baikai-effectful

A thin, policy-free effectful binding over baikai's transport. It exposes one dynamic effect, Baikai, whose operations mirror baikai's transport functions, plus interpreters that run those operations against a real or isolated provider registry.

It is the seam, not the framework: it adds no retries, backoff, rate limiting, budgets, caching, or error remapping. Failures propagate exactly as baikai produces them — the blocking path throws Baikai.Error.BaikaiError; the streaming paths surface baikai's terminal EventError event in-band. Policy belongs one layer up, written in terms of this effect.

The effect

data Baikai :: Effect where
  Complete      :: Model -> Context -> Options -> Baikai m Response
  StreamCollect :: Model -> Context -> Options -> Baikai m [AssistantMessageEvent]
  StreamEach    :: Model -> Context -> Options -> (AssistantMessageEvent -> m ()) -> Baikai m ()

Operations

streamEach preserves incrementality (the callback sees events as they arrive); a terminal EventError appears in-band rather than as a thrown exception, matching baikai.

Interpreters

runBaikai     :: (IOE :> es) => Eff (Baikai : es) a -> Eff es a                       -- global registry
runBaikaiWith :: (IOE :> es) => ProviderRegistry -> Eff (Baikai : es) a -> Eff es a   -- explicit registry

The operations are registry-agnostic; the interpreter picks the registry, mirroring baikai's own completeRequest vs completeRequestWith split. Because Baikai is a dynamic effect, you can re-interpret the same operations — stub them in tests, record/replay, intercept, or (one layer up) wrap them with retries/caching/tracing — without touching any call site.

Example

import Baikai.Effectful
import Effectful (Eff, runEff)

describe :: (Baikai :> es) => Model -> Context -> Options -> Eff es Response
describe = complete

main :: IO ()
main = do
  -- against baikai's process-global registry (providers registered elsewhere):
  r <- runEff . runBaikai $ describe model ctx opts
  print r

For a hermetic test, register a stub provider in an isolated registry with Baikai.Provider.Registry.newProviderRegistry / registerApiProviderWith and drive the operations through runEff . runBaikaiWith reg. See test/ in this package.

Live demo

The test suite includes a live, network-touching demo gated on an environment variable, so the default run stays hermetic:

# hermetic (default): no network, no key — the live case prints a skip line and passes
cabal test baikai-effectful-test

# live: registers the OpenAI provider and makes one real call
BAIKAI_EFFECTFUL_LIVE=1 OPENAI_API_KEY=sk-... cabal test baikai-effectful-test

Why a separate package

The core baikai package deliberately carries no effectful dependency, and most baikai users do not use effectful. Shipping the binding as its own artifact keeps the core dependency-light while giving any effectful program a reusable baikai↔effectful seam — the same way baikai-claude / baikai-openai layer on baikai.