Deck

Deck is the single composition root for your entire application.

Creating a Deck

from agentdeck import Deck, Agent

deck = Deck(
    agents=[Agent(name="bot", instructions="Help user.")],
)

Or discover components automatically from ./.agentdeck/:

deck = Deck.from_project()

What Deck is responsible for

You own intent: which agents, tools, workflows and skills exist, and what they do. Deck owns the machinery underneath them.

Deck is responsible for	you never wire it yourself
run identity	every run gets a durable id, a namespace, and an optional key of your choosing
execution lifecycle	starting, suspending, resuming and cancelling, and the rules for which of those a run will accept right now
persistence	the event log, and the session a conversation accumulates in
event streams	one canonical stream per run, replayable and tailable, whichever process is executing it
concurrency	one turn per session, settled atomically, so two servers cannot both answer the same conversation

That split is the reason a Deck takes declarations rather than infrastructure: an agent says what it does, and nothing in it knows which store, executor or surface it will run under.