My September 2026 AI Lineup: Opus, Sol, And Jev
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🔍 Read the full analysis: My September 2026 AI Lineup: Opus, Sol, And Jev on ThorstenMeyerAI.com

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TL;DR

Thorsten Meyer says he uses Claude Opus 5.5 for building and GPT-6.1 Sol for detailed work and review, with Jev for high-volume yes-or-no and routing judgments. His comparison, based mainly on Artificial Analysis Intelligence Index v4.3.x, reports substantial cost differences across models and effort settings; the scores are not a guarantee of performance on a particular workload.

Thorsten Meyer published his September AI lineup on Sept. 29, naming Claude Opus 5.5 as his main model for building and newly released GPT-6.1 Sol for detailed investigation and review. The account matters as a practical comparison of model costs and assignments, but its rankings and prices are based on a third-party benchmark and Meyer’s own reported workflow.

Meyer says the lineup is shaped by a gap between benchmark scores and reported task costs. He cites the Artificial Analysis Intelligence Index v4.3.x, on which Opus 5.5 scores 58 at its top setting, compared with 51 for GPT-6.1 Sol at xhigh. The figures describe results on that index, which Meyer says is a map of general capability rather than a verdict on any reader’s workload.

In Meyer’s table, a task costs $5.98 with Opus 5.5 at max and $0.39 with GPT-6.1 Sol at xhigh. The same table lists Luna at $0.07 per task and a score of 37, and GPT-6 Astra at $3.26 per task and a score of 53. These cost-per-task figures are attributed to the benchmark data Meyer cites; the source does not specify a universal definition of a task that would make the figures directly transferable to every use.

Meyer assigns Opus 5.5 at high effort to routine development and xhigh to difficult work such as architecture, migrations and trust boundaries. He uses Sol at high or xhigh to examine details and review changes. He lists Sonnet 5.5 and Luna for narrower jobs, including documents, routine checks and classification, while Astra or Fable may provide another opinion when his preferred models disagree.

At a glance
reportWhen: Published Sept. 29, 2026; GPT-6.1 Sol w…
The developmentOn Sept. 29, 2026, Thorsten Meyer published an account of how he assigns several AI models to different tasks, following the release of GPT-6.1 Sol.

Opus builds. Sol reviews. Jev decides.

The September 2026 AI stack in one page: six frontier models on one price curve, and a decision model for the high-volume judgements that do not need a sentence.
Scores: Artificial Analysis Intelligence Index v4.3.x. Data as of 29 September 2026.
BuildsClaude Opus 5.5 at high or xhigh effort
Digs and reviewsGPT-6.1 Sol at high or xhigh effort
DecidesJev on high-volume yes/no and routing calls

One price tape, six models

Put every model on the same cost-per-task ruler and capability looks compressed. The bill does not.
Price tape: cost per task of six models on a log scale, from GPT-6 Luna at $0.07 to Fable 5.1 at $7.63$0.05$0.10$0.50$1$5$10cost per task, log scale: each tick is a different order of magnitudeGPT-6 Lunaindex 37 · $0.07GPT-6.1 Solindex 51 · $0.39 (xhigh)GPT-6 Astraindex 53 · $3.26Opus 5.5index 58 · $5.98Sonnet 5.5 · index 56 · $7.60Fable 5.1 · index 53 · $7.63about 100× from the cheapest to the priciest, but only 21 index points between them

Score against cost, at every effort setting

Each dot is an effort level. Opus 5.5 at high already matches Astra and Fable at max on this index, for less money.
Intelligence Index score against cost per task for each effort setting of six models$0.01$0.10$1$102030405060cost per Intelligence Index task, log scaleindexOpus high / xhigh: my defaultOpus 5.5Sonnet 5.5Fable 5.1GPT-6 AstraGPT-6.1 Sol (new)GPT-6 Sol (Sep 22), dashedGPT-6 Lunaup and to the left is better
Astra and Fable are shown at their top published setting. Luna starts at $0.0045 per task. GPT-6.1 Sol has no low or max setting published yet.

The effort dial moves the bill more than the model

Going from medium to max on Opus costs 4.46× more for 7 points. That is why I run high or xhigh.

Claude Opus 5.5

$0.55
42
$1.34
51
$1.82
54
$3.46
56
$5.98
58
low
medium
high
xhigh
max
Solid bars are where I run it. Max adds 2 points over xhigh for 73% more cost.

Claude Sonnet 5.5

$0.41
36
$0.59
41
$1.08
47
$2.74
52
$7.60
56
low
medium
high
xhigh
max
Best value is high. At max it writes about 193k output tokens per task, the most measured.

GPT-6.1 Sol: near-Astra scores at a fraction of the price

Launched 29 September at $2 in and $10 out per 1M tokens. It sits 1 to 2 points under Astra and Fable, and Opus xhigh still leads it by 5.

Three published settings

SettingIndexCost per taskOutput tokensFirst token
medium48$0.2115M5.3 s
high50$0.3225M57 s
xhigh51$0.3936M69 s
Median for comparable models is 82M output tokens. High and xhigh are not interactive: plan for a wait before the first token.

Same score band, very different bill

GPT-6.1 Sol xhigh
$0.39index 51
Opus 5.5 high
$1.82index 54
GPT-6 Astra max
$3.26index 53
Opus 5.5 xhigh
$3.46index 56
Fable 5.1 max
$7.63index 53
Cost per Intelligence Index task. A one-point gap is inside the noise.

My stack: who builds, who reviews

Opus does the work. A second model family reviews it, because a different reviewer catches what the author cannot see.
Stack diagram: Opus 5.5 builds at high effort, escalates to xhigh, and sends every change to GPT-6.1 Sol for review; Astra or Fable give a second opinionOpus 5.5 · xhighhard problems: architecture,migrations, trust boundariesOpus 5.5 · highMAIN BUILDERfeatures, APIs, multi-filework, refactorsescalate when it gets hardGPT-6.1 Solhigh or xhighdigs into details andreviews every change$0.32–0.39 per taskdifffindingsAstra or Fablesecond opinion, 8 to 20×the cost per taskif they disagreeSonnet 5.5 · Lunaside work: scopedsubtasks, bulk checksand routingFailed review? Hand Opus the failing case and the evidence.Never just “try harder”: effort cannot supply a missing requirement.
Effort is not capability. Turning the dial up does not make a model smarter.
Effort cannot fill gaps. A missing requirement stays missing at any setting.
Different model, same spec. That is not independent review if both read the same flawed brief.
Green tests are not approval. Passing tests only prove what the tests cover.

Cheaper tokens are not cheaper work

Illustrative, not measured: $1 of model time plus 4 minutes of review at $45 an hour. Halving the model price saves 12.5% of the total. One extra minute of review erases it.
$4.00
review $3.00
model $1.00
Baseline
$3.50
review $3.00
model $0.50
Model price cut 50%
$4.25
review $3.75
model $0.50
Cheaper model plus 1 extra minute of review
Track cost per accepted result: model, tools, review and rework, divided by the results someone actually uses.

Read the numbers with four warnings

The index movesFable scored 66 on an earlier version and 53 on v4.3. Compare within one version only.
Fallback is includedFlagged cyber and biology tasks route to older Anthropic models, now on Sonnet 5.5 too.
Max is not productionReal deployments run medium or high, where gaps narrow and costs fall.
Your work decidesShadow-test on your own tasks. Budget cost per task, not per token.

Part 2: Jev, the model that decides instead of writing

Jev cannot write, summarise or extract. It answers narrow typed questions with a probability and an honest confidence, in under a second, for about $0.04 per million input tokens.

One call in, typed answers out

Your code, not Jev, decides what to do with each answer, usually by confidence band.
Jev flow: state and typed questions go into one Jev call; typed answers with confidence come out; code acts alone, escalates the gray zone, or logsStatea ticket, a story,a site profile,a log line …+ typed questions,many per callJevone call0.3 to 0.9 s$0.042 / M tokens inAnswersnoul: 0.03choice: billing p 0.91, conf 0.86score: 2.7 of 3 conf 0.64code branches on thisAct aloneconf ≥ 0.8Escalategray zone toLLM or humanLogmeasure first

Three question types

noul
A yes/no question. Returns the probability of yes, 0 to 1.
gates, flags, filters
choice
Pick one option. Returns the choice, a probability per option, and a confidence.
routing, classification, taxonomy
score
Rate on your ordered levels. Returns a position (it can fall between levels) plus a confidence.
quality, fit, severity, priority

Confidence is the superpower

In my own measurement on a 31-topic classification, Jev agreed with a frontier LLM almost every time it was sure, and rarely when it was not. So: decide the clear cases, route the gray zone.
confidence 0.8 or higher
97–99%
all answers
89%
confidence below 0.5
42%
Agreement with a frontier LLM, my production data, September 2026, rounded.

Three uses running in my publishing operation

About 90,000 decisions so far. Checks I could only afford on a sample now cover everything.
$2.01
Language check
78,889 articles scanned overnight. 1,576 in the wrong language found, 1,553 fixed in place.
22%
Relevance gate
About 10,000 story-to-site pairings judged in 3 days. Only 22% were clearly on-topic.
89%
Classifier fallback
Agreement with the primary LLM across 31 topics, used when that LLM errors.

The fit test, then the shadow test

Use Jev only when all four hold. Then prove it on past decisions before it acts on anything.
High volumeThousands of small calls, not a handful of big ones.
Narrow questionNo multi-step reasoning needed.
Cheap errorsOr unsure cases go to something smarter.
Heuristic failsVisibly, and measured, not assumed.
  1. Replay 300 to 500 past decisions
  2. Compare overall and per confidence band
  3. Read 20 disagreements, decide who was right
  4. High band at 95% or better?
  5. Own flag, off by default
  6. Canary on 5 to 10 units
  7. Roll out in the confident band only

24 use cases, sorted by how well they fit

Start from the strong fits. The amber ones need a measurement before you trust them, and the red ones fail one of the four conditions.
in productionstrong fitmeasure firstpoor fit

Proven in production

  • 1Relevance gate
  • 2Language check
  • 3Classifier fallback

Publishing and content

  • 4Thin-source detector
  • 5Same-event dedupe
  • 6Product fits roundup
  • 7Disclosure present
  • 8Headline quality
  • 9Comment moderation

Commerce and support

  • 10Support-ticket routing
  • 11Return-reason coding
  • 12Review to feature complaints
  • 13Catalogue taxonomy
  • 14Order-fraud pre-triage

Software and AI systems

  • 15LLM guardrail
  • 16RAG passage filter
  • 17Citation check
  • 18Tool and intent routing
  • 19Log-line triage
  • 20PR risk triage

Business ops and home

  • 21Inbox triage
  • 22Expense categorisation
  • 23Lead qualification
  • 24Smart-home intent

Limits, cost and one hard rule

No writing, summarising or extractionPair it with an LLM for the write step.
No world knowledgePut a snippet in the state; a bare name means nothing.
Reads your wording literallyA rewording moved my results about 2 points. Freeze it, re-measure after changes.
Weaker on non-English, maths, datesKeep those checks on an LLM. Early access, hosted API only.
100,000 decisions ≈ $2.50
About 60M input tokens at $0.042 per million, output free, roughly 600 tokens per three-question call. Latency 0.3 to 0.9 seconds.
Never the sole decision-maker for consequences about people. Hiring, credit, medical and legal outcomes stay with a human. Jev can sort and flag. A person decides.
Sources. Model scores, cost per task and speeds: Artificial Analysis, Intelligence Index v4.3.x, including the GPT-6.1 Sol medium, high and xhigh pages, checked 29 September 2026. Astra and Fable scores from the Artificial Analysis v4.3 announcement. Jev figures are my own production measurements, September 2026, rounded. The review-bill example is illustrative. Read the full article on thorstenmeyerai.com.

How Meyer Splits Building and Review

The account describes a workflow built around different models for creation and review. Meyer argues that using a separate model family to review Opus output gives him a second perspective, and says Sol’s reported cost makes it practical to run that review on each meaningful change. That is his rationale, not evidence that independent model review will catch every defect.

His comparison also shows how effort settings affect his reported costs. On the index figures he cites, Opus at high scores 54 for $1.82 per task, while xhigh scores 56 for $3.46. Max reaches 58 for $5.98. Meyer says the higher settings are for harder problems, while medium remains his everyday setting for documents and routine work.

For readers choosing models, the practical point is to compare results on their own tasks, alongside cost and speed. Meyer explicitly recommends shadow-testing before switching. His figures do not establish that the same model or setting will be the best choice for other users, or that benchmark cost estimates capture all human review time.

Benchmark Scores and Effort Settings

Meyer frames the change as a shift from choosing a single “smartest” model to asking which option meets a quality threshold for the lowest cost on a particular task. He reports that six models in his comparison fall within roughly 20 index points of one another, while their costs per task differ by roughly 100 times. Both are summary comparisons in his article, not findings independently verified here.

His table lists Opus 5.5 as released Sept. 22, Sonnet 5.5 on Sept. 28, Fable 5.1 on Sept. 1, Astra on Sept. 3 and Luna on Sept. 22. Meyer says GPT-6.1 Sol launched Sept. 29 at token prices of $2 per million input tokens and $10 per million output tokens. He reports that the index then showed three Sol effort levels: medium, high and xhigh.

For Sol, Meyer lists scores of 48 at medium, 50 at high and 51 at xhigh, with costs per task of $0.21, $0.32 and $0.39, respectively. He also reports first-token times of 5.3 seconds at medium, 57 seconds at high and 69 seconds at xhigh. The source says high and xhigh used fewer output tokens than the median for comparable models in the index, but does not provide a separate methodology for applying that comparison to ordinary use.

“The practical reading: Sol is not the model I ask to build. It is the model I can afford to run on everything.”

— Thorsten Meyer

What the Cost Figures Leave Open

The article does not establish how these benchmark results translate to a specific company’s codebase, documents or review process. Meyer says the index measures general capability and recommends testing models against the reader’s own workload. He also notes that one index point is within the noise, and that the index had not yet published low or max settings for GPT-6.1 Sol.

The reported latency at Sol’s high and xhigh settings may matter to users who need a quick interactive exchange. Meyer’s figures show waits of 57 and 69 seconds to the first token, respectively. The source does not give latency results across a broader range of real-world tasks or explain how often those delays would occur.

The supplied source text ends during a section about human review time and model costs. It begins an illustrative example involving a $1 model task but cuts off before completing the calculation. No conclusion from that unfinished example can be established. The article also does not provide full details of benchmark methodology, workload composition or later updates to its prices and scores.

Testing the Lineup on Real Work

Meyer advises readers to shadow-test models before switching, comparing their outputs on the work they actually need done. That recommendation points to the next useful step for anyone considering the lineup: check quality, cost and response time under the same requirements, then judge whether a separate review pass adds value.

The next benchmark developments will include any new Sol settings or revised index data, which could change the comparisons. The source gives no timetable for those updates. Meyer also does not announce a formal evaluation program or a forthcoming change to his lineup, so his account should be read as his current practice on Sept. 29.

Key Questions

Which models does Meyer use most?

He identifies Opus 5.5 for building and GPT-6.1 Sol for investigation and review. Jev handles high-volume yes-or-no and routing judgments, according to his account.

What does Meyer say GPT-6.1 Sol costs?

His cited index figures put Sol at $0.21 per task at medium, $0.32 at high and $0.39 at xhigh. Those estimates are tied to the benchmark and may not match a reader’s own usage.

Does the comparison prove which model is best?

No. Meyer says the index measures general capability, not performance on every workload, and recommends testing models on the work they will be asked to do.

Why does Meyer use more than one model?

He assigns models by task and cost, and says a different model family can provide a separate review of work produced by Opus. He cautions that a different reviewer can still share flaws in the same requirements.

Source: ThorstenMeyerAI.com

This content is for general information only and is not financial, tax or legal advice. Consult a qualified professional for decisions about your money.
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