Project membership of Code sessions is machine-local and silently un-syncable - Projects sync across devices, their contents do not

Environment

• Claude Desktop app on Windows 11 (Claude Code 2.1.217), two machines (laptop + PC), same account
• Claude Pro/Max account with a claude.ai Project ("Range Detector Strategy")

What happens

On my laptop, my Claude Code sessions are organized under my Project in the Code sidebar. On my PC, logged into the same account:

• The Project header itself appears (so Projects clearly sync account-side)
• But the Project is empty — "Drag or move sessions here" — and every session sits in "Ungrouped"

So the container syncs, but which sessions live inside it does not. Nothing in the UI warns you about this. I spent an entire evening assuming my data or my setup was broken before discovering the assignments are stored in per-machine local app state (IndexedDB), which #53340 already documents.

Why this is worse than a papercut

1. The feature looks account-level but behaves machine-level. A Project that follows me to every device, whose contents don't, is actively misleading.
2. There is no workaround besides re-dragging by hand on every machine. No CLI flag, no config key, no MCP tool, no export/import. I verified transcripts (~/.claude/projects/**/*.jsonl) carry no project association at all.
3. Even single-machine state is fragile. #53340 and #79156 document updates flattening sidebar organization. So the manual re-drag work isn't even durable.
4. This is undocumented. Neither the desktop docs, the sessions docs, nor the Projects help-center articles mention how Code sessions relate to Projects — I checked all of them.

Expected behavior

Project membership of Code sessions should be stored account-side and sync to every logged-in device, exactly like the Project itself does. Failing that, at minimum:

• a documented, scriptable way to assign sessions to a Project (CLI or config), and/or
• export/import of sidebar organization so multi-machine users can carry it over

Steps to reproduce

1. On machine A, move Code sessions into a Project in the desktop app sidebar
2. Log into the same account on machine B
3. Machine B shows the Project header but zero sessions inside it; all sessions are "Ungrouped"

Related

• #53340 (project folders in sidebar lost; grouping data in IndexedDB)
• #79156 (auto-update flattened all Code sidebar groups)
• #72126 (manual sidebar group management)
• #2511 (connect Claude Code to Claude Projects)

Multi-device use is a first-class workflow for Claude Code — Remote Control exists precisely because people move between machines. Sidebar organization needs to move with them.