Feature Flags

Heartbit uses Cargo feature flags to control which capabilities are compiled in. This keeps the binary small when you only need core functionality and allows opting in to heavier dependencies.

Feature Reference

Feature	Dependencies	What it enables
core (default)	—	Agent runner, orchestrator, LLM providers, tools, memory, config
kafka	rdkafka	Kafka consumer/producer
daemon	kafka + cron, prometheus	Daemon with HTTP API, cron scheduling, metrics
sensor	daemon + quick-xml, hmac	7 sensor sources (RSS, Email/JMAP, Webhook, Weather, Audio, Image, MCP), triage, story correlation
restate	restate-sdk 0.8	Durable workflow execution via Restate
postgres	sqlx, pgvector	PostgreSQL memory store and task store
a2a	a2a-sdk	Agent-to-Agent protocol support
telegram	teloxide	Telegram bot integration for daemon mode
local-embedding	fastembed	Local ONNX embeddings via fastembed (no API keys required)
full	all above (except local-embedding)	Everything

Dependency Graph

core (default)
  |
  +-- kafka (rdkafka)
  |     |
  |     +-- daemon (+ cron, prometheus)
  |           |
  |           +-- sensor (+ quick-xml, hmac)
  |
  +-- restate (restate-sdk)
  +-- postgres (sqlx, pgvector)
  +-- a2a (a2a-sdk)
  +-- telegram (teloxide)
  +-- local-embedding (fastembed)

full = kafka + daemon + sensor + restate + postgres + a2a + telegram

Note that local-embedding is excluded from full because fastembed pulls in ONNX Runtime which significantly increases binary size. Enable it explicitly when needed.

Usage

As a library

# Core only (default)
cargo add heartbit

# With specific features
cargo add heartbit --features postgres,local-embedding

# Everything
cargo add heartbit --features full

In Cargo.toml

[dependencies]
heartbit = { version = "*", features = ["daemon", "postgres"] }

Building from source

# Default (core only)
cargo build -p heartbit-cli

# With daemon and Telegram
cargo build -p heartbit-cli --features daemon,telegram

# Full build
cargo build -p heartbit-cli --features full

Build Prerequisites

Some features require system libraries:

Feature	System dependencies
kafka / daemon / sensor	cmake, libssl-dev, pkg-config (for rdkafka)
local-embedding	ONNX Runtime (bundled by fastembed)
postgres	PostgreSQL client libraries