Feature Flags

behest follows the additive-only feature flag policy: every feature is off unless explicitly enabled, and removing a feature is a breaking change. Pick the smallest set of features that covers your use case; the default feature is tls-rustls and nothing else.

Naming conventions

• Library features are named after the underlying dependency: redis, nats, qdrant, mongodb, surrealdb, openai, anthropic.
• TLS stacks are mutually exclusive: tls-rustls (default) or tls-native. Switching requires an explicit opt-out of the default.
• Aggregator features turn on a coherent bundle: full, storage-all, rag-all, queue-all.

Default

Feature	Description
tls-rustls	Default TLS stack. Pulls in rustls for HTTP clients and any TLS-using backends.

Provider adapters

Feature	Description
openai	The OpenAI-compatible chat and embedding adapters (OpenAiChatAdapter, OpenAiEmbeddingAdapter). Also enables the provider.openai.* factory kinds.
anthropic	The Anthropic Messages API chat adapter (AnthropicChatAdapter). Also enables the provider.anthropic.chat factory kind.

Storage backends

Feature	Description
redis	Redis-backed store support; also enables RedisRuntimeEventStore, RedisRuntimeStreamAdapter, and RedisSessionDataStore.
redis-cluster	Redis Cluster support; implies redis.
sqlx-postgres	SQLx PostgreSQL store backend.
sqlx-mysql	SQLx MySQL store backend.
sqlx-sqlite	SQLx SQLite store backend.
mongodb	MongoDB session store backend.
surrealdb	SurrealDB session store backend.
object_store	Object storage backend (AWS S3 compatible) for ArtifactStore.
storage-all	Enables redis + sqlx-postgres + sqlx-mysql + sqlx-sqlite + mongodb + surrealdb. Intentionally does not enable object_store.

RAG

Feature	Description
rag	Core RAG context adapter (no extra deps). Enables the rag module.
qdrant	Qdrant vector store backend for embeddings.
tantivy	Tantivy full-text backend.
rag-all	Enables rag + qdrant + tantivy.

Queues

Feature	Description
queue	Core EventPublisher trait; enables the queue module.
nats	NATS JetStream publisher.
queue-all	Enables queue + nats + redis.

Observability

Feature	Description
otel	OpenTelemetry tracing integration.

Aggregator

Feature	Description
full	An opinionated full profile: openai + anthropic + redis + redis-cluster + nats + sqlx-postgres + mongodb + surrealdb + otel + rag-all + queue-all + object_store. Intentionally does not enable sqlx-mysql or sqlx-sqlite.

Selection guide

The matrix below maps common use cases to a feature set. Add more only when needed.

Use case	Feature set
Local exploration, no network	(no extra features beyond tls-rustls)
OpenAI chat only	openai
OpenAI chat + embeddings	openai
Multi-provider	openai + anthropic
Production with sessions in Postgres	sqlx-postgres
Production with sessions in MongoDB	mongodb
Event publishing through NATS	queue + nats
RAG over a vector store	rag + qdrant
Distributed event log	redis or nats + otel
Full demo / self-contained showcase	full

Mutually exclusive combinations

Only one TLS stack at a time:

behest = { version = "0.4", default-features = false, features = ["tls-native", "openai", "redis"] }

Do not enable tls-rustls together with tls-native; the build will fail with a duplicate-dependency error.

Cargo metadata

To inspect the resolved feature set:

cargo tree -p behest -e features --features full

This prints the full feature graph as it would be activated with --features full, showing which dependencies are pulled in by which feature.