(sidebar): sessions launched by other sessions from throwaway directories become projects #512

Observation

Sessions start other sessions on their own: a running session calls claude -p from Bash, from whatever directory it is in, often its scratchpad under /tmp. Each such directory becomes a new folder under ~/.claude/projects/, and Switchboard lists it as a new project.

Measured on one workstation on 2026-10-09:

• 13 project folders under ~/.claude/projects/ are named after a directory in /tmp;
• 12 hold only sdk-cli transcripts, between 1 and 5 each, and one is empty;
• most were started from the scratchpads of two interactive sessions, -tmp-claude-1000--home-…-workspace-<session-id>-….

Example: an interactive session ran claude -p "List the exact names of every skill available to you in this session…" with its scratchpad as working directory. The project /tmp/claude-1000/-home-…-workspace/<session-id>/scratchpad appeared in the sidebar with that one session.

What already covers part of it

#486 (merged, not released yet) hides sdk-* sessions by default, and the projects that hold nothing else. Every case measured above falls under it.

What it does not cover

• An interactive (cli) session started in a throwaway directory still creates a project that stays listed after the directory is gone.
• Nothing links such a session to the session that started it, so the sidebar cannot nest it under its parent the way Task subagents are nested.
• These launches come from what sessions do on their own (probes, delegated checks), and their frequency is likely to grow. Whether the CLI will mark them (a parent session id, a dedicated entrypoint) is unknown.

To watch

• Once (sidebar): hide sessions launched through the Agent SDK #486 is released: does the sidebar stay clean on a normal day? Count the folders under ~/.claude/projects/ named after /tmp/ directories, and how many of them stay listed.
• New CLI versions: a field naming the parent session, or a launch directory outside ~/.claude/projects/, would let Switchboard nest these sessions or ignore them.
• If listed noise remains, options to weigh:
  • hide projects whose path no longer exists and whose sessions are all older than a threshold;
  • treat directories under the system temp root as ephemeral;
  • let one action archive every such folder at once ((sidebar): archiving a project folder hides the folder until a session appears in it #473).