A Closer Look At My September 2026 AI Workflow
AIThis post was created with the assistance of artificial intelligence (AI).

🔍 Read the full analysis: A Closer Look At My September 2026 AI Workflow on ThorstenMeyerAI.com

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TL;DR

Thorsten Meyer’s Sept. 29 account describes a workflow that uses Claude Opus 5.5 for most software building and newly released GPT-6.1 Sol for detailed review. His model comparisons use Artificial Analysis Intelligence Index v4.3.x scores and estimated cost per task; he says teams should test models on their own work before switching.

Thorsten Meyer said on Sept. 29 that he uses Claude Opus 5.5 for most software building and the newly released GPT-6.1 Sol for detailed work and review, reflecting a workflow organized around estimated cost per task as well as benchmark scores. His figures draw on the Artificial Analysis Intelligence Index v4.3.x; he cautioned that the index measures general capability, not performance on a particular team’s workload.

Meyer’s comparison lists Opus 5.5 at 58 on the index’s top setting and an estimated $5.98 per task. GPT-6.1 Sol scores 51 at xhigh for $0.39 per task, while GPT-6 Astra scores 53 at its top setting for $3.26. Claude Fable 5.1 scores 53 for $7.63, Sonnet 5.5 scores 56 for $7.60, and GPT-6 Luna scores 37 for $0.07. The source does not provide a full methodology for those per-task estimates in the supplied material.

For development, Meyer places Opus at high effort by default: the source lists that setting at 54 index points and $1.82 per task. He reserves xhigh for work such as architecture, migrations and trust boundaries, at 56 points and $3.46. He assigns Sol high or xhigh to focused examination of files and code changes, and to a second review pass.

The source reports that GPT-6.1 Sol launched Sept. 29 at $2 per million input tokens and $10 per million output tokens. Its index figures range from 48 at medium to 51 at xhigh, with reported first-token times of 5.3 seconds, 57 seconds and 69 seconds at medium, high and xhigh, respectively. Meyer says he uses Sonnet 5.5 and Luna for narrower tasks, while Astra or Fable may provide another opinion when models disagree.

At a glance
reportWhen: Published Sept. 29, 2026; GPT-6.1 Sol r…
The developmentThorsten Meyer published a Sept. 29 account of how he assigns AI models to software development and review based on benchmark scores and estimated task costs.

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 Task Costs Shape Model Choice

Meyer’s account illustrates a practical change in how some developers evaluate AI models: they may weigh the cost of completing a task alongside benchmark performance. In his figures, Sol xhigh costs $0.39 per task, compared with $3.26 for Astra at its top setting and $7.63 for Fable 5.1. Those estimates could make a second model review more feasible to run routinely, though the source does not establish that other users will see the same costs or results.

He also argues that higher effort settings can raise bills substantially for small score gains. On Opus 5.5, moving from xhigh to max adds two index points and increases the listed cost per task from $3.46 to $5.98. Such comparisons matter to teams choosing defaults, but they do not show which model will perform best on a specific codebase or task. Meyer recommends shadow-testing against existing workflows before switching.

Benchmarks Behind the Workflow

The figures cited by Meyer come primarily from the Artificial Analysis Intelligence Index v4.3.x, which he describes as a map of general capability rather than a verdict on an individual workload. The source gives model release dates ranging from Fable 5.1 on Sept. 1 to GPT-6.1 Sol on Sept. 29, with Opus 5.5 listed as released Sept. 22 and Sonnet 5.5 on Sept. 28.

His account distinguishes token prices from estimated task costs. It lists per-million-token prices of $4/$20 for Opus, $10/$50 for Fable and Astra, $2/$10 for Sol, and $0.10/$0.50 for Luna, in input/output order. Task costs vary with effort and output length, so the token price alone does not capture the expense of a given task.

““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

Limits of the Published Comparisons

The figures are benchmark results and cost estimates cited by Meyer, not evidence that every user will obtain the same quality, latency or cost. The source notes that one index point is within the noise and says low and max effort results for GPT-6.1 Sol had not yet been published. It also reports long first-token times at Sol’s high and xhigh settings.

The supplied account cuts off during an illustrative example about model prices and human review. It therefore does not provide the full calculation or its assumptions. The material also does not say how the estimated task costs were derived beyond identifying the index and listing token prices and output figures.

Testing Models on Real Work

Meyer’s next recommended step for teams is to shadow-test models on their own tasks before changing defaults. That would let developers compare quality, latency, review effort and cost against the work they actually need done. The source does not announce a scheduled follow-up or a date for additional benchmark results; GPT-6.1 Sol’s low and max settings remained unlisted in the account.

Key Questions

What model does Meyer use for building?

He names Claude Opus 5.5 at high effort as his main model for development, with xhigh for harder work such as architecture and migrations.

What role does GPT-6.1 Sol play in his workflow?

Meyer uses Sol at high or xhigh for focused inspection and independent review. He says the listed cost is $0.32 to $0.39 per task at those settings.

Are these benchmark scores proof that one model is best for every team?

No. Meyer describes the index as a measure of general capability, not a verdict on a team’s workload, and recommends shadow-testing before switching.

What remains unknown about GPT-6.1 Sol’s benchmark results?

In Meyer’s Sept. 29 account, the index had not yet published Sol’s low or max effort results. He also says high and xhigh have long reported first-token times.

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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