Claude Code's source code has been leaked via a map file in their NPM registry

#1

Post by treexs » Tue, Mar 31, 2026, 9:00 AM UTC

https://xcancel.com/Fried_rice/status/2038894956459290963

Related ongoing thread: The Claude Code Source Leak: fake tools, frustration regexes, undercover mode - https://news.ycombinator.com/item?id=47586778

Claude Code's source code has been leaked via a map file in their NPM registry
twitter.com

Re: Claude Code's source code has been leaked via a map file in their NPM registry

#2

Post by mapcars » Tue, Mar 31, 2026, 9:09 AM UTC

Are there any interesting/uniq features present in it that are not in the alternatives? My understanding is that its just a client for the powerful llm

Re: Claude Code's source code has been leaked via a map file in their NPM registry

#3

Post by LeoDaVibeci » Tue, Mar 31, 2026, 9:11 AM UTC

Isn't it open source?

Or is there an open source front-end and a closed backend?

Re: Claude Code's source code has been leaked via a map file in their NPM registry

#4

Post by yellow_lead » Tue, Mar 31, 2026, 9:14 AM UTC

LeoDaVibeci wrote: post #3

Isn't it open source? Or is there an open source front-end and a closed backend?

No

Re: Claude Code's source code has been leaked via a map file in their NPM registry

#5

Post by avaer » Tue, Mar 31, 2026, 9:14 AM UTC

LeoDaVibeci wrote: post #3

Isn't it open source? Or is there an open source front-end and a closed backend?

No, it was never open source. You could always reverse engineer the cli app but you didn't have access to the source.

Re: Claude Code's source code has been leaked via a map file in their NPM registry

#6

Post by agluszak » Tue, Mar 31, 2026, 9:15 AM UTC

LeoDaVibeci wrote: post #3

Isn't it open source? Or is there an open source front-end and a closed backend?

You may have mistaken it with Codex

https://github.com/openai/codex

Re: Claude Code's source code has been leaked via a map file in their NPM registry

#7

Post by treexs » Tue, Mar 31, 2026, 9:17 AM UTC

The big loss for Anthropic here is how it reveals their product roadmap via feature flags. A big one is their unreleased "assistant mode" with code name kairos.

Just point your agent at this codebase and ask it to find things and you'll find a whole treasure trove of info.

Edit: some other interesting unreleased/hidden features

- The Buddy System: Tamagotchi-style companion creature system with ASCII art sprites

- Undercover mode: Strips ALL Anthropic internal info from commits/PRs for employees on open source contributions

Re: Claude Code's source code has been leaked via a map file in their NPM registry

#8

Post by swimmingbrain » Tue, Mar 31, 2026, 9:18 AM UTC

mapcars wrote: post #2

Are there any interesting/uniq features present in it that are not in the alternatives? My understanding is that its just a client for the powerful llm

From the directory listing having a cost-tracker.ts, upstreamproxy, coordinator, buddy and a full vim directory, it doesn't look like just an API client to me.

Re: Claude Code's source code has been leaked via a map file in their NPM registry

#9

Post by q3k » Tue, Mar 31, 2026, 9:19 AM UTC

The code looks, at a glance, as bad as you expect.

Re: Claude Code's source code has been leaked via a map file in their NPM registry

#10

Post by dragonwriter » Tue, Mar 31, 2026, 9:20 AM UTC

LeoDaVibeci wrote: post #3

Isn't it open source? Or is there an open source front-end and a closed backend?

> Isn't it open source?

No, its not even source available,.

> Or is there an open source front-end and a closed backend?

No, its all proprietary. None of it is open source.