[BUG] /simplify skill does not specify subagent_type, first agent launch always fails

What's Wrong?

The built-in /simplify skill instructs Claude to "Launch Three Review Agents in Parallel" (for code reuse, quality, and efficiency), but does not specify any subagent_type in its prompt.

This causes a guaranteed first failure: Claude consistently picks code-simplifier (without namespace prefix) instead of the correct fully-qualified name code-simplifier:code-simplifier, resulting in 3 "Agent type not found" errors on the first attempt.

After the initial failure, Claude retries with a different agent type — but which one it picks is unpredictable and depends on which plugins happen to be installed:

• With feature-dev plugin installed → may use feature-dev:code-reviewer (sonnet model, different behavior than intended)
• Without extra plugins → may fall back to general-purpose
• Either way, the result differs from the intended code-simplifier:code-simplifier (opus model, simplification-focused)

What Should Happen?

The /simplify skill should explicitly specify the correct subagent_type so agents launch successfully on the first attempt with consistent behavior.

Error Messages/Logs

Agent type 'code-simplifier' not found. Available agents: general-purpose, statusline-setup, Explore, Plan, claude-code-guide, code-simplifier:code-simplifier, plugin-dev:agent-creator, ...

(Error repeated 3 times — once for each of the 3 parallel agent launches)

Steps to Reproduce

1. Have the code-simplifier plugin installed (from claude-plugins-official)
2. Make some code changes in a repo
3. Run /simplify
4. Observe: Claude launches 3 agents with subagent_type: "code-simplifier" (missing namespace prefix)
5. All 3 agents fail with "Agent type not found"
6. Claude retries — the agent type it picks depends on installed plugins (unpredictable)

Is this a regression?

I don't know

Claude Code Version

2.1.104

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

Windows Terminal

Additional Information

The root cause is that /simplify is a prompt-only skill that tells Claude what to do (launch 3 review agents) but not which agent types to use. Since plugin agent types require fully-qualified names (namespace:name), Claude needs explicit guidance.

Suggested fix: Add agent type specification in the /simplify prompt, e.g.:

Use subagent_type "code-simplifier:code-simplifier" for all three review agents.