Invalid agent configuration generated via /agents command on Windows

Bug Description

The /agents command UI generates an invalid agent configuration, showing the error: "Invalid agent configuration generated". The agent is never created.

Steps to Reproduce

1. Run Claude Code (v2.1.69) on Windows
2. Type /agents
3. Attempt to create a new agent through the dialog
4. Dialog fails with: "Invalid agent configuration generated"

Expected Behavior

The /agents command should successfully create a valid agent .md file in ~/.claude/agents/ with proper YAML frontmatter.

Actual Behavior

The agent creation fails with "Invalid agent configuration generated". No file is written to ~/.claude/agents/.

Workaround

Manually creating an agent .md file in ~/.claude/agents/ with YAML frontmatter works fine:

---
name: my-agent
description: "Agent description here"
---

# Agent instructions here

Environment

• Claude Code version: 2.1.69
• OS: Windows (Git Bash / MINGW64)
• Installation type: Native installer

Debug Log Notes

• Plugin loading shows: Loaded plugins - Enabled: 0, Disabled: 0, Commands: 0, Agents: 0, Errors: 0
• No specific validation error is logged — only the UI message is shown
• ~/.claude/agents/ directory did not exist by default and had to be created manually