Skip to content
GenAI BR
Cinco · weekly edition · Tuesdays, 7am BRT
Cinco no. 1Tuesday, 8 September 2026draft

The scissors: the frontiergot pricier and theopen model became pennies

Opening

In 2023, the most capable model in the world charged US$ 60 per million output tokens. In April 2025 it charged US$ 8. Last Thursday, GPT-6 Astra shipped at US$ 50 — the same price as Claude Fable 5.1, and two and a half times the model OpenAI launched in June. In the same two-week window, Z.ai put a 320-billion-parameter model, MIT-licensed, served according to the company only on Chinese chips, at US$ 0.50. The distance between the two ends is a hundredfold. That is what we call the scissors: the blades move apart, and what sits between them is the entire market of people who build with AI.

This edition's thesis is simple to state and hard to accept: price per token has stopped being the variable that decides between closed and open. For agentic work — code, terminal, operating systems — permissive open models have reached a capability band where the buying decision now depends on three other things: whether the model works in your domain (and the benchmarks every launch cites do not say), whether you can trust what it says it is thinking (GPT-6's own report says less and less), and where it runs (which, in Brazil, has become a R$ 959 million tender due on 8 October).

The five movements below follow that order: the weight of open weights, the price, the benchmark that no longer separates, the reasoning that will not be read, and the seven thousand petaflops of Macaíba. Each has a chart or a piece of executed code; the numbers are in the tables; the sources, numbered at the end. If you only have time for one: the second.

Read and written by João Campista · 21 min read

The five movements

  1. I
    Open models

    The weight of the weights

    Tencent published a 770-billion-parameter mixture-of-experts under Apache 2.0. It costs to run like a 49-billion model — and needs memory for all 770. “Open”, at this size, is a word with an owner.

    1 figure · 1 code
  2. II
    Infra and cost

    Fifteen cents

    The closed frontier is back to what it cost in 2023. The open model that trails it closely costs a hundredth of that. The list price has become a positioning signal — and stopped being a measure of cost.

    2 figures · 1 code · 1 table
  3. III
    Evaluation

    The number that no longer separates

    SWE-bench Verified went from 33% to 96% in two years and stopped telling models apart. A Fudan group collected 119 real bugs from scientific software: the best agent solves fewer than half — and, with that sample, the top five are statistically the same.

    2 figures · 1 code
  4. IV
    Product · Interpretability

    Reading the reasoning

    GPT-6 Astra reset the ceiling of nearly every benchmark OpenAI chose to show. The system card, read to the end, says something else: chains of thought got shorter, and the company will have “significantly reduced confidence” in detecting some misaligned behaviors.

    1 figure · 1 code
  5. V
    Regulation and Brazil

    Seven thousand petaflops

    After two years and three postponements, the Brazilian AI Plan's supercomputer has become a tender: R$ 959 million, 7,200 PFLOPS in FP16, Macaíba (RN), bids due 8 October. It is the first step with a number, a deadline and a document. It is also smaller, in money and in megawatts, than the plan promised.

    1 figure · 1 code · 1 table

Get the next Cinco

Tuesday, 7am BRT, in your inbox. Five items, with sources. No daily newsletter, no promotions, and unsubscribing is one click.

Just the e-mail. No third-party trackers on this page. Privacy policy.

What we're building

Archive by theme

Archive→
  1. Open models5

    Open weights, licenses, technical reports and what you can run yourself.

  2. Agents7

    Systems that plan, use tools and act — and how to tell when they work.

  3. Evaluation7

    Benchmarks, contamination, leaderboards and the gap between the score and real use.

  4. Interpretability3

    What happens inside the model: features, circuits, chain-of-thought faithfulness.

  5. Infra and cost5

    Inference, GPUs, price per token, and what changes when cost drops tenfold.

  6. Multimodal2

    Image, audio, video and text in the same model — and what it costs.

  7. Regulation and Brazil3

    PL 2338, ANPD, PBIA, the labor market and what is happening with AI here.

  8. Product4

    Launches, pricing, APIs and product decisions that change what can be built.

Who reads for you

Today, one person: João Campista, in São Paulo. I read a couple of hundred things a week and pick five. Triage is AI-assisted; the reading, the judgment and the writing are mine.