AI tools are becoming part of everyday work for developers, analysts and small businesses. Many of these tools do not run their own AI models. Instead, they connect to providers such as OpenAI, Anthropic or Google using an API key, a long secret string that lets software use the provider’s service and bills the key owner for every request. A security incident disclosed over the weekend shows how valuable, and how exposed, those keys can be.

What happened at OpenCode

OpenCode is an open-source AI coding agent that helps people understand code, write features and fix bugs using plain-language instructions. It runs in a terminal, a desktop app or a code editor, and users can link their own accounts with several AI providers through a web dashboard called the OpenCode Console.

On Saturday, 17 October 2026, the project disclosed what it described as a large-scale “distillation attack”. According to reporting by BleepingComputer, the incident affected about 1.4% of OpenCode Console users, specifically those who had linked external AI providers. The API keys those users had stored were exposed. OpenCode said the earliest possible exposure was 00:30 UTC on 17 October and that it had seen no evidence of other data being taken.

The consequences were immediate for some people. Users reported unauthorised charges on their AI accounts ranging from several hundred dollars to more than $1,700 overnight, and some said Google had suspended their cloud projects for activity consistent with hijacked resources. OpenCode emailed affected users, said those without an email were not affected, mentioned possible reimbursement, and said it was working with the AI providers involved.

What is a distillation attack?

Distillation itself is a legitimate machine-learning technique: a smaller model is trained on the answers produced by a larger, more capable model. It becomes an attack when someone runs that process at huge scale without permission, often using other people’s accounts so the cost and the rule-breaking land on someone else. Stolen API keys are ideal for this, because each one comes with a paid account and its own usage limits. OpenCode’s co-founder said attackers had been probing the company’s systems for at least 48 hours, using AI agents of their own.

Why AI API keys are a growing target

An AI API key is essentially a prepaid or post-paid credit line. Unlike a stolen password, it often does not need a second factor to use, and it may keep working until someone notices the bill. There are three reasons the risk is rising:

• More places hold keys. Coding agents, browser extensions, automation tools and no-code platforms all ask you to paste a key in.
• Usage is easy to monetise. Criminals can resell access, use it for distillation, or run spam and scam content at your expense.
• Costs scale fast. Automated misuse can run thousands of requests an hour, so a bill can grow overnight, as OpenCode users found.

None of this means AI tools are unsafe to use. It means an API key deserves the same care as a bank card.

How to protect your AI API keys

1. Use one key per tool. Create a separate key for each app or service. If one is exposed, you can revoke it without breaking everything else, and you can see which tool leaked.
2. Set spending limits and alerts. Most AI provider dashboards let you set monthly budgets, usage alerts or caps. Set them low and raise them when needed.
3. Limit permissions. Where the provider allows it, restrict keys to specific models, projects or features, and use separate projects for testing and production.
4. Never put keys in code or chats. Keep them out of source code, shared documents, screenshots and messaging groups. Use environment variables or a secrets manager, and add key files to your .gitignore.
5. Rotate keys regularly, and immediately after any breach notice from a tool you use.
6. Remove keys you no longer use. Old keys sitting in forgotten tools are easy pickings.
7. Protect the provider account itself with multi-factor authentication, since anyone in the account can create new keys.
8. Check billing weekly during the first months of using any new AI tool.

What to do if you used OpenCode

• Check your inbox for a notification from OpenCode. The company says users who did not receive one were not affected.
• If you linked AI providers to the OpenCode Console, revoke those keys in each provider’s dashboard and create new ones as a precaution.
• Review your AI and cloud billing for charges since 17 October and contact the provider about anything unexpected.
• If a cloud project was suspended, follow the provider’s appeal process and explain the breach.

The lesson is broader than one tool. As AI services become everyday business utilities, the keys that unlock them become targets, and simple habits such as separate keys, spending caps and regular rotation can turn a potentially expensive incident into a minor inconvenience.

Sources

• BleepingComputer: OpenCode hack exposes API keys amid AI distillation attacks