Agent setup

Agent Setup tells Tuner what your agent is and what it’s supposed to do. Tuner uses these settings to score calls, generate simulation Scenarios and diagnose failures, so they matter well beyond the agent’s name.

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What each setting is used for

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Why the prompt and workflow matter

Tuner judges and tests your agent against the prompt and workflow saved here, not the ones running on your platform.

• Evals: a custom eval can read the system prompt and workflow when you add them under Inputs Used, so the judge scores the call against your actual instructions.
• Simulation: generated Scenarios are written from your prompt and workflow, so the Simulated Callers test what your agent is meant to handle.
• Diagnosis: MCP diagnosis compares failing calls against them to find the root cause.

If they’re out of date, evals score against old rules, simulations test old behavior, and diagnosis blames the wrong instructions. If they’re empty, all three have nothing to compare against.

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Keep them current

Update this tab every time you change your agent’s prompt or workflow in production. Retell and Vapi agents: when you pick a Retell or Vapi agent in the wizard, Tuner copies its system prompt from the provider once. It doesn’t pull later changes, and saving here doesn’t change the prompt on Retell or Vapi. When you edit the prompt on your provider, paste the new version here too. To edit, open Agent Settings > Agent Setup, change the fields and click Save Changes. To update these settings from code, use Update Agent.

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Next steps