[BUG] Cursor extension: Web-tier sessions list but fail to open with "No conversation found with session ID"

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

In the Claude Code extension for Cursor, sessions listed under the Web tab return an error when clicked. Local-tier sessions open correctly. Web sessions are visible in the list (so the API call to fetch the list succeeds) but the backend then appears to look them up locally, which fails.

Steps to reproduce

1. Open the Claude Code extension session list in Cursor.
2. Switch to the Web tab.
3. Click any session entry.
4. Observed: error pop-up:

``
Error: Claude Code returned an error result: No conversation found with session ID: <uuid>
``

1. Switch to the Local tab and click any session → opens correctly.

Expected behavior

Selecting a Web-tier session should load the conversation from Anthropic's cloud storage and resume it in the extension panel.

Environment

• macOS Darwin 24.6.0
• Claude Code: 2.1.150 (claude --version)
• Cursor: latest stable (as of 2026-05-23)
• Same Anthropic account used in Claude Desktop where these Web sessions were created.

Notes

• Reproducible on every Web-tier session I tested (n ≥ 5).
• The session UUIDs in the error messages match real sessions visible from Claude Desktop, so the listing pipeline is working; only the open / hydrate step fails.
• Likely cause (educated guess): the extension passes the session ID to the local Claude Code backend, which only knows how to look up sessions in ~/.claude/projects/... and has no path for cloud retrieval.

Suggested priority

Medium — Web sessions are visible but unusable in the Cursor extension, forcing users to switch to Claude Desktop to access them. UX is confusing because nothing in the UI indicates that Web sessions aren't supported here.

What Should Happen?

The existing conversation should open.

Error Messages/Logs

Error: Claude Code returned an error result: No conversation found with session ID: <uuid>

Steps to Reproduce

1. Open the Claude Code extension session list in Cursor.
2. Switch to the Web tab.
3. Click any session entry.
4. Observed: error pop-up appears (see Error Messages/Logs above).
5. Switch to the Local tab and click any session → opens correctly.

Expected behavior

Selecting a Web-tier session should load the conversation from Anthropic's cloud storage and resume it in the extension panel.

Notes

• Reproducible on every Web-tier session tested (n ≥ 5).
• The session UUIDs in the error messages match real sessions visible in Claude Desktop, so the listing pipeline works; only the open/hydrate step fails.
• Likely cause (educated guess): the extension passes the session ID to the local Claude Code backend, which only knows how to look up sessions in ~/.claude/projects/... and has no path for cloud retrieval.

Claude Model

Opus

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

2.1.150

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

_No response_