CAPITU: A Benchmark for Evaluating Instruction-Following in Brazilian Portuguese with Literary Context

Fuente: arXiv
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Main Authors: Bonás, Giovana Kerche, Junior, Roseval Malaquias, Piau, Marcos, Laitz, Thiago, Almeida, Thales Sales, Abonizio, Hugo, Larcher, Celio, Pires, Ramon, Nogueira, Rodrigo
Format: Preprint
Published: 2026
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author Bonás, Giovana Kerche
Junior, Roseval Malaquias
Piau, Marcos
Laitz, Thiago
Almeida, Thales Sales
Abonizio, Hugo
Larcher, Celio
Pires, Ramon
Nogueira, Rodrigo
author_facet Bonás, Giovana Kerche
Junior, Roseval Malaquias
Piau, Marcos
Laitz, Thiago
Almeida, Thales Sales
Abonizio, Hugo
Larcher, Celio
Pires, Ramon
Nogueira, Rodrigo
contents We introduce CAPITU, a benchmark for evaluating instruction-following capabilities of Large Language Models (LLMs) in Brazilian Portuguese. Unlike existing benchmarks that focus on English or use generic prompts, CAPITU contextualizes all tasks within eight canonical works of Brazilian literature, combining verifiable instruction constraints with culturally-grounded content. The benchmark comprises 59 instruction types organized into seven categories, all designed to be automatically verifiable without requiring LLM judges or human evaluation. Instruction types include Portuguese-specific linguistic constraints (word termination patterns like -ando/-endo/-indo, -inho/-inha, -mente) and structural requirements. We evaluate 18 state-of-the-art models across single-turn and multi-turn settings. Our results show that frontier reasoning models achieve strong performance (GPT-5.2 with reasoning: 98.5% strict accuracy), while Portuguese-specialized models offer competitive cost-efficiency (Sabiazinho-4: 87.0% at \$0.13 vs Claude-Haiku-4.5: 73.5% at \$1.12). Multi-turn evaluation reveals significant variation in constraint persistence, with conversation-level accuracy ranging from 60% to 96% across models. We identify specific challenges in morphological constraints, exact counting, and constraint persistence degradation across turns. We release the complete benchmark, evaluation code, and baseline results to facilitate research on instruction-following in Portuguese.
format Preprint
id arxiv_https___arxiv_org_abs_2603_22576
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle CAPITU: A Benchmark for Evaluating Instruction-Following in Brazilian Portuguese with Literary Context
Bonás, Giovana Kerche
Junior, Roseval Malaquias
Piau, Marcos
Laitz, Thiago
Almeida, Thales Sales
Abonizio, Hugo
Larcher, Celio
Pires, Ramon
Nogueira, Rodrigo
Computation and Language
We introduce CAPITU, a benchmark for evaluating instruction-following capabilities of Large Language Models (LLMs) in Brazilian Portuguese. Unlike existing benchmarks that focus on English or use generic prompts, CAPITU contextualizes all tasks within eight canonical works of Brazilian literature, combining verifiable instruction constraints with culturally-grounded content. The benchmark comprises 59 instruction types organized into seven categories, all designed to be automatically verifiable without requiring LLM judges or human evaluation. Instruction types include Portuguese-specific linguistic constraints (word termination patterns like -ando/-endo/-indo, -inho/-inha, -mente) and structural requirements. We evaluate 18 state-of-the-art models across single-turn and multi-turn settings. Our results show that frontier reasoning models achieve strong performance (GPT-5.2 with reasoning: 98.5% strict accuracy), while Portuguese-specialized models offer competitive cost-efficiency (Sabiazinho-4: 87.0% at \$0.13 vs Claude-Haiku-4.5: 73.5% at \$1.12). Multi-turn evaluation reveals significant variation in constraint persistence, with conversation-level accuracy ranging from 60% to 96% across models. We identify specific challenges in morphological constraints, exact counting, and constraint persistence degradation across turns. We release the complete benchmark, evaluation code, and baseline results to facilitate research on instruction-following in Portuguese.
title CAPITU: A Benchmark for Evaluating Instruction-Following in Brazilian Portuguese with Literary Context
topic Computation and Language
url https://arxiv.org/abs/2603.22576