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OneBucket runs two remote MCP servers: data, for objects, and events, for activity. Any MCP client that supports remote servers with OAuth can use them. This page covers what is the same for every client; the client pages cover only how to add the server.

Claude

Add OneBucket as a custom connector.

ChatGPT

Desktop app and web.

Muse

Connect from Muse chat.

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Endpoints

Regions today are us-ashburn-1, us-sanjose-1 and ap-singapore-1, for example https://data.us-ashburn-1.onebucket.io. The full list is in Endpoints.
Use the root URL exactly as shown. The MCP service is served at the root, so https://data.onebucket.io/mcp will not connect.
Global hostnames route each request to the nearest live region, and your policies are active in every region. Pin a region only when requests must land in one place. The two servers are separate connections: connecting data does not give access to events.

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Sign-in

Both servers use standard MCP authorization: OAuth 2.1 with PKCE. Clients discover the authorization server from the MCP endpoint (RFC 9728 and RFC 8414), so in most clients you only enter the URL.
  • No pre-registered app. Clients register themselves through Dynamic Client Registration as public clients, with no secret.
  • No pasted tokens. Never paste a token, secret or password into a chat or a connector dialog. Leave bearer-token and header fields empty.
  • Exact resource. The resource sent in the authorization, token and refresh requests must match the endpoint exactly. Tokens are bound to that one audience.
  • Scoped and revocable. Every call is scoped to your organization and access key. Revoke a session at any time from your OneBucket console or with onebucket sessions in the CLI. Disconnecting a client removes its access; it never deletes buckets or objects.

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Tools

Every data tool is governed by the policy of the bucket it touches. Read tools are annotated read-only, so clients can run them without asking; clients ask for confirmation before write tools.

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Reading

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Writing

delete and move are destructive: move removes the source object, and delete without a key deletes the bucket. Approve each write explicitly, and check the current state with a read before retrying a write that failed or timed out.

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Events

The events server is read-only. Each request produces one gateway event for the request as the client made it, plus one backend event for each endpoint it reached; all share one reqId, and backend events carry the endpoint. Filter or group by layer so one transfer is not counted twice. Only gateway events name the caller, so filtering by accessKey or user returns gateway events only.

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Limits

Above these limits, the tool returns a presigned URL so the transfer goes directly between the client and OneBucket, bypassing the model. copy, move, migrate and prefetch return once the job is queued, so a destination may not be readable for a short time.

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Verify a connection

Start with a read-only request, which proves the connection without changing data. Ask your assistant: “List my OneBucket buckets.” It should return the buckets your key can reach, with the backends that hold each one.