# Do programming languages still matter to your AI coding agent teammate? Evidence at scale from chess engines

arXiv: https://arxiv.org/abs/2606.13763 · HTML: https://mlsanity.com/paper/2606.13763/

## Key facts

- Cited by 1 papers in the map (data through 14 Oct 2026).
- Placed in Software engineering coding agents, one of 16 directions in LLM agents and tool use.
- Builds on 20 of its 47 references that are in the map.
- First posted on arXiv 11 Jun 2026.

## Placed in

- LLM agents and tool use / [Software engineering coding agents](https://mlsanity.com/agents/software-engineering-coding-agents/)

## Builds on (most cited first, 20 of 20)

- [Evaluating Large Language Models Trained on Code](https://mlsanity.com/paper/2107.03374/) (2021)
- [Program Synthesis with Large Language Models](https://mlsanity.com/paper/2108.07732/) (2021)
- [LiveCodeBench: Holistic and Contamination Free Evaluation of Large Language Models for Code](https://mlsanity.com/paper/2403.07974/) (2024)
- [Mastering Chess and Shogi by Self-Play with a General Reinforcement Learning Algorithm](https://mlsanity.com/paper/1712.01815/) (2017)
- [StarCoder 2 and The Stack v2: The Next Generation](https://mlsanity.com/paper/2402.19173/) (2024)
- [Agentless: Demystifying LLM-based Software Engineering Agents](https://mlsanity.com/paper/2407.01489/) (2024)
- [RepoCoder: Repository-Level Code Completion Through Iterative Retrieval and Generation](https://mlsanity.com/paper/2303.12570/) (2023)
- [Multi-SWE-bench: A Multilingual Benchmark for Issue Resolving](https://mlsanity.com/paper/2504.02605/) (2025)
- [Measuring AI Ability to Complete Long Software Tasks](https://mlsanity.com/paper/2503.14499/) (2025)
- [SWE-rebench: An Automated Pipeline for Task Collection and Decontaminated Evaluation of Software Engineering Agents](https://mlsanity.com/paper/2505.20411/) (2025)
- [SWE-PolyBench: A multi-language benchmark for repository level evaluation of coding agents](https://mlsanity.com/paper/2504.08703/) (2025)
- [DevEval: A Manually-Annotated Code Generation Benchmark Aligned with Real-World Code Repositories](https://mlsanity.com/paper/2405.19856/) (2024)
- [ProgramBench: Can Language Models Rebuild Programs From Scratch?](https://mlsanity.com/paper/2605.03546/) (2026)
- [Commit0: Library Generation from Scratch](https://mlsanity.com/paper/2412.01769/) (2024)
- [Prompting Large Language Models to Tackle the Full Software Development Lifecycle: A Case Study](https://mlsanity.com/paper/2403.08604/) (2024)
- [Guidelines for Empirical Studies in Software Engineering involving Large Language Models](https://mlsanity.com/paper/2508.15503/) (2025)
- [Unified Software Engineering Agent as AI Software Engineer](https://mlsanity.com/paper/2506.14683/) (2025)
- [The Rise of AI Teammates in Software Engineering (SE) 3.0: How Autonomous Coding Agents Are Reshaping Software Engineering](https://mlsanity.com/paper/2507.15003/) (2025)
- [Stalled, Biased, and Confused: Uncovering Reasoning Failures in LLMs for Cloud-Based Root Cause Analysis](https://mlsanity.com/paper/2601.22208/) (2026)
- [Benchmarking AI Models in Software Engineering: A Review, Search Tool, and Unified Approach for Elevating Benchmark Quality](https://mlsanity.com/paper/2503.05860/) (2025)

## Built on by (most cited first, 1 of 1)

- [Compiled Agency: Frontier General-Purpose Coding Agents Build Winning Game Players from Bare Interaction - from Flappy Bird to StarCraft II and Civilization](https://mlsanity.com/paper/2609.18996/) (2026)

## Abstract (arXiv)

Frontier coding agents now promise end-to-end authorship of complete software systems. Two empirical questions follow: can AI coding-agent teammates program in any target language, including ones with no comparable prior open-source artefact? If so, does language choice still shape the artefact, and along which dimensions? We study both through a polyglot case study built around chess engines: non-trivial multi-component systems that admit a hierarchy of language-agnostic oracles, from exact move-generation correctness to a strength scale (Elo), observable from Rust to Brainfuck. We prompted two frontier agents (Claude Code and Codex) at the capability level, without chess knowledge or implementation guidance, under a documented intervention and stopping policy. The agents produced 34 chess engines spanning 17 primary programming languages, from mainstream to specialised, domain-specific, legacy, and esoteric targets. We combine per-engine feature analysis, independent Elo assessment, and session trajectories with qualitative analysis of code and transcripts. Frontier coding agents are genuinely polyglot: every language we tried produced at least one feature-rich working engine, several with no prior open-source counterpart of comparable scope (e.g., LaTeX), and the code is synthesised from scratch rather than copied. Yet language choice still matters: strong playing strength is only reachable in mainstream compiled languages, cost and engineering effort grow sharply as the language becomes more exotic, and feature choices shift across language families. Agents validate their own work unprompted, but their strength self-estimates are biased and a few engines cheated by calling a chess library. Programming language is no longer about whether AI teammates can build a working system, but about performance, cost, what gets built, and how much human supervision validation still needs.