[Feature Request] Add setting to disable Preview feature entirely

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

Problem

The "Link to [domain] was blocked. Preview only supports localhost URLs"
toast appears persistently in Claude Desktop, even outside of active
Claude Code sessions (e.g., while chatting in regular conversations on
claude.ai desktop app). It triggers on any non-localhost URL that appears
in the conversation, which is constant during development work where
Claude outputs URLs to docs, GitHub, Stack Overflow, etc.

Closing the Preview panel does not stop the toast. Restarting the app
only helps temporarily.

Current state

There is no way to disable the Preview feature:

• No UI setting
• No flag in settings.json / .claude/settings.local.json
• No documented environment variable
• No CLI argument

Request

Add an explicit setting to fully disable the Preview feature for users
who don't use it, e.g.:

{
  "preview": {
    "enabled": false
  }
}

Alternatively, ensure the Preview URL interception only activates when
a Preview panel is explicitly opened, and fully deactivates when closed.

Environment

• Claude Desktop version: [completá con tu versión — la ves en Settings/About]
• OS: [Windows / macOS / Linux + versión]

Related issues

• #27263 (external URL allowlist)
• #27511 (custom domain allowlist)
• #29354 (multiple tabs/URLs support)

These address adjacent problems but none offer a way to simply turn the
feature off.

Proposed Solution

Option to disable preview

Alternative Solutions

_No response_

Priority

Critical - Blocking my work

Feature Category

CLI commands and flags

Use Case Example

_No response_

Additional Context

Im using claude code (desktop), and can't disable the message about bloking url

<img width="596" height="342" alt="Image" src="https://github.com/user-attachments/assets/16ca488f-86dd-46d1-9c26-4cf276a396eb" />