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State-Of-The-Art Prompting For AI Agents

May 30, 2025· 31 min· 343K views·Watch on YouTube

Speakers

Y Combinator’s Jared, Diana, and Harj discuss prompt engineering, evaluation, and founder-led customer work on The Lightcone podcast.

How Parahelp structures an agent prompt

Jared shares a six-page prompt from Parahelp, whose AI handles customer support for companies including Perplexity, Replit, and Bolt. Diana describes its role definition, step-by-step plan, tool-call rules, and structured output. The prompt sets company-wide behavior, while customer-specific workflows and examples go into a developer prompt.

Improve prompts with examples and escape hatches

The hosts describe metaprompting: using a model to revise prompts based on failures, or to create a specialized prompt for a query. For difficult tasks, Jasberry adds expert examples of bugs such as N+1 queries to guide the model. They also recommend letting agents report when information is missing or instructions are unclear, so developers can fix the workflow instead of receiving a guess.

Evals capture what customers value

The hosts argue that evaluation data is more valuable than a prompt alone because it explains why the prompt was designed as it was and how to improve it. They recommend learning a customer’s workflow firsthand, then turning those observations into specific tests, such as whether to honor a tractor warranty after an invoice arrives. Understanding those details can give a startup an advantage.

Founders work directly with customers

Drawing on Palantir’s forward-deployed engineering model, Jared describes engineers observing customers’ work and building software around real processes. He says founders should do this themselves: listen, build a tailored demo, gather feedback, and return with a working solution. The hosts point to AI startups including Giga ML and HappyRobot as examples of teams using rapid iteration and customer-specific demos to win large deals.

Models respond differently to rubrics

The hosts say models can have different working styles and suit different tasks. Harj reports that, in their scoring example, o3 followed a rubric rigidly, while Gemini 2.5 Pro was more willing to reason about exceptions. They compare prompt work to both programming and managing a person: make expectations and evaluation criteria clear, then improve the process using feedback.

Takeaways

  • Structure agent prompts with clear roles, steps, constraints, and output formats.
  • Use failed examples to refine prompts, especially when a task is difficult to specify precisely.
  • Give agents a way to flag missing information or confusing instructions.
  • Build evaluations from direct observation of the customer’s workflow and priorities.
  • Founders can win trust by returning quickly with a tailored, working demo.

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What was claimed 11

  • integrates with
    Parahelp integrates with Perplexity
    “They’re powering customer support for Perplexity”
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    Unverified1 source· Talk
  • feature
    Parahelp: AI customer support
    “Parahelp does AI customer support.”
    YouTube
    Unverified1 source· Talk
  • feature
    Parahelp: Agent prompt is six pages long
    “it’s six pages long as we scroll through it”
    YouTube
    Unverified1 source· Talk
  • feature
    Tropy: Prompt folding
    “they’ve figured out is prompt folding”
    YouTube
    Unverified1 source· Talk
  • feature
    Tropy: Prompt and return-value debugging for multistage workflows
    “in-depth understanding and debugging of prompts and return values from a multistage workflow”
    YouTube
    Unverified1 source· Talk
  • feature
    Jasberry: Automatic bug finding in code
    “They build automatic bug finding in code”
    YouTube
    Unverified1 source· Talk
  • feature
    Gemini 2.5 Pro: Long context window and reasoning traces that can help diagnose prompt misses
    “you can learn a lot about misses by looking at the thinking traces”
    YouTube
    Unverified1 source· Talk
  • feature
    Palantir: Institutionalized and scaled forward-deployed engineering
    “Palantir was probably the first company to institutionalize that and scale it as a process”
    YouTube
    Unverified1 source· Talk
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