The Role of Agentic Instruction Categories for Code Generation: A Study of Five Python Libraries

Warren Gerald Polandra, Yoshiki Higo, Raula Gaikovina Kula

Agentic coding systems increasingly rely on repository-level agent files, such as AGENTS.md, to communicate project knowledge and developer intent. However, it remains unclear which categories of agent instructions enable efficient agent-file generation and accurate code generation. We evaluate five instruction categories: Repository Overview, Function Description, Implementation Detail, Testing, and Reconstruction Steps, across all 31 non-empty combinations using two Large Language Models (LLMs), Gemma 4 and GPT-5.4, and five human-written Python libraries. Our study addresses two research questions, comprising five sub-questions, on agent file generation and code generation. Results show that the number of instructions alone does not determine token usage for agent-file generation, with substantial variation across models and libraries. Although most AI-generated libraries compiled successfully regardless of the instruction combination, functional correctness remained limited. No Gemma 4 variant passed all tests, whereas 12.99% of GPT-5.4 variants did. Function Description achieved Gemma 4's highest partial-pass rate, while Reconstruction Steps achieved GPT-5.4's highest…