Session Management
--resume named sessions and fork_session branches.
Why Session Management Matters
The Claude API keeps no server-side state — every request sends the FULL message history. So "a session" is really a saved conversation transcript you can persist, reopen, and branch.
In Claude Code, session tooling lets you resume a named line of work later and fork a shared starting point into parallel explorations. Mastering this is core to D5 (Context Management) and D3 (Claude Code Workflows) on the architect exam.
Resume vs Fork at a Glance
Two primitives solve two different problems:
- --resume <name> — continue a single, named session linearly. Same thread, picked up where you left off.
- fork_session — branch from a shared point into multiple independent lines that don't interfere with each other.
Resume = one timeline continued. Fork = one timeline split into parallel timelines.