The Credentials panel before anything has been requested. It fills itself during a build.
You Are Asked, You Do Not Go Looking
Credentials arrive by request. When the agent writes code that needs a third-party key, it stops and asks you for it. The panel starts empty and fills as that happens, which is what its empty state says: credentials appear here when the agent requests them during development. You can decline. If you skip a credential, the agent proceeds without it and is instructed not to ask again for the same one.Two Kinds of Secret
The agent never asks you for something it can generate. Internal values are created for you with no involvement, so the only things you are asked for are keys that come from outside.
The Agent Cannot Read Your Secrets
This is the part worth understanding, because it changes how much you need to worry about pasting a key in. Values are masked before the agent sees them. When the agent reads a.env file, credential values are replaced with a placeholder. It can see that a credential is set and refer to it by name, but the value itself never reaches it.
The agent can also ask which credentials exist without seeing any of them, which is how it checks whether it needs to request something before asking you again.
It can write stored values back into your application’s configuration when the application needs them. That happens without the value passing through the conversation.
The agent is instructed never to write the masking placeholder into a file, and never to search for it. Both would break the application, because the file on disk holds the real value.
Where They End Up
Credentials are stored against the project and written into the root configuration file the application reads at runtime. Every credential, constant, port, and host lives in that one file, which the application reads when it starts.Your Next Step
Credentials are one of the things the agent handles on your behalf. The full set is worth knowing.See what else the agent does unasked
Its capabilities, its rules, and the boundaries around them.
Connect an external tool instead
Giving the agent access to a service through MCP.