EnterPlanMode tool unnecessarily blocked by 'auto mode unavailable' plan restriction

Bug Description

The EnterPlanMode tool fails with "Auto mode is unavailable for your plan" on paid plans (5x). Plan mode is a read-only exploration phase that restricts editing — it should not require auto mode permissions.

Impact

Plugins/skills that use EnterPlanMode (e.g., superpowers plugin's planning workflows) crash or fail on plans where auto mode is unavailable, even though the plan mode workflow only uses read-only tools (Read, Glob, Grep).

Steps to Reproduce

1. Be on a Claude plan where auto mode is unavailable (e.g., 5x)
2. Have a plugin/skill that calls EnterPlanMode (e.g., superpowers plugin)
3. Trigger a planning workflow
4. Observe: "Auto mode is unavailable for your plan"

Expected Behavior

EnterPlanMode should work independently of auto mode, since it's a read-only restriction — not an auto-approval escalation.

Workaround

Adding to CLAUDE.md: "NEVER use EnterPlanMode or ExitPlanMode" — forces inline planning instead.

Environment

• Claude Code version: latest
• OS: macOS (Darwin 25.3.0)
• Plan: 5x