[BUG] FleetView: marketplace plugin agents (plugin:agent) fail to load

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

Plugin-qualified agent names (e.g. my-plugin:my-agent) are not resolved correctly in two places:

1. claude agents --agent flag (CLI)

• --agent "my-agent" or --agent "my-plugin" → emits warning _"no agent named 'my-plugin' — spawning with default template"_ but does load a session
• --agent "my-plugin:my-agent" → no warning, but the agent does not load at all (silent failure)

2. FleetView (claude agents TUI)

• Typing @my-agent, @my-plugin, or @my-plugin:my-agent in the new-session prompt → none appear in the autocomplete list
• Pressing Enter with any of these does not start a session with the intended agent

What Should Happen?

• --agent "plugin:agent" should resolve the agent from the named plugin and start the session with it (no warning, no silent failure)
• FleetView autocomplete should list agents from installed marketplace plugins and load them correctly when selected

Steps to Reproduce

CLI path:

1. Install a plugin from the marketplace (e.g. my-plugin) that defines an agent (e.g. my-agent)
2. Run claude agents --agent "my-plugin:my-agent"
3. Expected: session starts with agent my-agent from plugin my-plugin
4. Actual: no warning, no agent loaded

FleetView path:

1. Open FleetView: claude agents
2. Start a new background session
3. Type @my-plugin:my-agent (or @my-agent, @my-plugin) in the agent selector
4. Expected: agent appears in autocomplete and loads on Enter
5. Actual: nothing appears; Enter does not load the agent

Error Messages/Logs

# --agent "my-plugin" (short name):
no agent named 'my-plugin' — spawning with default template

# --agent "my-plugin:my-agent" (qualified name):
(no output — silent failure)

# FleetView:
(no output — silent failure)

Claude Model

Not sure / Multiple models

Is this a regression?

I don't know

Last Working Version

N/A

Claude Code Version

2.1.186 (Claude Code)

Platform

Anthropic API

Operating System

Ubuntu/Debian Linux (Ubuntu 25.04)

Terminal/Shell

Other (kitty and Konsole — reproduced in both)