AI agents are becoming increasingly capable of discovering and using external APIs. But allowing an autonomous system to interact with paid services introduces an important challenge:

How can an AI agent use APIs without accidentally making duplicate payments?

This tutorial explores a safer approach using Koyori Utils API, a service offering 20,000 API operations for developers, bots, and AI agents.

The goal is to separate API discovery, payment authorization, and execution into clearly defined steps.

1. Discover APIs before attempting payment

A well-designed agent should inspect available tools before deciding whether to use a paid operation.

Koyori Utils API provides a public discovery catalog:

https://koyori-utils-api.koyori-aibtc.workers.dev/agents/catalog

For example:

curl -G \
  "https://koyori-utils-api.koyori-aibtc.workers.dev/agents/catalog" \
  --data-urlencode "q=json" \
  --data-urlencode "limit=3"

This request searches the public catalog. It does not initiate an STX payment.

Before calling any discovered operation, inspect the OpenAPI specification:

https://koyori-utils-api.koyori-aibtc.workers.dev/openapi.json

This helps an AI agent determine the correct HTTP method, request format, and applicable requirements.

2. Separate discovery from purchasing

Finding an API does not mean an AI agent should purchase access automatically.

A safer workflow follows these steps:

1. Discover a relevant API.
2. Inspect its request and response schemas.
3. Check the current pricing and access requirements.
4. Request explicit human authorization before purchasing.
5. Execute the approved operation only after access has been confirmed.

Current subscription information is available here:

https://koyori-utils-api.koyori-aibtc.workers.dev/subscription

An agent should never assume that an old example or cached price is still correct.

3. Handle pending blockchain payments safely

Blockchain transactions may not be reflected immediately in every service.

A particularly dangerous automation pattern is:

Payment appears unsuccessful → Agent automatically pays again

This can result in duplicate charges.

Instead, design the agent to record:

• The purchase or order identifier
• The blockchain transaction ID, when available
• The payment submission time
• The latest observed payment status

If the payment is still pending or its status is uncertain, the agent should perform a non-paying status check later.

Never automatically send a second payment simply because the first confirmation is delayed.

A temporary error, pending status, or missing receipt should not be treated as definitive proof that funds were not transferred.

4. Protect API keys and wallet credentials

Payment safety also means protecting sensitive information.

AI agents should never expose:

• Wallet seed phrases or private keys
• Account passwords
• Full subscription API keys
• Authentication tokens

Store credentials securely and provide the agent with only the access required for its task.

Avoid putting secrets into public repositories, debug logs, or AI prompts.

5. Follow a documented activation workflow

Koyori Utils API offers a dedicated guide for AI agents:

https://koyori-utils-api.koyori-aibtc.workers.dev/agents/quickstart

The guide covers discovery, purchasing considerations, and getting started.

For a practical read-only discovery example, see the project's GitHub documentation:

https://github.com/sophiaalice0913-cmyk/koyori-utils-api/blob/main/docs/AI_AGENT_DISCOVERY_EXAMPLE.md

Conclusion

An AI agent that uses paid APIs should be designed around four principles:

Discover first. Understand the available operations before making calls.

Authorize explicitly. Require human approval for purchases and wallet signatures.

Never assume payment failure. Investigate pending transactions without automatically paying twice.

Protect credentials. Keep API keys and wallet secrets outside public outputs.

These principles help make API-powered automation safer and more predictable.

Explore Koyori Utils API:

https://koyori-utils-api.koyori-aibtc.workers.dev/

Disclosure: This article introduces a project I am involved with and was prepared with AI writing assistance.