[FEATURE] Mods: let a mod open the browser pane (auto mode refuses $.mcp.call to preview_start)

Status Open

Reported on v2.1.286

Maintainer reply None cached

Activity 0 comments · opened Oct 3, 2026

Preflight Checklist

[x] I have searched existing requests and this feature hasn't been requested yet
[x] This is a single feature request (not multiple features)

Problem Statement

A mod can't open the desktop app's browser pane. $.mcp.call('Claude_Browser', 'preview_start', { url }) from a command.run hook (the user typed the mod's slash command) is refused in auto mode:

The server-side auto mode classifier gave no verdict for mcp__Claude_Browser__preview_start: the request that produced this action did not ask for one.

Adding mcp__Claude_Browser__preview_start to permissions.allow in the project's .claude/settings.json doesn't change that, also in a new session.

Proposed Solution

Treat a slash command the user typed as the request behind the mod's calls in that command.run hook, or honour permissions.allow rules for a plugin's $.mcp.call. Alternatively a dedicated $.ui call to open a URL in the browser pane.

Alternative Solutions

Today the mod falls back to $.prompt.submit, asking Claude to open the page. That works, but costs a model turn every time the command runs.

Priority

Low - Nice to have

Feature Category

Developer tools/SDK

Use Case Example

/picture-review starts a local review server ($.process.spawn) and should show its page in the browser pane right away.

Additional Context

Claude Code 2.1.286, desktop app, Windows, auto mode.

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