> ## Documentation Index
> Fetch the complete documentation index at: https://docs.onebucket.io/llms.txt
> Use this file to discover all available pages before exploring further.

# Agents reach data through MCP

> Agents and RAG over data in several stores, inside limits you set

## The situation

The business wants agents and RAG over documents and datasets spread across stores. Security will not hand an agent raw cloud keys, and nobody wants to copy everything into one place first.

## What OneBucket changes

The data plane speaks MCP natively, with OAuth 2.1 and audience-bound tokens. A policy sets the outer limits per key; inside them the agent lists, reads and writes at runtime. Every call is logged, and a key can be dropped to read-only instantly.

![An agent or RAG pipeline calls the OneBucket MCP server with OAuth 2.1, under a per-key policy, reaching contracts on Azure Blob, reports on AWS S3 and an archive on-prem](https://mintcdn.com/onebucket/IRmZGtHTOOl3yo0n/images/scenarios/agents.png?fit=max\&auto=format\&n=IRmZGtHTOOl3yo0n\&q=85\&s=da7c3477f6b64619e3ac8ff9b5d56617)

## How it works

* **No cloud keys on the agent.** The agent authenticates to OneBucket with OAuth 2.1 (PKCE), gets a token bound to one audience, and operates under the policy attached to its key. Backend credentials never leave the secure vault.
* **Tools.** `list`, `head`, `get`, `put`, `copy`, `move`, `migrate`, `locate`, `prefetch` and `presign` over the Core MCP. Large objects are handed back as presigned URLs so they bypass the model.
* **Kill switch.** Reassign a key from a read/write policy to a read-only policy and the next write fails, with the attempt visible on the event stream.
* **Audit.** Every operation is an event, scoped to organization and key, listed and tailed over the Events MCP.
* **Nothing to install.** OneBucket ships as an MCP connector in Claude and works with any MCP client.

## Related

* [Claude connector](https://docs.onebucket.io/connectors/claude.md)
* [How authentication works](https://docs.onebucket.io/connectors/claude.md#how-authentication-works): OAuth 2.1, audience binding
* [Fewer tokens: know before fetching](https://docs.onebucket.io/scenarios/token-economics.md)


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