feat: BROWSER interrupt

[Skn0tt]

What does this PR do?

I'm mainly opening this PR to discuss the approach and spark debate, not with intent to merge it. So take it as a sketch!

Some CLI tools turn interactive, like Git opening a text editor, or Vite opening a browser.

Coding Agent implementations currently struggle with detecting this interactiveness.

• opencode explitictly tells models to use &, making it hard to prevent process leaks
• Claude SDK has an is_background tool param that decides a priori whether a tool call is in the background or not, which means it only works through knowledge of popular tools or mentions in the context

I have a hunch that we should implement the convention of the EDITOR environment variable. When Git needs to open an interactive editor, it spawns the binary in EDITOR and waits until completion. Vite does the same with the BROWSER environment variable.
These env variables are hooks for interactiveness, and Coding Agents can inject themselves to perform the interaction like a user would.

This PR sketches how that could work for BROWSER. If a command calls BROWSER, opencode yields back control to the model and asks it to handle the interaction.

As mentioned, at this point I'd love to hear your thoughts on the approach. Thanks!

How did you verify your code works?

Manual testing, not meant to be merged.

[github-actions]

Thanks for your contribution!

This PR doesn't have a linked issue. All PRs must reference an existing issue.

Please:

1. Open an issue describing the bug/feature (if one doesn't exist)
2. Add Fixes #<number> or Closes #<number> to this PR description

See CONTRIBUTING.md for details.

[github-actions]

The following comment was made by an LLM, it may be inaccurate:

Based on my search results, I found one potentially related PR:

Related PR:

• Process Tools for Interactive CLI commands #2483: Process Tools for Interactive CLI commands
  • This appears to address a similar concern about handling interactive CLI commands, which aligns with the broader problem space that PR feat: BROWSER interrupt #10997 is exploring (detecting and handling interactiveness in CLI tools).

The current PR #10997 is a sketch/discussion PR proposing the BROWSER and EDITOR environment variable convention approach to solve the interactive process detection problem. PR #2483 may be an earlier or related attempt to address interactive CLI command handling.

[github-actions]

Closing this pull request because it has had no updates for more than 60 days. If you plan to continue working on it, feel free to reopen or open a new PR.