Claude Token Counter, now with model comparisons

The significance here isn't the tool itself but what the tool reveals: Opus 4.7 breaking tokenizer compatibility means developers can no longer assume prompt costs are portable across Claude model versions, adding a new variable to the already fraught calculus of model selection.

Token economics are quietly becoming a front in the Claude-versus-OpenAI coding rivalry. TechCrunch's April 17 piece on 'tokenmaxxing' argued that developers obsessing over token efficiency are often making themselves less productive, not more. Willison's tool lands directly in that debate by giving developers concrete data to audit their assumptions. Meanwhile, the Codex competitive pressure covered in The Verge's April 16 piece means Anthropic needs Claude's pricing story to hold up under scrutiny: if Opus 4.7's tokenizer changes shift effective costs upward for common coding prompts, that is a real talking point for OpenAI's sales motion, not just a developer footnote.

Watch whether Anthropic publishes a formal tokenizer migration guide or cost-impact estimate for Opus 4.7 within the next 60 days. If they don't, third-party tooling like Willison's will define the narrative around the cost delta, and that's a position Anthropic should not want to cede.