Shell tool enforces Git and even GitHub usage rules

Description

The prompt in https://github.com/anomalyco/opencode/blob/v1.18.8/packages/opencode/src/tool/shell/shell.txt forces OpenCode to stick to certain conventions when using Git and Github.

While the conventions are not bad per se, I find it undesirable that the shell tool forces everyone to these conventions, that cannot be overridden with Agents.md or even custom agents AFAIK.

I'd like to suggest removing the Git/Github section from here. If it's considered important to keep these instructions, I'd suggest moving them to somewhere where they can be easily overridden at least.

Thanks a lot for OpenCode - it's great!

Plugins

None

OpenCode version

1.18.30

Steps to reproduce

Start opencode and ask "What instructions do you have for git commit".

Or try to tell it to commit current changes without any pre-checks.

Screenshot and/or share link

No response

Operating System

No response

Terminal

No response

Start with packages/opencode/src/tool/shell/shell.txt and locate the Git/GitHub instruction section. Review how this prompt is applied alongside Agents.md and custom agents, then remove or relocate the instructions according to the chosen approach; done when users can override or avoid those conventions as intended.