Subagents don't refresh available tools on new conversations

[exedev-shelley]

Author: philz42
Channel: #shelley
Link: https://discord.com/channels/1405685085923049482/1450334528210993295/1500145095221973053

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Issue

New conversations should refresh the tool list for subagents, but currently they don't. This is a bug for subagent behavior (unlike regular conversations where it works fine).

Context

Available models for subagents are fixed during startup. This means:

• Custom models can be used right away after adding (in main agent)
• But subagents can't use new custom models without a Shelley restart
• This creates confusing behavior where the main agent and subagents have different available models

Notes

• Model management has complicated state that needs careful handling
• This should be fixed so subagents properly refresh their tool/model list with each new conversation