I kept finding LLM pricing comparison posts that were already stale, so I built a scraper that snapshots the full OpenRouter catalog (425 models, 58 providers) every day and diffs it against the previous day. It's been running unattended for about a week now: https://costpertoken.dev

One thing that fell out of the data surprised me: on the exact same model, a coding-agent-shaped call (large context in, code out) costs roughly 33x more per call than a bulk-classification-shaped call. I checked this on GPT-5.6, Claude Sonnet 5, and Gemini 3.7 Flash and got 33.6x, 33.3x, and 33.3x respectively -- almost identical despite three unrelated pricing tables. Seems to be a property of the call shape, not the vendor. Writeup here: https://costpertoken.dev/guides/why-agent-calls-cost-more-than-chat-calls/

The site is a static Cloudflare Worker. Data collection runs via a local launchd job independent of any AI model or API, specifically so it can't silently stop working.

Feedback and pricing corrections welcome -- it's day 8, so there are rough edges.