termdeck
Resume takes the session id
Continuing a conversation means starting Claude Code again with the id of the session you want. The id is the filename of the transcript, minus the .jsonl extension.
Claude Code guide: resuming a session
How to resume a Claude Code session
A Claude Code session lives on disk as soon as it starts, so resuming is not a recovery feature. It is the normal way to continue a conversation in a new process, whether you closed the terminal on purpose or something closed it for you.
Anthropic
On Claude Code
It happens once, at start
The resume is done when the process starts, not per turn. Everything after that is one continuous run, which is why resuming is cheap even on a long conversation.
Changes made elsewhere need a restart
Because resume happens once, a turn that a terminal appended to the transcript after your process started is not picked up until the next start. Codex re-reads before every turn, Claude does not.
The session id is stable
Continuing a session keeps its id, so the transcript keeps growing in the same file rather than forking into a new one.
Finding the id
List the project directory under ~/.claude/projects and sort by modified time. The most recently touched .jsonl file is the session you were last in.
Compare
How each engine picks a conversation back up
| Claude Code | Codex CLI | Grok CLI | |
|---|---|---|---|
| Resume mechanism | A flag on the next run | An explicit resume call | Session state re-read per turn |
| Happens | Once, at process start | Before every turn | Before every turn |
| Picks up terminal edits | At the next process start | Yes, every turn | Yes, every turn |
| Identified by | Session id | Thread id plus working directory | Session id |
| Cost of resuming | Cheap | Can be slow on a long thread | Cheap |
Termdeck drives all three from one console, so the differences above stop being three separate habits to remember.
FAQ
Claude Code resuming a session, answered
Where do I find my Claude Code session id?
It is the name of the transcript file. Look under the project directory in ~/.claude/projects and take the filename without the .jsonl extension. The most recently modified file is the session you were last working in.
Does resuming a session cost tokens?
Resuming re-establishes the conversation, so the prior context is in play again. That is what makes the continuation coherent, and it is why a very long session gets more expensive per turn than a fresh one on the same task.
Can I resume a session on a different machine?
Only if the transcript file is there. The session lives entirely in the JSONL file on the machine that ran it, so copy the file across first, into the matching project directory.
Why does my resumed session not show a turn I ran in the terminal?
Claude Code reads the transcript when the process starts, not before every turn. A turn appended by another process after yours started is not visible until you start again.
Claude Code, Codex and Grok in one browser console