How to buy an AI agent (what to check first)

Buying an AI agent is not like buying software you install — you are buying a

tested recipe for getting a model to complete a job autonomously. The trick

is knowing what to check before you pay. Here is a buyer's checklist.

What to check before you buy an AI agent

1. A tested runbook. The best signal an agent works is a visible, tested

sequence of steps and tool calls. If you cannot see what it does, treat that

as a question, not a leap of faith.

1. The model it was tested on. Performance varies by model. A good listing

names the model the creator tested the agent on.

1. The token cost per run. Agents run multiple steps, so they use more

tokens than a single prompt. Check the estimate so there are no billing

surprises — the [how we count tokens](/learn/how-we-count-tokens) guide

explains what to look for.

1. Scope and guardrails. A narrow agent that does one job well beats a vague

"does everything" agent. Look for clear limits.

1. Reviews and sales. Social proof from other buyers is the fastest way to

judge reliability.

1. Editability. On Sigrix you own an editable copy, so you can adapt the

goal and guardrails to your workflow — confirm you can change what you need.

How to buy an AI agent, step by step

1. Browse the [AI agent marketplace](/marketplace/agents) and shortlist

agents that match your job.

1. Compare the runbook, model, token cost, and reviews across your

shortlist.

1. Buy and claim your editable copy.
2. Run it on your model, then adapt the goal and guardrails to your own

inputs.

Not sure an agent is the right building block? An assistant works with you

turn by turn, while an agent works for you autonomously — the

[building blocks guide](/learn/ai-building-blocks) draws the line.

FAQ

How do I buy an AI agent?

Browse a marketplace like Sigrix, compare agents by their tested runbook, model,

token cost, and reviews, then buy an editable copy you own and run it on your

model. [Start browsing](/marketplace/agents).

What should I look for when buying an AI agent?

A visible tested runbook, the model it was tested on, the token cost per run,

clear scope, reviews, and the ability to edit it after you buy.

How much does an AI agent cost?

It varies by listing — some are free to claim, others are paid. Separately, the

running cost is the model tokens the agent uses, which each listing estimates.

Are marketplace AI agents safe to use?

Favor agents with a visible runbook, clear guardrails, and reviews. Because you

get an editable copy on Sigrix, you can inspect and adjust what the agent does

before relying on it.

Is buying an AI agent better than building one?

If a tested agent already does your job, buying skips the prompt engineering,

tool wiring, and edge-case testing — and you can still adapt it. Build only when

nothing on the [marketplace](/marketplace/agents) fits.

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Ready to compare? [Browse the AI agent marketplace](/marketplace/agents).