[FEATURE]: Add config to change shell for bash tool

[jdanbrown]

Feature hasn't been suggested before.

• I have verified this feature I'm about to request hasn't been suggested before.
  • I see this feature addition from 2025-05-16, but I think it got lost in the 0.x → 1.0 migration?
    • feat: Make shell configurable via config file #23

Describe the enhancement you want to request

I see that I can configure the shell used by the bash tool with the SHELL env var, But it'd be helpful to be able to configure it via the config file as well.

• https://github.com/sst/opencode/blob/125af820/packages/opencode/src/tool/bash.ts#L62

In my case, I want to change the shell to a docker run on a readonly fs so I can safely set "bash": "allow" instead of having to approve a bunch of shell commands all the time, and this wouldn't make any sense as my global $SHELL since it's something I only want opencode to use.

I can of course make shell aliases and stuff, but it seems like opencode.jsonc is the most natural place to keep it (and go looking for it later).

[github-actions]

This issue might be a duplicate of existing issues. Please check:

• [FEATURE]: allow multiple shell setups and allow switching them at runtime via TUI command #4683: [FEATURE]: allow multiple shell setups and allow switching them at runtime via TUI command

Both issues request the ability to configure the shell used by the bash tool via opencode.jsonc. While #4683 proposes a more comprehensive multi-shell solution with Windows-specific support, it addresses the same core need of your feature request.

Feel free to ignore if your use case requires a simpler implementation than what's proposed in #4683.

[rekram1-node]

yeah gonna make this better tmr

[ariane-emory]

@rekram1-node Any headway on this? If not, I'd be happy to try taking a stab at it. Let me know if you have an preferences about what config property is used.

[rekram1-node]

I'm going to do this we are a bit opinionated with the implementation here

[ariane-emory]

Great, in that case I'll leave it be.

[stevoland]

Really keen to see this also for sandboxing.

Would you consider providing your rough requirements to begin a contribution?

[ariane-emory]

@stevoland I do have a PR that automatically includes the actual shell in use in the Bash tool's description, but it sounds like the maintainers may prefer a different, configuration-based approach, I'm not sure: #4917

[stevoland]

@ariane-emory tool description is somewhat related but I referring to this issue: "Add config to change shell for bash tool", ie: resurrecting something like the previous thing to configure the shell #23

It would help us to adopt in enterprise type org with proper sandboxing of the shell via config rather than forcing our devs to run some wrapper thing/fork

[rekram1-node]

wow you dug into the archives for that PR reference haha

im doing something for this today so any feedback/suggestion/requests you have drop em here as you have been