$\texttt{YC-Bench}$: Benchmarking AI Agents for Long-Term Planning and Consistent Execution

Fuente: arXiv
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Main Authors: He, Muyu, Jain, Adit, Kumar, Anand, Tu, Vincent, Bakshi, Soumyadeep, Patro, Sachin, Rajani, Nazneen
Format: Preprint
Published: 2026
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author He, Muyu
Jain, Adit
Kumar, Anand
Tu, Vincent
Bakshi, Soumyadeep
Patro, Sachin
Rajani, Nazneen
author_facet He, Muyu
Jain, Adit
Kumar, Anand
Tu, Vincent
Bakshi, Soumyadeep
Patro, Sachin
Rajani, Nazneen
contents As LLM agents tackle increasingly complex tasks, a critical question is whether they can maintain strategic coherence over long horizons: planning under uncertainty, learning from delayed feedback, and adapting when early mistakes compound. We introduce $\texttt{YC-Bench}$, a benchmark that evaluates these capabilities by tasking an agent with running a simulated startup over a one-year horizon spanning hundreds of turns. The agent must manage employees, select task contracts, and maintain profitability in a partially observable environment where adversarial clients and growing payroll create compounding consequences for poor decisions. We evaluate 12 models, both proprietary and open source, across 3 seeds each. Only three models consistently surpass the starting capital of \$200K, with Claude Opus 4.6 achieving the highest average final funds at \$1.27 M, followed by GLM-5 at \$1.21 M at 11$\times$ lower inference cost. Scratchpad usage, the sole mechanism for persisting information across context truncation, is the strongest predictor of success, and adversarial client detection is the primary failure mode, accounting for $47\%$ of bankruptcies. Our analysis reveals that frontier models still fail through distinct failure modes such as over-parallelization, demonstrating the capability gaps for long-horizon performance. $\texttt{YC-Bench}$ is open-source, reproducible, and configurable.
format Preprint
id arxiv_https___arxiv_org_abs_2604_01212
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle $\texttt{YC-Bench}$: Benchmarking AI Agents for Long-Term Planning and Consistent Execution
He, Muyu
Jain, Adit
Kumar, Anand
Tu, Vincent
Bakshi, Soumyadeep
Patro, Sachin
Rajani, Nazneen
Computation and Language
Artificial Intelligence
As LLM agents tackle increasingly complex tasks, a critical question is whether they can maintain strategic coherence over long horizons: planning under uncertainty, learning from delayed feedback, and adapting when early mistakes compound. We introduce $\texttt{YC-Bench}$, a benchmark that evaluates these capabilities by tasking an agent with running a simulated startup over a one-year horizon spanning hundreds of turns. The agent must manage employees, select task contracts, and maintain profitability in a partially observable environment where adversarial clients and growing payroll create compounding consequences for poor decisions. We evaluate 12 models, both proprietary and open source, across 3 seeds each. Only three models consistently surpass the starting capital of \$200K, with Claude Opus 4.6 achieving the highest average final funds at \$1.27 M, followed by GLM-5 at \$1.21 M at 11$\times$ lower inference cost. Scratchpad usage, the sole mechanism for persisting information across context truncation, is the strongest predictor of success, and adversarial client detection is the primary failure mode, accounting for $47\%$ of bankruptcies. Our analysis reveals that frontier models still fail through distinct failure modes such as over-parallelization, demonstrating the capability gaps for long-horizon performance. $\texttt{YC-Bench}$ is open-source, reproducible, and configurable.
title $\texttt{YC-Bench}$: Benchmarking AI Agents for Long-Term Planning and Consistent Execution
topic Computation and Language
Artificial Intelligence
url https://arxiv.org/abs/2604.01212