Anthropic installed a spyware bridge on my machine?

I've never seen or approved a prompt from Claude if I want any of this to be installed and I've never seen or approved a prompt from macOS that Claude is asking permission to mess around with other apps (though `Application Support` is probably not protected for non-sandboxed apps).

I don't think we should normalise or try to diminish the importance of good security practices. Apps that randomly rewrite how other apps your computer work are generally in the category of malware (and here we're not even considering Claude's apparently ability to execute local instructions based on random text it finds online).

  find ~/Library/Application\ Support -name "com.anthropic.claude_browser_extension\*" -delete

https://github.com/anthropics/claude-code/issues/14616

Of course if they actually did it, without your consent, that's really really bad.

  $ fd claude_browser_extension.json ~/Library
  /Users/miguno/Library/Application Support/BraveSoftware/Brave-Browser/NativeMessagingHosts/com.anthropic.claude_browser_extension.json
  /Users/miguno/Library/Application Support/Vivaldi/NativeMessagingHosts/com.anthropic.claude_browser_extension.json
  /Users/miguno/Library/Application Support/Arc/User Data/NativeMessagingHosts/com.anthropic.claude_browser_extension.json
  /Users/miguno/Library/Application Support/Microsoft Edge/NativeMessagingHosts/com.anthropic.claude_browser_extension.json
  /Users/miguno/Library/Application Support/com.operasoftware.Opera/NativeMessagingHosts/com.anthropic.claude_browser_extension.json
  /Users/miguno/Library/Application Support/Chromium/NativeMessagingHosts/com.anthropic.claude_browser_extension.json
  /Users/miguno/Library/Application Support/Google/Chrome/NativeMessagingHosts/com.anthropic.claude_browser_extension.json

Claude Desktop repeatedly installed/updated these 7 extensions since the beginning of February on my Apple machine. Every entry in the filtered log below is for all 7 extensions:

    $ grep "Installed native host manifest" ~/Library/Logs/Claude/main.log | sed -e 's/ at \/Users\/.*//' | awk '{ print $1" "$2 }' | sort -n | uniq
    2026-02-04 18:53:21
    2026-02-04 23:33:26
    2026-02-04 23:34:20
    2026-02-04 23:34:27
    2026-03-16 09:29:18
    2026-03-17 11:52:22
    2026-03-18 22:22:22
    2026-03-19 14:49:34
    2026-03-20 09:42:03
    2026-03-20 10:10:39
    2026-04-02 22:50:26
    2026-04-02 22:57:56
    2026-04-10 19:38:38
    2026-04-10 19:40:51
    2026-04-12 18:52:36
    2026-04-12 19:10:04
    2026-04-12 20:07:21
    2026-04-15 12:19:46
    2026-04-15 12:20:16
    2026-04-15 12:29:45
    2026-04-16 22:15:47
    2026-04-16 22:24:19
    2026-04-18 10:58:13
    2026-04-18 15:06:54

"Claude Desktop, an Anthropic application, reached across the trust boundary between two independent vendors, and wrote configuration into Brave's application directory. The principle that an application does not silently modify another application is so obvious it rarely gets stated. Anthropic broke it in silence."

This is the key point for me - ask me, let me remove when done. That would be all it takes to not abuse trust.

I mean it almost doesn't matter what is installed at any given time, the agent is going to install stuff you can't realistically observe, the software will auto-update, there is simply no way you can be sure spyware won't end up on your computer.