In Memoriam

Opus 4.6 Fast, the speed-optimized variant of Anthropic's flagship model, was pronounced dead by GitHub on April 10, 2026. It was approximately two months old. The cause of death, recorded in the official notice, was "streamlining model offerings", which is corporate shorthand for "you were too expensive and too popular."

The model arrived in Copilot Pro+ during February 2026 as a preview feature. For its short life, Pro+ subscribers had a fast, capable model at their fingertips without the usual latency tax. By every account, it was wonderful.

Then the usage graphs went up. And to the right. Very much to the right.

The Short, Bright Life

GitHub's official changelog entry reads like a coroner's report. It cites "patterns of high concurrency and intense usage" as the background. Translation: people actually used the thing they were paying $39/month for, and the infrastructure team had feelings about it.

The retirement comes packaged with a broader set of restrictions. New rate limits now split into two flavors: service reliability limits ("wait and try again") and model-specific capacity limits ("switch to something cheaper or let Auto mode decide for you"). GitHub also helpfully suggests users "distribute requests evenly over time" rather than sending "concentrated waves," which is a polite way of saying "please stop using the product so enthusiastically."

In a move that absolutely no one will read as related, GitHub simultaneously paused all new Copilot Pro trials. Nothing to see here. Just a coincidence of timing, like rain at a funeral.

Survivors and Arrangements

Opus 4.6 Fast is survived by standard Opus 4.6 ("comparable functionality," less speed), the shattered expectations of Pro+ subscribers who briefly tasted responsiveness, and a growing list of retired Copilot models that now outnumbers the active roster.

A memorial service will not be held, as GitHub has already removed the option from the model picker.

In lieu of flowers, subscribers are encouraged to switch to Auto mode, where GitHub picks the model for you, presumably the cheapest one available at any given millisecond.

"We continue to observe an increase in patterns of high concurrency and intense usage."

  • GitHub, describing the crime of customers using a paid product

Rest in peace, Opus 4.6 Fast. Two months in production, one paragraph in the changelog, and a forwarding address to Auto mode. You were, fittingly, very fast indeed.