Rival.tips

Fingerprints the writing style of 178 AI models and maps the clusters

Rival.tips is a research tool and interactive visualization that fingerprints the stylistic DNA of 178 AI language models — measuring vocabulary patterns, sentence structure preferences, hedging language frequency, formality registers, and punctuation habits — then clusters them into a navigable map showing which models write like which. The result is a kind of "accent atlas" for AI: you can see at a glance that GPT-4o and Claude Sonnet cluster together on formality but diverge sharply on hedging language, while Llama-3 and Mistral write more similarly to each other than either does to any OpenAI or Anthropic model. The tool works by running a standardized suite of 40 prompts across all 178 models, extracting 120 stylometric features per response, and reducing the high-dimensional space to an interactive 2D UMAP projection. The Show HN post hit 68 points with discussion focusing on the methodological choices and surprising cluster assignments — several models that market themselves as distinct turned out to be nearly indistinguishable stylistically. Practical applications include AI content detection research, model selection for brand voice matching, and detecting when a provider has silently updated their model (stylometric drift is often detectable before the provider announces it). The methodology and raw data are fully open.

Panel Reviews

The Builder

Developer Perspective

Ship

“The stylometric drift detection use case alone makes this worth bookmarking — being able to empirically verify when a model has been updated rather than relying on changelogs is genuinely useful for production systems that depend on consistent output behavior.”

The Skeptic

Reality Check

Skip

“Stylometric analysis based on 40 prompts is a fragile basis for strong claims about model identity. Writing style varies wildly with prompt framing, temperature, and system prompt — the clusters here may be measuring prompt sensitivity as much as genuine model character.”

The Futurist

Big Picture

Ship

“As AI-generated text becomes the default for much of the written web, tools that can map and distinguish model identities are going to be foundational for authenticity, attribution, and detecting when models are being impersonated or copied.”

The Creator

Content & Design

Ship

“For brand voice work this is immediately useful — I can finally have a data-driven answer to 'which model sounds most like our brand' rather than vibes-based prompt testing. The visual cluster map is intuitive and genuinely fun to explore.”