Where Opus, Sol, And Jev Fit In My AI Workflow
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🔍 Read the full analysis: Where Opus, Sol, And Jev Fit In My AI Workflow on ThorstenMeyerAI.com

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TL;DR

Thorsten Meyer’s Sept. 29 workflow assigns Opus 5.5 to building, GPT-6.1 Sol to detailed review and Jev to high-volume yes/no decisions. The approach reflects a reported gap in task costs among models with relatively close benchmark scores, though the figures come from one index and may not predict performance on individual workloads.

Thorsten Meyer said on Sept. 29 that he uses Claude Opus 5.5 to build software, newly released GPT-6.1 Sol to inspect details and review changes, and Jev for high-volume yes-or-no and routing decisions. His workflow reflects a reported spread in model costs: the Artificial Analysis Intelligence Index v4.3.x lists six models within about 20 points of one another, while their cost per task varies by roughly 100 times.

Meyer’s reported default for development is Opus 5.5 at high effort, which the index scores at 54 and prices at $1.82 per task. He uses xhigh for harder work such as architecture, migrations and trust boundaries; that setting scores 56 at $3.46 per task. He says he rarely uses max effort, which scores 58 but costs $5.98 per task.

For a second review, Meyer uses GPT-6.1 Sol at high or xhigh. The index lists those settings at 50 points and $0.32 per task, and 51 points and $0.39 per task, respectively. Meyer says he assigns Sol focused reviews of files or code changes, rather than asking it to build. Its high and xhigh settings have reported times to first token of 57 and 69 seconds, making them less suited to interactive use.

The workflow assigns other models narrower roles: Sonnet 5.5 for scoped subtasks and documents, Astra or Fable for a second opinion when models disagree, and Luna for classification, extraction and routing. Meyer describes Jev as a decision model that cannot write sentences, used for routine yes-or-no and routing judgments. The source does not give Jev a score, price or release date.

At a glance
reportWhen: Published Sept. 29, 2026; GPT-6.1 Sol w…
The developmentThorsten Meyer published a model-by-model AI workflow on Sept. 29, pairing Opus 5.5 for development with GPT-6.1 Sol for review and Jev for routing decisions.

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.

A Review Pass at Lower Cost

The workflow treats model choice as a question of quality at a given task cost, rather than picking one model for every job. If Meyer’s reported prices and scores hold for his workload, assigning routine review to a lower-cost model could make it practical to check more changes. He says a different model family reviewing Opus’s output provides a useful second perspective, while acknowledging that two models can still share a flawed specification.

The figures also suggest that the effort setting can materially affect cost. On the index, Opus 5.5 rises from 51 points and $1.34 per task at medium to 58 points and $5.98 at max. Those are benchmark results, not a guarantee that the most expensive setting will produce proportionately better outcomes for a particular team. Meyer’s advice to shadow-test before switching systems recognizes that distinction.

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The Index Behind the Workflow

The source attributes its model scores and task costs to the Artificial Analysis Intelligence Index v4.3.x, describing it as a general capability measure rather than a verdict on any one workload. Its Sept. 29 snapshot lists Opus 5.5 at 58 points and $5.98 per task at its top setting; GPT-6.1 Sol at 51 and $0.39 at xhigh; and Luna at 37 and $0.07. The reported figures use the index’s task-cost estimates, not simply token prices.

Meyer also reports that GPT-6.1 Sol launched Sept. 29 at the same stated token prices as GPT-6 Sol: $2 per million input tokens and $10 per million output tokens. He says Sol’s medium setting scores 48 at $0.21 per task. These are figures cited in the source article; the material provided does not include independent measurements of Meyer’s own workloads.

“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

Workload Results Remain Unverified

The source does not provide controlled comparisons of these models on the same software tasks, nor does it show how often Sol catches defects in Opus’s work. Index scores and estimated task costs may differ from results in a reader’s own workflow. Meyer recommends shadow-testing before a switch, but the article does not report the results of such a test.

Some benchmark details are also incomplete. According to the source, Artificial Analysis had not published GPT-6.1 Sol’s low or max settings, and a one-point difference falls within measurement noise. Jev’s pricing, capabilities beyond the stated decision role, and evaluation results are not supplied. The source material also ends partway through a cost example, so it does not establish a complete comparison of model costs with human review time.

Test the Split on Real Tasks

Meyer’s stated next step for teams considering a similar setup is to shadow-test models on their own work before changing defaults. That means checking whether the models meet a team’s quality requirements and whether review savings persist once human oversight is included. The source does not announce a formal rollout, a follow-up benchmark date or further details about Jev.

For now, the workflow is Meyer’s account of how he uses the models as of Sept. 29, 2026. Readers should treat the reported prices, settings and scores as a dated snapshot; the material does not say when those figures will next be updated.

Key Questions

What does Meyer use Opus 5.5 for?

He uses Opus 5.5 at high effort for feature work, APIs, multi-file changes and refactors. He reserves xhigh for harder tasks such as architecture and migrations.

What role does GPT-6.1 Sol play?

Meyer uses GPT-6.1 Sol for detailed inspection and review, including focused checks of files and code changes. He says its lower reported task cost makes routine review more practical for his workflow.

What is Jev, according to the source?

The source describes Jev as a decision model that cannot write sentences. Meyer uses it for high-volume yes-or-no judgments and routing; the source gives no score or price for it.

Are the reported scores proof these models will work best for every team?

No. The scores come from the Artificial Analysis Intelligence Index v4.3.x, which the source characterizes as a general capability measure. Meyer advises testing models on a team’s own workload before switching.

Source: ThorstenMeyerAI.com

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