Neural nets for agents: hardcoding is cheaper than reasoning models

The closed PAC1 benchmark, in which an AI agent must read logs, find files and sidestep prompt injections, unexpectedly exposed a weakness of reasoning models. According to the author, they hallucinated, broke JSON and burned through their API budget by looping on errors. In the end, the task was handled better by Zero-Cost Agent, a deterministic hardcoded executor that simulates a neural network's behavior but runs more stably and cheaply in a formal sandbox.

AI-processed from Habr AI; edited by Hamidun News
Neural nets for agents: hardcoding is cheaper than reasoning models
Source: Habr AI. Collage: Hamidun News.
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The closed PAC1 benchmark for AI agents showed that expensive reasoning models are not always better: a hackathon participant built Zero-Cost Agent from simple algorithms, which beat them on cost and completed the tasks more efficiently.

Why did a simple algorithm beat an AI model on cost?

Rigid algorithms avoid the typical mistakes neural networks make on structured tasks, such as working with logs, files and emails. Neural networks are vulnerable to Indirect Prompt Injections, where a malicious instruction is hidden inside the data. Against such traps, rigid rules work more reliably and cheaply.

Why is hardcoding cheaper than neural networks?

Because it does not require API calls to expensive reasoning models and uses rigid algorithms to perform tasks such as reading logs, finding files and sending emails.

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Key Questions Answered

Why did a simple algorithm beat an AI model on cost?

Rigid algorithms avoid the typical mistakes neural networks make on structured tasks, such as working with logs, files and emails. Neural networks are vulnerable to Indirect Prompt Injections, where a malicious instruction is hidden inside the data. Against such traps, rigid rules work more reliably and cheaply.

Why is hardcoding cheaper than neural networks?

Because it does not require API calls to expensive reasoning models and uses rigid algorithms to perform tasks such as reading logs, finding files and sending emails.

ZK
Zhemal Khamidun — CPO at Alpina Digital, product manager of AlpinaGPT. Building AI products since 2019. Hamidun News is a pet project that grew into a production aggregator with 6,000+ readers.
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