Feature: Enable reusing catalog agents as sub-agents in agents.yaml

[ThePlenkov]

Description

Currently, agents discoverable via cagent catalog list cannot be directly reused/referenced in an agents.yaml file's sub_agents configuration.

Current Behavior

• cagent catalog list shows available agents in the catalog
• These catalog agents cannot be directly referenced in sub_agents: [...] in agents.yaml
• There's no way to integrate catalog-discovered agents into a multi-agent setup

Desired Behavior

• Catalog agents should be directly usable as sub-agents in agents.yaml
• Enable seamless integration: discover via catalog → use in config
• Allow something like sub_agents: [pirate] where 'pirate' is a catalog-listed agent

Use Case

As a multi-agent orchestrator, I want to:

1. Discover available agents with cagent catalog list
2. Directly reference those discovered agents in my root agent's sub_agents configuration
3. Build dynamic agent teams from the available catalog without manual path management

Current Limitation

Currently there's no clear way to use catalog-discovered agents in sub_agents configuration, making the catalog less useful for multi-agent orchestration.

Environment

• Using cagent with LiteLLM proxy backend
• Multi-agent orchestration with .cagent/skills.yaml configuration