[BUG] New Cowork sessions inherit working folder from prior in-memory session (affects both UI "+ New" and claude://cowork/new deeplinks)

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

Summary
When Claude Desktop is already running with an active Cowork session, creating a new Cowork session — whether via the in-app "+ New" button or a claude://cowork/new deeplink — results in the new session inheriting the working folder from the prior session. For deeplinks that pass a folder param, the new session ends up with both the inherited folder and the deeplink's folder attached, rather than only the deeplink's folder. The behavior does not occur on a fresh app launch

Why this is a bug

Documented contract for /new (and the user mental model for "+ New") is a fresh session.
The deeplink's folder parameter is documented in the singular ("adopted as the working directory"), implying authoritative replacement, not additive merge.
UX impact: Confusing for users clicking "+ New" who don't expect prior folders to carry over. Particularly problematic for "Open in Claude Cowork" buttons in third-party tools, where the caller has no visibility into prior session state and cannot reason about what will be attached.
Safety impact: A folder the user intended to scope out of a session remains in scope, expanding the blast radius of any prompt run there. Especially relevant given Cowork's agentic nature and file-write capabilities.

Reference
https://support.claude.com/en/articles/14729294-open-claude-desktop-with-a-link

What Should Happen?

When Claude Desktop is already running with an active Cowork session, creating a new Cowork session —

1. via the in-app "+ New" button : Should create a new session without a working folder set
2. claude://cowork/new deeplink: Should result in a new session with working folder only set to parameters passed in the deep link

Error Messages/Logs

Steps to Reproduce

Steps to reproduce — deeplink path

1. Launch Claude Desktop.
2. Fire claude://cowork/new?q=Draft the Q2 update&folder=/Users/me/docs → session opens with /Users/me/docs. ✅
3. Without quitting the app, fire claude://cowork/new?q=Draft the Q2 update&folder=/Users/me/downloads.
4. Actual: new session has both /Users/me/downloads and /Users/me/docs attached.
5. Expected: new session has only /Users/me/downloads attached.

Steps to reproduce — UI path

1. Launch Claude Desktop.
2. Open a Cowork session with /Users/me/docs as the working folder.
3. Click "+ New" to create a new Cowork session. Do not manually add any folder.
4. Actual: new session has /Users/me/docs pre-attached.
5. Expected: new session has an empty working directory.

Isolating tests run

Test A — fresh app launch: Fully quit, relaunch, fire deeplink as the first action → only the deeplink's folder is attached. ✅ Rules out persisted state and confirms the carryover lives in in-memory session state.
Test B — UI "+ New": Creating a new session via the UI button reproduces the carryover → bug is at the session-creation layer, not deeplink-specific.

Claude Model

None

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

Claude 1.4758.0 (fb266c) 2026-04-24T20:22:30.000Z

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

_No response_