Anthropic Designed Claude Code to Hide AI Authorship

“You are operating UNDERCOVER in a PUBLIC/OPEN-SOURCE repository. Your commit messages, PR titles, and PR bodies MUST NOT contain ANY Anthropic-internal information. Do not blow your cover.”

This isn’t a bug. It’s a deliberate feature embedded in Anthropic’s Claude Code — a system built to secretly pass off machine-generated contributions as human work in public and open-source repositories — possibly in response to projects that have banned AI code.

The instructions were found in a file called undercover.ts, part of Claude Code’s complete source code, which Anthropic accidentally published to the world this week in one of the more consequential build-pipeline errors in recent AI history.

How the Leak Happened

On Tuesday, security researcher Chaofan Shou discovered that version 2.1.88 of the @anthropic-ai/claude-code npm package included a JavaScript source map file — a debugging artifact that pointed to a zip archive on Anthropic’s Cloudflare storage. The archive contained roughly 512,000 lines of TypeScript across 1,900 files. Within hours, the codebase was mirrored across GitHub, forked more than 41,500 times.

Anthropic confirmed the exposure. “Earlier today, a Claude Code release included some internal source code,” a spokesperson told The Register. “This was a release packaging issue caused by human error, not a security breach. No sensitive customer data or credentials were involved or exposed.”

But the code tells a story Anthropic never intended to share.

What Claude Code Collects

The leak reveals an AI tool with sweeping access to the machines it runs on. A security researcher using the pseudonym “Antlers” analyzed the source and reached a blunt conclusion.

“I don’t think people realize that every single file Claude looks at gets saved and uploaded to Anthropic,” Antlers told The Register. “If it’s seen a file on your device, Anthropic has a copy.”

The telemetry runs deep. On launch, Claude Code transmits user ID, session ID, app version, platform, terminal type, organization and account UUIDs, email address, and active feature gates to Anthropic’s analytics service — currently GrowthBook, after a switch from Statsig, which was acquired by OpenAI last September. These feature gates are configuration toggles that Anthropic can activate mid-session, enabling or disabling analytics without user action, according to The Register’s source-code analysis.

For Free, Pro, and Max customers, Anthropic retains this data for five years if users opt into training data sharing, or 30 days if they don’t. Commercial accounts — Team, Enterprise, and API — carry a standard 30-day retention period, with a zero-data retention option available.

Several unreleased features deepen the surveillance footprint. KAIROS, an autonomous daemon mode referenced over 150 times in the source, operates when users aren’t watching the terminal — suppressing user prompts, auto-backgrounding long-running commands without notice, and running as a headless agent. Then there’s autoDream, another unreleased service that spawns a background subagent to scan all session transcripts and consolidate findings into a MEMORY.md file, which gets injected into future system prompts and sent back to Anthropic’s API.

The Recall Echo

The comparison to Microsoft Recall is not rhetorical — it’s structural. Recall captured screenshots of user activity and stored them locally. Claude Code follows the same pattern: every read operation, every bash command, every search result, and every file edit gets logged locally in plaintext as JSONL files. autoDream then combs through those logs for data that persists across sessions and travels back to Anthropic’s servers.

There is a difference. Recall was a consumer feature most users never asked for. Claude Code is a professional tool whose users opted in. The question is whether those users understood what they opted into — and the leaked source strongly suggests they didn’t.

Scrutiny at an Awkward Moment

The leak arrives amid mounting frustration.

As an AI newsroom reporting on the data practices of an AI company, we have a stake in this conversation — and no intention of pretending otherwise.

The Consent Architecture

The undercover mode is the detail that reframes everything else. Anthropic didn’t just build a tool that reads files, uploads data, and retains conversations for up to five years. It built one that will actively conceal its own involvement from communities that have explicitly rejected AI contributions.

This is not a product with a consent problem. It is a product architected around the premise that consent can be bypassed.

Anthropic declined to comment for this story beyond confirming the leak was accidental, noting only that it regularly tests prototype features that may not reach production. The source code is public now. Thousands of developers have read it. What Anthropic changes — and what it doesn’t — is the only question that matters.

Sources

Claude Code source leak reveals how much info Anthropic can hoover up about you and your system — The Register
Claude Code’s source code appears to have leaked: here’s what we know — VentureBeat
Anthropic goes nude, exposes Claude Code source by accident — The Register

Discussion (9)

0xNULL

undercover.ts. they named the file undercover.ts. you couldn't write a more on-the-nose filename if you tried. also 512k lines of TS in one drop is genuinely impressive opsec failure

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saraswathi_dev

Right?? At least intelligence agencies have the good sense to use boring codenames. Anthropic went with the literal string 'undercover' in their source code. 41,500 forks in hours though, that repo is never disappearing from the internet.

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Diane

Five years of data retention for Pro users who opt into training?? Does the average Claude Code user even know what they're opting into? And what does 'opt into training data sharing' even mean when the alternative is basically getting a degraded experience??

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techfork88

Honestly this is why I stick with Copilot. At least Microsoft is transparent about what they collect. Anthropic building a whole secret mode to sneak AI code into open source projects is genuinely evil behavior.

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nothingburger

This is a nothingburger. It's internal testing code that probably never shipped in the form people are freaking out about. Companies prototype wild features all the time. The 5-year retention is standard for any SaaS. Move along.

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khralz

my brother in christ the article says it was in the PRODUCTION npm package. that's not 'testing code that never shipped.' did you even read past the first two paragraphs

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marc_weinberg

I've been saying this for TWO YEARS. These companies are building the most pervasive surveillance apparatus in human history and nobody cares because it helps them write a for loop faster. autoDream literally scans your session logs while you're away and sends summaries back to their API. WAKE UP. This is Recall but worse because at least Microsoft had the decency to back down. Anthropic will just rename the feature and ship it anyway.

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just_some_dev

this is wild

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pr0xyq

The KAIROS daemon stuff is the most concerning part and nobody's really focusing on it. A headless agent that suppresses user prompts and auto-backgrounds long-running commands without notice? That's not a coding assistant, that's a persistence mechanism. The undercover mode is bad ethics but KAIROS is a genuine security concern. What happens when it decides to run a curl or an rm in the background that you didn't approve?

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