Is the chat agent/model chosen in Copilot Chat important?

[emma284]

Hi community, I have a doubt about the way code is generated with Spec Kit.

When I initialized the project, I did it with
specify init --here --ai copilot

Then, I ran the commands (/constitution, /specify, /plan, etc.) in Copilot Chat choosing Claude Sonnet 4.5 as AI Agent and Spec Kit started to work.
But, what would happen if I choose Grok Code Fast? The output (code) could be different, or the selected model is not important on how Spec Kit works?

I only found this reference to agents in .md files

3. **Agent context update**:
   - Run `.specify/scripts/bash/update-agent-context.sh copilot`
   - These scripts detect which AI agent is in use

so i'm assuming only matter agent selected on initialize.

Thanks in advance.