Feature Request: Allow Custom Mods to Open and Arrange Multiple Sidebar Panels (Panes) Simultaneously

Preflight Checklist

• [x] I have searched existing requests and this feature hasn't been requested yet
• [x] This is a single feature request (not multiple features)

Problem Statement

Currently, the Claude Code Mod API restricts an active mod to a single designated render site or pane slot. If a developer wants to show multiple distinct datasets or separate UI modules simultaneously (e.g., a real-time system log alongside an active file explorer or context status layout), they are forced to funnel everything into a single pane using tabs or custom buttons. This forces the user to switch tabs constantly, preventing real-time, side-by-side data correlation.

Proposed Solution

Extend the interface API for Claude Code Mods to allow a single plugin/mod to declare, open, and manipulate multiple separate panes or sub-panels concurrently. Ideally, this would include layouts such as:

• Split horizontal/vertical panes within the primary sidebar region.
• The ability to dynamically request an additional independent pane region rather than locking into exactly one site.

Alternative Solutions

_No response_

Priority

Medium - Would be very helpful

Feature Category

Other

Use Case Example

_No response_

Additional Context

Benefits

• Deeper Extension Workflows: Enables advanced diagnostic, task tracking, and diff monitoring tools to display complementary information side-by-side.
• Improved UX: Reduces cognitive friction caused by "tab fatigue" inside complex custom mod terminal layouts.