Claude Code Source Code Exposed: Inside Anthropic's Massive Slip-Up

Anthropic has reportedly confirmed to Axios that it accidentally exposed the source code of Claude Code during a routine update. According to the report, a debugging file was mistakenly included in a software package and published to a public developer registry, allowing access to the code. The incident is particularly notable because it is the second such leak in a year, with a similar issue having occurred earlier in February, raising fresh concerns about security and operational practices.

Source code is the original set of instructions developers write to tell software how to work. Written in programming languages such as Python or JavaScript, it acts as the blueprint that controls everything from how a button responds to how data is processed in the background. What users see on their screens is only the final output, while the source code is the logic that actually makes the app function. A simple way to understand it is to think of it as a recipe, the finished dish is what users experience, but the recipe explains exactly how it was created step by step.

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The issue involving Claude Code came to light after a security researcher discovered that a software package contained a source map file capable of revealing the full underlying codebase. Reports said the code was quickly copied and analysed across GitHub, after which Anthropic reportedly began issuing DMCA takedown notices to remove mirrors of the leaked files. Soon after, a South Korean developer named Sigrid Jin rebuilt the core architecture in Python using an AI orchestration tool and released a new project called "claw-code," which is described as a reimplementation rather than a direct copy of the original code.

Reports also suggested that the leaked code included several feature flags pointing to tools that may already be developed but not yet publicly released. These reportedly include the ability for Claude to review its recent sessions to identify improvements, a "persistent assistant" mode that could allow the tool to continue running in the background, and remote access features that let users control the assistant from another device. In simple terms, the leak may have allowed developers not only to understand how the current version works but also to see what new features were being prepared.

According to an Anthropic spokesperson, the incident happened because a Claude Code release accidentally included internal source code, but no customer data or credentials were exposed. The company said the issue was caused by a packaging error rather than a security breach and that steps are now being taken to prevent it from happening again. Reports also note that a similar incident had already occurred in February 2025, when an early version of Claude Code was briefly exposed before being removed.

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