# Sessions: resume, fork or start fresh

*Claude Certified Architect - Foundations Study Guide · Agentic Architecture & Orchestration · Last updated October 22, 2026 · https://www.certifyforce.com/study-guide/claude-certified-architect-foundations/agentic-architecture-and-orchestration/sessions-resume-fork-or-start-fresh*

When to resume a named or saved session, when to fork it into independent branches, and when to start fresh with a structured summary instead, with the CLI and Agent SDK spellings side by side and what a resumed or forked session does and does not restore.

- Certification: Claude Certified Architect - Foundations
- Exam section: Agentic Architecture & Orchestration
- Study guide: https://www.certifyforce.com/study-guide/claude-certified-architect-foundations

**Official exam objective:**

> Manage session state, resumption, and forking

## What the exam expects

- Continue an investigation across work sessions with `claude --resume <name>`, and resume headless or SDK runs by saved session ID.
- Use `fork_session` to branch independent explorations (two refactoring or testing strategies) from one shared analysis baseline.
- Choose between resuming (prior context mostly valid) and starting fresh with an injected structured summary (prior tool results stale, or the session lives on another machine).
- Tell a resumed session exactly which files changed so it re-reads them instead of re-exploring everything.

Key terms: **session** (the saved conversation history: prompts, tool calls, tool results, responses); **resume** (return to a specific session by ID or name); **continue** (return to the most recent session in the directory); **fork** (a new session that starts with a copy of another's history); **stale tool result** (an earlier file read or query that no longer matches reality).

## Key facts

| Fact | Detail | Source |
|---|---|---|
| What a session persists | Conversation history, not the filesystem | [SDK sessions](https://code.claude.com/docs/en/agent-sdk/sessions) |
| Name a session | `claude -n <name>` or `/rename <name>`; resume with `claude --resume <name>` | [Manage sessions](https://code.claude.com/docs/en/sessions) |
| `--continue` | Most recent session in the directory; skips `claude -p` and SDK sessions | [CLI reference](https://code.claude.com/docs/en/cli-reference) |
| `--fork-session` | New session ID when resuming; use with `--resume` or `--continue` | [CLI reference](https://code.claude.com/docs/en/cli-reference) |
| SDK fork | `resume` plus `fork_session=True` / `forkSession: true`; original unchanged | [SDK sessions](https://code.claude.com/docs/en/agent-sdk/sessions) |
| Multi-user apps | Resume with a tracked `session_id` per user, not continue | [SDK sessions](https://code.claude.com/docs/en/agent-sdk/sessions) |
| Flags not restored | `--mcp-config`, `--settings`, `--plugin-dir`, `--fallback-model`, `--add-dir` | [Manage sessions](https://code.claude.com/docs/en/sessions) |
| Interrupted tool call | Not rerun; marked as cut off, Claude told to check whether it took effect | [Manage sessions](https://code.claude.com/docs/en/sessions) |
| Two terminals, same session, no fork | Messages interleave into one transcript | [Manage sessions](https://code.claude.com/docs/en/sessions) |
| Cross-host resume | Session files are local; use a session store, move the file, or pass results into a fresh prompt | [SDK sessions](https://code.claude.com/docs/en/agent-sdk/sessions) |

## Check yourself

- Why is a structured summary in a new session more reliable than resuming after most files have changed?
- When should an SDK app use `resume` with a stored session ID instead of `continue_conversation`?
- Why can't `claude --continue` find last night's `claude -p` audit?

## Sources

- [Work with sessions](https://code.claude.com/docs/en/agent-sdk/sessions)
- [Manage sessions](https://code.claude.com/docs/en/sessions)
- [CLI reference](https://code.claude.com/docs/en/cli-reference)
- [Best practices for Claude Code](https://code.claude.com/docs/en/best-practices)
- [Rewind file changes with checkpointing (Agent SDK)](https://code.claude.com/docs/en/agent-sdk/file-checkpointing)
- [Checkpointing](https://code.claude.com/docs/en/checkpointing)
- [Claude Certified Architect – Foundations Exam Guide v1.0](https://everpath-course-content.s3-accelerate.amazonaws.com/instructor%2F6nizmqk8tpzpfjvt6qmmav7rh%2Fpublic%2F1783542750%2FClaude+Certified+Architect+%E2%80%93+Foundations+Exam+Guide.pdf)

## About the full unit

The "Core concepts", "Exam traps" and "Worked scenario" sections of this unit, its 12 linked practice questions, and unlimited timed mock exams are included with the Claude Certified Architect - Foundations pack (USD $19): https://www.certifyforce.com/practice-exams