Extensions page: re-auth on an MCP server freezes the whole TUI, and the Diagnose button does nothing

[Hmbown]

Founder live-report, 2026-09-07, current main.

Repro

1. Open the plugins / extensions page.
2. Find an MCP server whose auth has gone stale (the ones showing a re-auth action).
3. Activate re-auth.
4. The entire UI freezes. While frozen, activating Diagnose does nothing.

Expected

• Re-auth should run in the background like the rest of the MCP login paths — the machinery already exists (mcp_login_cell + mcp_login_cancel Esc handling), so the UI must stay responsive and show progress/receipt.
• Diagnose should run /mcp validate for that server and surface a receipt, or at minimum stay clickable and report why it can't run.

Suspect area (anchors)

• Recovery-kind mapping in the extensions view: crates/tui/src/tui/views/extensions.rs (~1144–1206; re-auth maps to /mcp login <server> per mcp_item_action_for_stale_oauth_is_login at ~1799).
• McpRecoveryKind incl. Diagnose → /mcp validate: crates/tui/src/mcp.rs:4452–4538.
• Background login cell + cancel token: crates/tui/src/tui/app.rs:2268–2273, delivery in crates/tui/src/tui/ui/event_loop.rs:1527–1538, Esc path in crates/tui/src/tui/ui/handlers.rs:568.

The freeze smells like work running synchronously on the UI thread (or input starved while a refresh holds a lock) in exactly the area #5971 touched this cycle (need-login-first + refresh receipts) — that merge is a reasonable bisect point.

Environment

• macOS, TUI, current main (post d5beab0).