1Password credential-request (Claude in Chrome) fails with 'not_connected' despite healthy 1Password app/extension

Summary

The "Claude in Chrome" credential-request integration with 1Password consistently fails with a "not_connected" / "Couldn't connect to 1Password. Check that it's open, then try again." error, even though the 1Password desktop app and browser extension are both confirmed healthy and unlocked.

Environment

• macOS
• 1Password for Mac: was on 8.12.26, updated to 8.12.28 (current stable) during troubleshooting — no change in behavior
• 1Password browser extension: installed, unlocked, and fully functional (confirmed by manually opening the extension popup and browsing vault items while the bug was occurring)
• Claude in Chrome: extension installed and connected (confirmed via the MCP's own list_connected_browsers, which reports the browser as connected)

Steps to reproduce

1. Ask Claude (via Claude Code / Claude in Chrome) to sign into a website using saved 1Password credentials, triggering the credential-request tool.
2. The "Claude needs credentials to continue — Connect 1Password" banner appears.
3. Click "Connect 1Password" and approve in the 1Password app.
4. Banner returns: "Couldn't connect to 1Password. Check that it's open, then try again."

Troubleshooting already performed (all unsuccessful)

• Fully quit and relaunched 1Password (not just closed the window)
• Restarted Claude Code
• Updated 1Password from 8.12.26 to 8.12.28 (latest stable)
• Verified list_connected_browsers shows an active, local browser connection
• Verified the 1Password browser extension itself is unlocked and functional by manually browsing vault items in its popup
• Tested against multiple, unrelated target sites (an internal company dashboard and github.com) — identical failure both times, ruling out a site-specific cause
• The failure occurs at the initial "connect" step, before any site-specific autofill is attempted

Expected behavior

Clicking "Connect 1Password" and approving in the 1Password app should establish the connection so credential requests can proceed.

Actual behavior

Connection consistently fails with "Couldn't connect to 1Password. Check that it's open, then try again," regardless of app restarts, updates, or target site — despite every other layer of the stack (1Password app, 1Password browser extension, Claude-in-Chrome browser connection) being independently verified as healthy.

Notes

• Separately, direct 1Password CLI access (op with a service account token) works perfectly from Claude Code's terminal — so this appears isolated to the Claude-in-Chrome ↔ 1Password extension credential-request bridge specifically, not a general 1Password installation problem.
• Filing here per Claude Code's documented feedback channel; redirect to the appropriate team if this bug belongs elsewhere (Claude in Chrome / claude.ai).