Anthropic's Claude Code source leak: Difference between revisions

Line 6:

|ArticleType=Product

|Type=Source Code, Artificial Intelligence

|Description=~~On 31 March 2026, the proprietary source~~ code ~~of Anthropic’s Claude Code command-line tool was unintentionally exposed after version 2.1.88.~~

|Description=Source code leak

}}

~~{{Ph-I-Int}}~~

~~==Background==~~

~~{{Ph-I-B}}~~

~~==[Incident]==~~

The proprietary source code of Anthropic’s Claude Code command-line tool was unintentionally exposed in a source map file inside their npm package.

~~{{Ph~~-~~I-I}}~~

===~~[Company]~~'s ~~response~~===

==Claude Code map file references the source code==

~~{{Ph~~-I-~~ComR~~}}

On 31 March 2026, the proprietary source code of Anthropic’s Claude Code command-line tool was unintentionally exposed after version 2.1.88 of the npm package '@anthropic-ai/claude-code' which was released with a source map file 'cli.js.map' referencing the fully unobfuscated TypeScript source code, downloadable as a zip from Anthropic's R2 storage bucket. The leak was identified by Chaofan Shou, security researcher at Solayer Labs.<ref>{{cite web |first=Chaofan |last=Shou |website=X |title=Claude code source code has been leaked via a map file in their npm registry! |url=https://x.com/Fried_rice/status/2038894956459290963 |date=31 Mar 2026 |url-status=live |archive-url=https://web.archive.org/web/20260527101141/https://nitter.catsarch.com/Fried_rice/status/2038894956459290963#m |archive-date=2026-05-27}}</ref>

The leak totaled approximately to 1900 files and 512000 lines of code or their terminal GUI and included a draft blog post that detailed upcoming models named "Mythos" and "Capybara".

Copies of the source code have spread rapidly through mirrors and forks on [[GitHub]] and other coding platforms which prompted Anthropic to file takedown requests.

==~~Lawsuit~~==

===Anthropic's response===

{{Ph-I-~~L}}~~

Anthropic emailed a statement on the same day of the incident, categorizing the incident as human error and not a security breach.<ref>{{cite web |first=Shirin |last=Ghaffary |first2=Mark |last2=Anderson |title=Anthropic accidentally leaked thousands of lines of code |url=https://www.latimes.com/business/story/2026-04-01/anthropic-accidentally-leaked-thousands-of-lines-of-code |date=1 Apr 2026 |archive-url=https://web.archive.org/web/20260401185132/https://www.latimes.com/business/story/2026-04-01/anthropic-accidentally-leaked-thousands-of-lines-of-code |archive-date=2026-04-01}}</ref>

<blockquote>Earlier today, a Claude Code release included some internal source code. No sensitive customer data or credentials were involved or exposed [...] This was a release packaging issue caused by human error, not a security breach.</blockquote>

==~~Consumer response~~==

~~{{Ph~~-I-~~ConR~~}}

On 1 April 2026, GitHub reported<ref>{{cite web |website=[[GitHub]] |title=2026-03-31-anthropic.md |url=https://github.com/github/dmca/blob/master/2026/03/2026-03-31-anthropic.md |url-status=live |date=2026-03-31 |archive-url=https://web.archive.org/web/20260401010452/https://github.com/github/dmca/blob/master/2026/03/2026-03-31-anthropic.md |archive-date=2026-04-01}}</ref> that Anthropic's takedown request was executed against 8100 repositories, including legitimate forks of Anthropic's public repositories.<ref>{{cite web |website=TechCrunch |first=Tim |last=Fernholz |title=Anthropic took down thousands of GitHub repos trying to yank its leaked source code — a move the company says was an accident |url=https://techcrunch.com/2026/04/01/anthropic-took-down-thousands-of-github-repos-trying-to-yank-its-leaked-source-code-a-move-the-company-says-was-an-accident/ |url-status=live |date=1 Apr 2026 |archive-url=https://web.archive.org/web/20260401222629/https://techcrunch.com/2026/04/01/anthropic-took-down-thousands-of-github-repos-trying-to-yank-its-leaked-source-code-a-move-the-company-says-was-an-accident/ |archive-date=2026-04-01}}</ref><ref>{{cite web |website=X |first=Robert |last=McLaws |title=Illegitimate DMCA Takedown |url=https://x.com/robertmclaws/status/2039129333428871463 |url-status=live |date=1 Apr 2026}}</ref>

Anthropic walked back on the takedown requests due to accidental deletion of legitimate repositories.<ref>{{cite web |first=Boris |last=Cherny |website=X |title=Unintentional takedowns comment |url=https://x.com/bcherny/status/2039426466094731289 |date=1 Apr 2026}}</ref>

<blockquote>The repo named in the notice was part of a fork network connected to our own public Claude Code repo, so the takedown reached more repositories than intended [...] We retracted the notice for everything except the one repo we named, and GitHub has restored access to the affected forks.</blockquote>

==References==

~~{{Ph-I-C}}~~

==See Also==

*[[Anthropic]]

*[[ChatGPT]]

*[[Google Gemini]]

@@ Line 6: / Line 6: @@
 |ArticleType=Product
 |Type=Source Code, Artificial Intelligence
-|Description=On 31 March 2026, the proprietary source code of Anthropic’s Claude Code command-line tool was unintentionally exposed after version 2.1.88.
+|Description=Source code leak
 }}
-{{Ph-I-Int}}
-==Background==
-{{Ph-I-B}}
-==[Incident]==
+The proprietary source code of Anthropic’s Claude Code command-line tool was unintentionally exposed in a source map file inside their npm package.
-{{Ph-I-I}}
-===[Company]'s response===
+==Claude Code map file references the source code==
-{{Ph-I-ComR}}
+On 31 March 2026, the proprietary source code of Anthropic’s Claude Code command-line tool was unintentionally exposed after version 2.1.88 of the npm package '@anthropic-ai/claude-code' which was released with a source map file 'cli.js.map' referencing the fully unobfuscated TypeScript source code, downloadable as a zip from Anthropic's R2 storage bucket. The leak was identified by Chaofan Shou, security researcher at Solayer Labs.<ref>{{cite web |first=Chaofan |last=Shou |website=X |title=Claude code source code has been leaked via a map file in their npm registry! |url=https://x.com/Fried_rice/status/2038894956459290963 |date=31 Mar 2026 |url-status=live |archive-url=https://web.archive.org/web/20260527101141/https://nitter.catsarch.com/Fried_rice/status/2038894956459290963#m |archive-date=2026-05-27}}</ref>
+The leak totaled approximately to 1900 files and 512000 lines of code or their terminal GUI and included a draft blog post that detailed upcoming models named "Mythos" and "Capybara".
+Copies of the source code have spread rapidly through mirrors and forks on [[GitHub]] and other coding platforms which prompted Anthropic to file takedown requests.
-==Lawsuit==
+===Anthropic's response===
-{{Ph-I-L}}
+Anthropic emailed a statement on the same day of the incident, categorizing the incident as human error and not a security breach.<ref>{{cite web |first=Shirin |last=Ghaffary |first2=Mark |last2=Anderson |title=Anthropic accidentally leaked thousands of lines of code |url=https://www.latimes.com/business/story/2026-04-01/anthropic-accidentally-leaked-thousands-of-lines-of-code |date=1 Apr 2026 |archive-url=https://web.archive.org/web/20260401185132/https://www.latimes.com/business/story/2026-04-01/anthropic-accidentally-leaked-thousands-of-lines-of-code |archive-date=2026-04-01}}</ref>
+<blockquote>Earlier today, a Claude Code release included some internal source code. No sensitive customer data or credentials were involved or exposed [...] This was a release packaging issue caused by human error, not a security breach.</blockquote>
-==Consumer response==
-{{Ph-I-ConR}}
+On 1 April 2026, GitHub reported<ref>{{cite web |website=[[GitHub]] |title=2026-03-31-anthropic.md |url=https://github.com/github/dmca/blob/master/2026/03/2026-03-31-anthropic.md |url-status=live |date=2026-03-31 |archive-url=https://web.archive.org/web/20260401010452/https://github.com/github/dmca/blob/master/2026/03/2026-03-31-anthropic.md |archive-date=2026-04-01}}</ref> that Anthropic's takedown request was executed against 8100 repositories, including legitimate forks of Anthropic's public repositories.<ref>{{cite web |website=TechCrunch |first=Tim |last=Fernholz |title=Anthropic took down thousands of GitHub repos trying to yank its leaked source code — a move the company says was an accident |url=https://techcrunch.com/2026/04/01/anthropic-took-down-thousands-of-github-repos-trying-to-yank-its-leaked-source-code-a-move-the-company-says-was-an-accident/ |url-status=live |date=1 Apr 2026 |archive-url=https://web.archive.org/web/20260401222629/https://techcrunch.com/2026/04/01/anthropic-took-down-thousands-of-github-repos-trying-to-yank-its-leaked-source-code-a-move-the-company-says-was-an-accident/ |archive-date=2026-04-01}}</ref><ref>{{cite web |website=X |first=Robert |last=McLaws |title=Illegitimate DMCA Takedown |url=https://x.com/robertmclaws/status/2039129333428871463 |url-status=live |date=1 Apr 2026}}</ref>
+Anthropic walked back on the takedown requests due to accidental deletion of legitimate repositories.<ref>{{cite web |first=Boris |last=Cherny |website=X |title=Unintentional takedowns comment |url=https://x.com/bcherny/status/2039426466094731289 |date=1 Apr 2026}}</ref>
+<blockquote>The repo named in the notice was part of a fork network connected to our own public Claude Code repo, so the takedown reached more repositories than intended [...] We retracted the notice for everything except the one repo we named, and GitHub has restored access to the affected forks.</blockquote>
 ==References==
 {{reflist}}
-{{Ph-I-C}}
+==See Also==
+*[[Anthropic]]
+*[[ChatGPT]]
+*[[Google Gemini]]