At the end of September…
A mystery model known as Pixel Canary appeared on Vercel AI Gateway.
On October 1, it removed the mask in Scooby-Doo fashion and turned out to be Callstack.
And we would have gotten away with it too, if it weren’t for you meddling benchmarkers!
Pixel Canary is Apex, a coding model designed for everyday agent tasks, and it is now available to the public.
The model is particularly strong in React Native and Next.js, which is either a coincidence or the most transparent flex since someone named a crypto coin after themselves.
What did it build while it was undercover?
During the stealth week, Michał Pierzchała (@thymikee) asked it to cook “something” overnight in OpenCode and came back to a SpaceX launch tracker… which is the agentic equivalent of leaving a teenager alone with DoorDash and finding a Michelin reservation.
It's called Orbit Watch, featuring a Skia globe, Reanimated worklets and native tabs on Expo 57, and it used agent-device (an open-source CLI that lets AI agents control and test your app on iOS and Android devices) to verify its own work.
Pixel Canary got through over 200 billion tokens in just five days.
But… is it any good?
On the React Native evals, it lands within a point of Claude Opus 5.5 and outperforms GPT-6.1 Sol, all at about a quarter of the cost of a full Opus run.
On the Next.js evals carried out by Vercel, it completed 28 out of 31 tasks, matching GPT-6 Astra on high effort, and 30 out of 31 with the Next.js docs in AGENTS.md.
Reading the docs still works… who would have guessed!?
Callstack also tested code review on the Expensify repo using both Apex and Opus 5.5.
It's one run only, not a benchmark, but the fact that it's six times faster and 85% cheaper is difficult to ignore…
Unless your personality is powered exclusively by vendor lock-in.
What does it cost, and how do we use it?
The rate is 50 cents per million input tokens, 20 cents for cached input and $3.00 per million output tokens, compared to $20 per million output tokens for Opus 5.5.
It has a 256K context window and an API that is compatible with both OpenAI and Anthropic, enabling tools such as Claude Code, Cursor and Codex to use it without rewriting your entire religion.
Run:
npx @callstack/apex init
And it will locate the coding tools on your machine and point them at Apex.
In the past, canaries were sent down the mines to warn the miners when there was a problem.
This one goes into your codebase…
The only warning it gives is about your Opus bill.
And hopefully you don’t find it dead after a few hours of intense work,
👉 Apex
Want the rest of The Agentic Rewind #1? Part 2 covers OpenAI's beret-wearing Dots, plus this week's pack of agent links (GPT-6.1 Sol, Claude Sonnet 5.5, Pi 1.0 and more).
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This is #Part1 of The Agentic Rewind #1. Read the full issue here.
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