Per-tab Claude Code session resume in agterm (zsh): each tab resumes its own conversation after a terminal restart

A developer created a zsh function for agterm that enables per-tab Claude Code session persistence across terminal restarts. The solution uses the tab's unique AGTERM_SESSION_ID as the conversation identifier, allowing each tab to resume its own conversation automatically after a restart. The function is dependency-free and idempotent, but is specific to agterm and zsh.

Keep several Claude Code sessions open at once? With this, after the terminal restarts each tab resumes its own conversation instead of a shared "most recent" one. - Solves a concrete pain: multiple parallel Claude Code sessions survive a restart, each reopening exactly its own conversation. - Zero state: the conversation id is the tab's uuid AGTERM SESSION ID . No mapping file to keep in sync or let go stale. - Idempotent: the first launch pins the conversation to the tab --session-id ; later launches continue it --resume - it flips automatically. - Stays out of the way: claude mcp , -p , an explicit claude --resume <other-id , and any launch outside agterm pass through untouched. - Small, dependency-free, pure zsh; options are function-local emulate -L , so nothing leaks into your interactive shell. agterm-specific. It needs a stable per-tab identifier and relies on agterm feeding the restored command back through the login shell that is how the function intercepts it . It won't work as-is in another terminal - you'd adapt it to that terminal's equivalent. Rests on restore behavior that is verified empirically, not documented - it could change between agterm versions. One conversation per tab. Since conversation id = tab id, two live claude processes in the same tab a split/scratch pane shares one AGTERM SESSION ID collide with "Session ID ... is already in use". It shadows the with a shell function. Passthrough is handled, but the list of subcommands/flags that must not be touched has to be kept current if the CLI grows new ones. claude command It knows Claude Code's on-disk layout ~/.claude/projects/ /<id .jsonl . If that storage location changes, the "does this conversation exist" check breaks it would always create, then hit "already in use" on restart . A one-line fix, but worth knowing. zsh only ${:l} , the N glob qualifier, emulate . Bash needs a rewrite. Existing conversations aren't bound to tabs. After you install this, the first launch in a tab starts a new conversation pinned to that tab - it does not adopt an arbitrary earlier one. agterm can remember the command running in a tab and re-run it on restart. The catch: it re-runs the command verbatim, and claude with no arguments is a new conversation, not a continuation. The trick rests on two facts. Every agterm tab has a stable identifier AGTERM SESSION ID that survives a restart. And Claude Code lets you supply a session id from the outside --session-id . So you can use the tab's id as the conversation id - and the tab permanently "owns" one conversation. The function then wraps claude : on the first launch in a tab it pins the conversation to the tab id --session-id ; if that conversation's file already exists on disk it continues it --resume . The whole decision is one check: is <tab-id .jsonl present under ~/.claude/projects/ ? On restart agterm replays the remembered command, the function recognizes "its own" id, sees the conversation already exists, and reopens exactly that one. Each tab, its own. Claude Code: per-agterm-tab session resume. Binds each tab's Claude Code session id to the tab's own uuid AGTERM SESSION ID , so restoring the terminal resumes that tab's own conversation instead of starting fresh. Requires: agterm exports AGTERM SESSION ID, restores running commands + zsh. claude { emulate -L zsh local sid=${AGTERM SESSION ID:l} -z $sid && { command claude "$@"; return; } not in an agterm tab - passthrough if "$1" == --session-id|-r|--resume && "${2:l}" == $sid ; then shift 2 restore replayed our own flag - re-decide below else local a for a in "$@"; do user steering a session/subcommand/headless? case $a in -r|--resume|--session-id|--resume= |--session-id= |-r= |-c|--continue|-p|--print|-v|--version|-h|--help|mcp|update|doctor|config|install|migrate-installer|setup-token command claude "$@"; return ;; - hand off untouched esac done fi local -a f= ~/.claude/projects/ /$sid.jsonl N does this tab's session already exist? if $ f ; then command claude --resume "$sid" "$@" yes - continue it else command claude --session-id "$sid" "$@"; fi no - create it with this fixed id } File: ~/.zshrc - the config your interactive login zsh reads. That matters: agterm feeds the restored command into that shell, so the function must be defined there not in .zshenv / .zprofile . Requirements: zsh; agterm with "Restore running commands on restart" enabled Settings ; Claude Code sessions stored in the default ~/.claude/projects/ . Activate: new tabs/shells pick it up automatically; in an already-open shell run source ~/.zshrc . Verify: open a tab, run claude , say a few words, restart the terminal - the tab should return to the same conversation. ps will show claude --resume <tab-id . Remove: delete the function block from ~/.zshrc .