AI Agent Spec Builder

Build a clear specification for an AI agent covering its goals, tools, guardrails and behavior before you build it, free in your browser.

100% FreeRuns in your browserIntermediate

How to use this calculator

Agent spec

Goal — what should the agent do?Tools / APIs available (one per line)Constraints (one per line)Success criteria

Your prompt

Copy-ready prompt

Write a planning spec for an AI agent (a plan, not code).
Goal: [what should the agent achieve?]
Deliver: the agent's role, a step-by-step plan, which tool to use at each step, guardrails and failure handling, and how to verify success. Keep it deterministic and safe; ask for missing info rather than assuming.

~75 tokens53 words311 chars

A template built from your inputs — paste it into your AI tool. Runs in your browser; nothing is uploaded.

How to use this calculator

State the agent's goal and list the tools/APIs it can use.
Add constraints and success criteria.
Copy the prompt to generate the agent's planning spec.

How it works

The prompt asks for a deterministic, safe plan — the agent's role, a step-by-step sequence with the tool used at each step, guardrails and failure handling, and how to verify success — and to ask for missing info rather than assume.

It builds the planning prompt; it does not run an agent or write code.

Common mistakes

Leaving the agent's tools and limits undefined — vague specs lead to unpredictable behaviour.
Omitting guardrails; always state what the agent must not do.

Frequently asked questions

Does this use AI or send my prompt anywhere?

No. It runs entirely in your browser using rule-based checks — your prompt is never uploaded or sent to any AI model. Still, avoid pasting passwords, API keys or private data into any tool.

What is an agent spec?

A clear description of an AI agent's goal, tools, inputs, outputs and guardrails. The tool assembles your choices into a spec prompt or document.

Does it build the agent?

No — it produces the specification you'd hand to a developer or paste into an agent framework; nothing is run or uploaded here.

Related tools

Explore more in AI Tools.

Cite this tool

Zerdly. (2026). AI Agent Spec Builder. Retrieved from https://www.zerdly.com/tools/ai-agent-spec-builder/

Tip: Enter any known values to calculate the remaining results.

All calculations run in your browser. Your inputs are never saved or transmitted.