MCPViewerScreen

Key bindings for navigation, expansion, and cancel.

All bindings use priority=True so they take precedence over the embedded filter Input. Vim-style j/k bindings are deliberately omitted because they would prevent typing those letters into the always-focused filter input — same rationale as model_selector.py.

Replace the displayed server list; typically after server startup.

Rebuilds the modal body in place so a user who opened /mcp before tools finished loading sees them appear without closing/reopening. Also used by the in-place disable toggle so the cursor lands back on the same server header after F2.

The active filter is cleared on refresh: the connecting placeholder suppresses the filter input, so _query cannot be non-empty when this is called. Resetting it also prevents the programmatic Input(value=...) mount in _mount_body from triggering a redundant Input.Changed repopulation.

This is async because body.remove_children() must complete before _mount_body re-inserts an Input(id="mcp-filter") — Textual defers child removal, so a non-awaited remove leaves the old widget attached and the mount raises DuplicateIds.

Patch a single server's row in place after an F2 toggle.

Surgically updates only the affected server's header and tool rows so unchanged widgets keep their identity — no full body.remove_children() + remount, which would re-create every MCPToolItem and reintroduce the on_mount truncation flicker across the entire list.

Falls back to refresh_server_info when the toggled server cannot be patched in place: server missing from the new info list, no existing header widget (e.g., the active filter currently hides it), or the new state would filter the server out entirely.

Rebuild the visible tool list whenever the filter input changes.

Only the scroll's children are torn down — the title, filter Input, and help footer stay mounted so focus is preserved across keystrokes.

Compose the screen layout.

Build the body once the screen is mounted.

Smart up: scroll one row inside a tall expanded row, else jump.

If the selected row's top edge is already inside the viewport, jump to the previous row (header or tool), wrapping to the final row from the first. For rows taller than the viewport, pin the new selection's bottom to the viewport so the next Up resumes line-stepping through that row; otherwise just ensure the row is visible. Tab / Shift+Tab jump between server headers (see action_jump_up).

Smart down: scroll one row inside a tall expanded row, else jump.

If the selected row's bottom edge is already inside the viewport, jump to the next row (header or tool), wrapping to the first row from the final one. For rows taller than the viewport, pin the new selection's top to the viewport; otherwise just ensure the row is visible. Tab / Shift+Tab jump between server headers (see action_jump_down).

Jump backward to the nearest server header (Shift+Tab), wrapping.

From a tool row this lands on the current server's own header; from a header it moves to the previous server. Wraps to the final header from the top.

Jump to the next server (Tab), wrapping at the end.

Open the read-only error detail modal for server.

Toggle a tool, start server login, or show server error details.

Tool rows expand or collapse. Activating an unauthenticated server starts login, while activating a healthy OAuth-backed remote server starts re-authentication (see _can_start_login). Error headers open a read-only detail modal. awaiting_reconnect, disabled, healthy non-remote, and healthy non-OAuth headers remain no-ops.

Expand or collapse every visible tool at once.

If any visible tool is collapsed, expand all; otherwise collapse all. Operates on tool rows only — server headers are not expandable. Hidden tools (filtered out) keep their state.

Scroll up by one page and snap selection to the topmost visible row.

Without the selection snap, _selected_index would still point at the now-offscreen row, and a subsequent Up/Down press would yank the viewport back to it (see action_move_up / _move_down, which scroll the offscreen selection back into view).

Scroll down by one page and snap selection to the bottommost visible row.

Mirror of action_page_up: prevents a subsequent arrow key from scrolling the viewport back to a now-offscreen selection.

Close the viewer without selecting a server to log into.

Dismiss with the reconnect sentinel when a login is pending.

Bindings are static, so the keybind is always bound; this guard is what makes it a no-op when nothing is queued.

Hand off a toggle-disable request to the app without dismissing.

Only fires when a server header is selected — pressing F2 on a tool row is a no-op. The app's callback persists the new state and is expected to call refresh_server_info(..., select_server=) on this screen, so the user sees the new status without the screen tearing down (which would flicker and reset selection).