore	Tool execution + token usage + session stats	record_execution, record_usage, session_stats
ArtifactStore	Binary file storage	put, get, list_by_session
RunStore	Event-sourced run lifecycle	create_run, append_event, list_events, get_run_state

Backend matrix

Backend	Session	Embedding	Execution	Artifact	Run	Feature
Memory	✓	✓	✓	✓	✓	(default)
Redis	✓	—	—	—	—	redis
SQLx PostgreSQL	✓	—	—	—	—	sqlx-postgres
SQLx MySQL	✓	—	—	—	—	sqlx-mysql
SQLx SQLite	✓	—	—	—	—	sqlx-sqlite
MongoDB	✓	—	—	—	—	mongodb
SurrealDB	✓	—	—	—	—	surrealdb
Qdrant	—	✓	—	—	—	qdrant
Object (S3/Disk)	—	—	—	✓	—	object_store

RuntimeStore facade

RuntimeStore composes the individual stores into a single handle. The runtime accesses stores by name through the Extensions facade:

pub struct RuntimeStore {
    session: Arc<ExtensionPoint<dyn SessionStore>>,
    execution: Arc<ExtensionPoint<dyn ExecutionStore>>,
    run: Arc<ExtensionPoint<dyn RunStore>>,
    embedding: Option<Arc<ExtensionPoint<dyn EmbeddingStore>>>,
    artifact: Option<Arc<ExtensionPoint<dyn ArtifactStore>>>,
}

impl RuntimeStore {
    pub fn from_extensions(ext: &Extensions) -> Self;
    pub fn session(&self, name: &str) -> Option<Arc<dyn SessionStore>>;
    pub fn execution(&self, name: &str) -> Option<Arc<dyn ExecutionStore>>;
    pub fn run(&self, name: &str) -> Option<Arc<dyn RunStore>>;
}

See also

• SessionStore — the session trait.
• EmbeddingStore — the vector trait.
• ExecutionStore — the execution trait.
• ArtifactStore — the artifact trait.
• RunStore — the run trait.
• RuntimeStore — the facade.