Session Resume And Fork

Definition

The controls for continuing prior Claude Code sessions: resuming/continuing an existing session in place, or forking it to branch a new session without modifying the original transcript.

Key points

• --resume/-r <id> resumes a specific session; --continue/-c continues the most recent one.
• --fork-session branches from an existing session into a new one without modifying the original — parallel exploration from a shared checkpoint.
• SDK exposes the same via session-resume options; combine with --fork-session.
• Sits alongside the other CI CD Headless Flags; forking pairs with --resume to branch from a chosen point.
• For state that must persist across truly independent windows, git checkpoints and Auto Memory complement session resume.

Why it matters for the exam

• D3 (20% of scored content) tests that --fork-session branches without mutating the original — the correct answer when a scenario needs to explore an alternative from a saved point while keeping the original intact.

Common gotchas

• --fork-session does not alter the original session — that non-destructiveness is the point (and the tested distinction from a plain --resume).
• --continue/-c grabs the most recent session; --resume/-r needs an explicit id.

See also

• CI CD Headless Flags
• Auto Memory
• Plan Mode And Explore Subagent

Sources

• docs-tools-agents
• netlight-study-guide