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NaHero’s reported experience shows why matching labels across translated exam questions is a separate problem from generating labels in the first place. Its builder says two independently tagged language versions of a Google Workspace Admin exam agreed on domain labels only about 73% of the time on the first pass. The reported fix—tag in one language, then copy those labels to the translation—makes paired results consistent by construction, but does not prove the labels are correct.
What NaHero was labeling
In a DEV Community article published October 6, 2026, builder Mateus described NaHero as a timed practice-exam service for AWS, Azure, and Google Cloud certifications. The article reports a bank of about 8,700 questions across 30 exams, with each exam available in Brazilian Portuguese and English. The figures and implementation details here are the builder’s account, not independently audited results. Read the source article on DEV Community.
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The labels matter because NaHero uses per-domain results to tell learners what to study. If equivalent Portuguese and English exams attach different domains to questions, two users can receive different study guidance even when they answer equivalent material.
How the first-pass tagging worked
Mateus says the questions were labeled in batches of 40 using claude -p, Claude Code’s non-interactive mode. Each prompt included the domain list for the relevant exam, and the output labels were checked against that fixed list. That closed set prevents the model from freely inventing domain names, although it cannot by itself establish that a chosen label is semantically right.
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The article estimates that labeling the full bank took about 220 calls. The builder then independently tagged Portuguese and English versions and compared the results. For Google Workspace Admin, the first-pass labels agreed about 73% of the time. That is a consistency measurement between two runs—not an accuracy score against human-verified ground truth. The article reports no such ground truth or post-change accuracy result.
Why the language versions disagreed
Translation does not remove ambiguity from a classification task. A question may touch multiple domains, or a term may suggest different interpretations depending on the exam’s domain taxonomy. A prompt that gives the model a list of allowed labels constrains its choices, but broad or overlapping labels still leave room for inconsistent decisions across languages.
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The source describes two interventions, not a controlled comparison. Their implications differ:
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| Add exam-specific disambiguation lines, such as “billing and pricing” | Clarifies how a potentially ambiguous domain should be interpreted within that exam. | The article reports no measured post-change agreement or accuracy score. |
| Tag the English version, then copy those labels to Portuguese | Ensures paired language versions carry the same labels, avoiding disagreement caused by separate tagging. | Matching labels do not demonstrate that the source-language labels are correct or that they fit the translated question. |
The builder’s own qualification is central: “The first change still matters, because agreement alone doesn’t make the English tag correct.” Choosing one language as the source of truth solves a consistency problem operationally. It does not independently verify the underlying classification.
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A practical way to measure and handle disagreement
NaHero’s reported approach suggests separating three questions that are easy to conflate:
- Are outputs valid? Check that every generated label belongs to the exam’s approved domain list.
- Are language versions consistent? Compare labels for paired translations, ideally using a fixed set of questions and the same taxonomy.
- Are labels correct? Compare against a human-reviewed reference set or another explicit quality process. Agreement between model outputs alone cannot answer this.
When disagreement appears, the reported interventions offer distinct levers: clarify domain boundaries in the prompt, or make one language’s labels authoritative and propagate them to its translation. The first targets ambiguous instructions; the second prevents independent runs from drifting. Neither should be presented as a demonstrated accuracy improvement based on the reported figures.
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Why separate calculations from generated study advice
The same article describes a study-plan pipeline that keeps numeric work out of the prose-generation step. SQL computes hits by domain, missed questions, and prior scores; DeepSeek V4.1 Flash then receives those values and returns JSON text. The product checks that returned domain names match the input and disallows links. According to Mateus, it stores a plan once per attempt, including failures, to avoid repeatedly generating it.
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What the product figures do—and do not—show
As of October 6, 2026, Mateus reported about 95 registered users, roughly 75% of them in Brazil, and around 30 signups per week with no ads running. These are early, product-specific figures, not benchmarks for exam-preparation services or LLM classification.
The article also says most CLF attempts scored between 23 and 47 out of 65, with passing described as around 46. About 15% of users took a second exam during their first week. A Google Ads test reportedly spent R$100 for 71 clicks, with click costs reported from R$0.31 to R$0.90, an 11% click-to-signup rate, and one annual subscriber; LinkedIn posts reportedly brought in three times what Google Ads did. The article does not establish these as general acquisition or learning outcomes.
NaHero’s reported free tier included all 30 exams, unlimited attempts, scores, domain results, and the ability to resume an attempt. Premium was listed at R$10 per month or R$90 per year and added explanations, a study plan, and practice questions on a user’s weakest domain. These are the product terms the builder reported for that date.
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