Branch and append to a session

You run multi-turn or speculative agent flows and need causal, conflict-safe history.

Open a session and branch

Sessions are causal containers; branches are append-only event lines you can fork.

curl

curl https://api.zumik.ai/v2/sessions/ses_…/branches \
  -H "Authorization: Bearer zk_live_..." \
  -d '{"fork_from_branch_id":"br_main","label":"debug-path"}'

Append with expected_version

Every append carries the version it expects. A changed head returns 409 branch_version_conflict instead of corrupting history.

Python

z.sessions.branches.append(
    "ses_…", "br_…",
    expected_version=17,
    event={"type":"tool_result","content":"build green"},
)

Where to go from here.

Session branching guide (docs)

Purge semantics

Got it running? Measure it.

Once requests flow through Zumik, a diagnostic shows exactly what you are reusing.

Run a diagnostic More quickstarts