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Set up the Cloud Storage MCP server

Google's Cloud Storage MCP server lets AI agents work with buckets and objects in Google Cloud Storage: list buckets and objects, read object metadata and contents, write text objects, and create or delete buckets and objects. This guide walks through enabling the Cloud Storage API, granting IAM roles to users, creating an OAuth client in Google Cloud, and connecting the server to MintMCP.

Prerequisites​

  • A MintMCP admin account
  • A Google Cloud project with billing enabled and at least one Cloud Storage bucket

Enable the Cloud Storage API​

  1. Go to console.cloud.google.com/apis/enableflow?apiid=storage.googleapis.com and select your project.
  2. On Confirm project, check that the correct project is selected and click Next.
  3. On Enable API, click Enable. Enabling the Cloud Storage API also enables its MCP server.

Grant IAM roles​

Each user who connects to Cloud Storage through MintMCP needs IAM roles on the Google Cloud project or on individual buckets.

  1. Go to console.cloud.google.com/iam-admin/iam and select your project.
  2. To add roles to a user already listed, click the edit (pencil) icon on their row. To add a new user, click Grant access and enter their email address or a Google Group.
  3. Add the roles, clicking + Add another role for each:
    • MCP Tool User (roles/mcp.toolUser) to make MCP tool calls
    • Storage Object Viewer (roles/storage.objectViewer) to list objects and read object data and metadata
    • Storage Object Creator (roles/storage.objectCreator), only for users who should write objects
    • Storage Object User (roles/storage.objectUser), only for users who should delete objects
    • Storage Admin (roles/storage.admin), only for users who should create, list, or delete buckets
  4. Click Save.

For narrower access, grant the storage roles on individual buckets rather than the whole project. roles/mcp.toolUser must be granted at the project level.

Create an OAuth client​

The OAuth client gives MintMCP a Client ID and secret to broker each user's Google sign-in. Create one Web application client and point its redirect URI at MintMCP's callback.

  1. Go to console.cloud.google.com/auth/clients and select your project.

  2. If prompted to configure the OAuth consent screen, set the user type to Internal (Google Workspace organizations only). This restricts access to users in your org and skips Google app verification, which is otherwise required for the Cloud Storage scopes.

  3. Click Create client.

  4. Set Application type to Web application and give it a name (for example, MintMCP OAuth).

    Create OAuth client ID form with application type set to Web application and a name field

  5. Under Authorized redirect URIs, click Add URI and enter:

    https://app.mintmcp.com/oauth/callback

    Leave Authorized JavaScript origins empty. This URI must match the Redirect URL in the connector's OAuth settings exactly, or sign-in fails with redirect_uri_mismatch.

    Authorized redirect URIs field set to the MintMCP OAuth callback URL

  6. Click Create. Google shows the Client ID and Client secret once, so copy both now: you can't view the secret again after closing the dialog.

Reopen the client anytime from the Clients list to edit its redirect URIs or rotate the secret.

Add Cloud Storage to MintMCP​

  1. In MintMCP, go to MCP store → Manage store.
  2. Find Google Cloud Storage in the recommended servers list and click Install.
  3. Open the connector's OAuth settings and enter the Client ID and Client secret from the OAuth client you created.
  4. Confirm the Redirect URL shown in the connector's OAuth settings matches the URI you added to the OAuth client (https://app.mintmcp.com/oauth/callback). They must be identical, or sign-in fails with redirect_uri_mismatch.
  5. Click Save.

Security considerations​

  • Access is controlled by Google Cloud IAM: users without the required roles receive an authorization error when they call a tool. API keys are not supported.
  • Each user authenticates individually with their own Google account, so all operations run under their identity and appear in Cloud Audit Logs.
  • Destructive tools (delete_bucket, delete_object, write_text) ship in the default toolset. Restrict them with tool customization in MintMCP, or with IAM deny policies, see Control MCP use with IAM.
  • Admin Activity audit logs are on by default. Enable Data Access audit logs on the Cloud Storage API to also capture read operations.

Next steps​