Bring your own key means you supply the credentials for a service, here the key for an AI model provider, instead of using the vendor's. You choose the provider, pay it directly, and its terms apply to your requests.
For example, a data engineer on the Free plan would create a key in the console of the model provider they use, add it to Emolysis once, and from then on every request the agent makes, such as asking for a merge statement or explaining a failing test, would be billed to that provider account at the provider's own rates. The provider's limits, its data retention terms and its regional options apply, because the request is between you and the provider.
Bring your own key is common for developer tools that call AI models, because it lets teams use a provider they already have a contract with, keep spending in one place and apply their own security review. The trade-off is that you manage the key: you rotate it if it leaks, you watch the provider's usage and you set its spending limits. A key should never be committed to a repository or pasted into a shared file; a credential store on the machine keeps it out of project files.
With a paid plan, the alternative is included model usage, where requests pass through Emolysis's metering service to the provider and count against the plan. Either way, a prompt can include table and column names, schemas and sample values, so the choice of provider is also a choice about who sees that data. See coding agent and the security page.
Emolysis's Free plan is bring your own key: you add a key from the model provider you choose, the agent uses it, and Emolysis charges nothing for model usage. Every plan accepts your own key, and the key is kept in your machine's credential store. See Model keys and credits and Data handling.