Agent Branching (Beta)

Beta / preview API. Needs a session store. See agents.md.

A snapshot_id is an immutable checkpoint. Load it with load_chat(snapshot_id=...) and send again — each turn creates a new leaf; the original stays put.

from genkit.agent import InMemorySessionStore

# After a fork, session_id is ambiguous — raise instead of guessing.
store = InMemorySessionStore(reject_ambiguous_session=True)

agent = ai.define_agent(
    name='designer',
    model='googleai/gemini-flash-latest',
    system='You help design a product landing page. Reply briefly.',
    store=store,
)

root = agent.chat()
await root.send('Plan a landing page for a note-taking app.')
checkpoint = root.snapshot_id

minimal = await agent.load_chat(snapshot_id=checkpoint)
await minimal.send('Direction: minimal.')

bold = await agent.load_chat(snapshot_id=checkpoint)
await bold.send('Direction: bold.')

resumed = await agent.load_chat(snapshot_id=bold.snapshot_id)
await resumed.send('Add a pricing section.')

Same pattern for time travel: reopen an earlier snapshot and send a different follow-up. After forks, resume by snapshot_id, not session_id:

# Ambiguous when reject_ambiguous_session=True — pick a leaf instead:
resumed = await agent.load_chat(snapshot_id=bold.snapshot_id)