WhoBuilt

The Powerful Alternative To Fine-Tuning

Feb 27, 2026· 20 min· 58K views·Watch on YouTube

Speaker

Ian Fisher, co-founder and co-CEO of Poetic, discusses the company’s AI reasoning harnesses with the host of Y Combinator’s The Light Cone.

Building on top of new models

Fisher says Poetic aims to improve how language models solve hard problems without training new models from scratch. Its harnesses combine models with code, prompts, and data, and can be adapted as newer models become available. He argues this can avoid the cost and obsolescence risks of fine-tuning.

Benchmark results and costs

Fisher describes Poetic’s results on ARC-AGI-2: 54% verified performance at $32 per problem, compared with Gemini 3 Deep Think at 45% and about $70 per problem. He also says Poetic reached 55% on Humanity’s Last Exam, above the cited 53.1% result from Claude Opus 4.6. The optimization for that run cost less than $100,000, and the company had seven research scientists and engineers.

How the meta-system improves agents

Fisher says Poetic’s meta-system automatically generates or optimizes systems for difficult tasks. Customers can bring an existing agent for optimization of prompts, reasoning strategies, or other parts. He says improvements can come from reasoning strategies written in code: in an earlier DeepMind project, adding these strategies raised performance with Gemini 1.5 Flash from about 5% to 95% on the hardest task.

Letting AI inspect the data

Fisher says Poetic’s system examines task data and decides whether it needs more context, generated examples, or other changes. For one benchmark, it produced prompts that Fisher says a person would not typically write, including a simple example that appeared incorrect; the team left the output unchanged. He describes this as shifting dataset analysis and failure-mode discovery to the AI system.

Getting started and career advice

Poetic had not yet released its product at the time of the conversation, but Fisher invited companies with difficult reliability problems to sign up for early access at poetic.ai. He also recounts moving from a mobile tools startup and computer security into machine learning research at Google and DeepMind. His advice to engineers is to use AI regularly, test its limits, and try building things they want to make.

Takeaways

  • A model-agnostic harness may let a product benefit from new foundation models without repeating a costly fine-tuning cycle.
  • Measure both task performance and inference cost when comparing an agent with a base model.
  • For hard tasks, coded reasoning strategies may improve performance beyond prompt optimization alone.
  • Test AI systems on your own task data and inspect where they fail before deciding what to optimize.
  • Build with AI regularly to learn its current capabilities and limits firsthand.

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