Plan mode: ExitPlanMode tool not available via ToolSearch

Problem

When entering Plan Mode, the ExitPlanMode tool is referenced in the system prompt instructions but is not available through ToolSearch. The plan mode instructions say:

"At the very end of your turn... you should always call ExitPlanMode to indicate to the user that you are done planning."

But ToolSearch returns "No matching deferred tools found" for both select:ExitPlanMode and keyword search "exit plan". This makes it impossible for the agent to programmatically exit plan mode as instructed.

Environment

• Claude Code on Windows 11
• Model: Opus 4.6 (1M context)
• Date: 2026-04-07

Steps to Reproduce

1. Enter plan mode
2. Complete planning and write plan file
3. Attempt to call ExitPlanMode via ToolSearch
4. Tool not found — plan mode cannot be properly exited by the agent

Expected Behavior

ExitPlanMode should be discoverable via ToolSearch and callable like other deferred tools.

Workaround

User manually exits plan mode via the /plan UI command.