Feature Request: Share MCP authentication across git worktrees

Problem

When using git worktrees for parallel development, MCP server authentication doesn't carry over between worktrees. Each worktree prompts for re-authentication even though:

1. MCP OAuth credentials are stored at the user level (~/.claude/.credentials.json)
2. The .mcp.json server definitions are identical (same repo, just different worktree paths)

Root Cause

Credentials in ~/.claude/.credentials.json are keyed by serverName|hash (e.g., linear|638130d5ab3558f4). This hash appears to incorporate the project path, so a worktree at ../wt-1/ generates a different hash than ./wt2-2/ and doesn't find existing credentials.

Use Case

Many teams use git worktrees to run multiple Claude Code sessions in parallel on different features. Having to re-authenticate 5-7 MCP servers in each new worktree creates significant friction.

Proposed Solutions

1. Worktree detection: When Claude Code detects it's running in a git worktree, use the main repository's path for credential hash computation instead of the worktree path.

1. Config option: Add a setting like mcpCredentialRoot that specifies which path to use for credential lookup, allowing users to point all worktrees to a shared credential scope.

1. Content-based hashing: If the hash was based on .mcp.json contents + server URL (rather than file path), worktrees with identical configs would naturally share credentials.

Environment

• macOS (though likely affects all platforms)
• Using HTTP-based MCP servers (Linear, Honeycomb, Figma, Neon, Sentry, etc.)
• Git worktrees created via git worktree add

Workaround

Currently, users must run /mcp and re-authenticate each server in every new worktree, which is tedious but functional.