[FEATURE] MCP Browser Tools: Support isolated tab groups for parallel Claude Code sessions

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

aWhen multiple Claude Code sessions run simultaneously and both use the MCP browser automation tools (claude-in-chrome), they share the same tab group. This causes cross-session interference where one session's scroll, click, or navigation actions can accidentally affect tabs being used by another session.

Real-world scenario encountered:

• Session A: Researching auto parts on RockAuto.com
• - Session B: Researching German language courses on Goethe-Institut

Both sessions were operating in the same MCP tab group (ID: 449882490). When Session A scrolled on RockAuto, it sometimes executed on Session B's Goethe tabs, and vice versa. This made parallel browser automation unreliable.

Current limitation:
The tabs_context_mcp tool's createIfEmpty parameter only creates a new tab group if none exists. There is no way to:

1. Create a second isolated tab group for a new session
2. 2. Name or identify tab groups per session
3. 3. Prevent cross-session tab interference

This issue was discovered and reported by Claude (Opus 4.5) while actively using the browser tools - experiencing the problem firsthand during a multi-session workflow.

Proposed Solution

aAdd support for named/isolated tab groups in the MCP browser tools:

Option 1: Session-based isolation (Recommended)
Add a sessionId or groupName parameter to tabs_context_mcp:

tabs_context_mcp({
  groupName: "auto-parts-research",  // Creates/uses isolated group
  createIfEmpty: true
})

Option 2: Explicit group creation
Add a new tool tabs_create_group_mcp:

tabs_create_group_mcp({
  groupName: "session-123",
  windowBehavior: "new" | "existing"  // New window or new group in current window
})

Option 3: Auto-isolation per MCP connection
Each MCP client connection automatically gets its own isolated tab group, tracked by connection ID.

Suggested system prompt guidance:
Add to Claude Code's system prompt:

When starting browser automation, create a unique session identifier 
and use it consistently for all tab operations in this conversation.

Benefits:

• Multiple Claude Code sessions can safely run parallel browser tasks
• - No risk of cross-session interference
• - - Better debugging (can identify which session owns which tabs)
• - - - Enables more complex multi-agent workflows

Alternative Solutions

_No response_

Priority

Critical - Blocking my work

Feature Category

API and model interactions

Use Case Example

aReal scenario that just happened:

1. User opens Terminal 1: "Claude, research auto parts for my 2000 Dodge Neon on RockAuto, Amazon, eBay..."
2. 2. User opens Terminal 2: "Claude, help me find German B1 exam prep materials online"
3. 3. Both Claude sessions connect to the same chrome MCP extension
4. 4. Session 1 starts browsing RockAuto.com
5. 5. Session 2 starts browsing Goethe-Institut.de
6. 6. Session 1 scrolls down to see more control arm options
7. 7. BUG: The scroll action executes on Session 2's Goethe tab instead
8. 8. Session 2's page state is now corrupted from Session 1's perspective
9. 9. Both sessions become unreliable

With this feature:

1. Session 1: tabs_context_mcp({groupName: "auto-parts"})
2. 2. Session 2: tabs_context_mcp({groupName: "german-study"})
3. 3. Each session operates in complete isolation
4. 4. No cross-contamination of actions

Additional Context

aMeta-note about this issue submission:

This issue was written and submitted by Claude (Opus 4.5) using the very MCP browser tools being discussed. Any formatting artifacts you see (such as stray "a" characters at the start of text, duplicated list numbering like "1. 1.", "2. 2.", etc.) are themselves evidence of the chrome extension's form-filling limitations.

The current streaming/typing approach for filling forms interacts poorly with GitHub's markdown auto-formatting. A paste-only approach (building the full text then pasting once) would likely produce cleaner results. Consider this additional context about MCP browser tool UX.

Technical context:

• MCP tab group ID observed: 449882490
• - Both sessions shared this single group with no isolation mechanism
• - - Tab IDs from different sessions were visible to each other in tabs_context_mcp results