KillSwitch

KillSwitch is an esoteric programming language created by Dominik Picheta and released under the AGPLv3 license. Its explicit purpose, as stated on the project homepage, is to "break LLMs and coding agents" by being impossible for AI systems to generate or modify correctly. The reference implementation is written in Rust and is freely available on GitHub.

What It Is

KillSwitch is an esolang — a programming language designed for experimental or unconventional purposes rather than practical software development. Unlike most esoteric languages that challenge human programmers, KillSwitch is specifically engineered to defeat large language models and AI coding agents. The language's design makes it structurally resistant to LLM comprehension and generation, serving as both a research artifact and a benchmark tool for evaluating AI coding capabilities.

Design Philosophy: Human-Only Code

The project's README explicitly states that the original code in the repository has been human-written, and the creator intends to continue writing it manually without LLM assistance — not as an ideological stance against AI, but because the author enjoys the process of building software without it. The repository also includes a notice prohibiting AI training on its code, reinforcing the anti-LLM theme throughout the project.

LLM Benchmarks

A companion benchmarks site at bench.killswitch-lang.org tracks how well various LLM models perform on KillSwitch programming tasks. According to the project homepage, Claude Opus 5 currently leads the benchmark rankings. This positions KillSwitch not just as a novelty language but as a practical evaluation harness for measuring AI coding agent capabilities against a deliberately adversarial target.

Architecture and Tooling

The repository includes:

• SPEC.md — the formal language specification
• A reference interpreter installable via cargo install
• A CLI (killswitch run) for executing .ks files
• An anagram utility command for verifying identifier anagrams, hinting at anagram-based syntax as part of the language's LLM-defeating design
• An in-browser playground on the official website for running KillSwitch code interactively

The project is tagged with topics including benchmark, esolang, interpreter, language, and llm on GitHub.

Current Status

The repository was created in July 2026 and last updated in September 2026, indicating active early development. The project has a dedicated website, a live browser-based playground, and a separate benchmarks subdomain, suggesting it has moved beyond a simple proof-of-concept into a more structured open-source project.