browser_upload_file | PolicyLayer

WHAT IT DOES

What browser_upload_file does on Amazon Bedrock Knowledge Base Retrieval MCP Server

AI agents use browser_upload_file to create or update resources in Amazon Bedrock Knowledge Base Retrieval MCP Server — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Amazon Bedrock Knowledge Base Retrieval MCP Server environment.

THE RISK

Medium Risk

Why browser_upload_file needs a policy

File uploads are write operations that create or store data. Without documentation, the scope of what can be uploaded and where is unclear, creating moderate risk if an agent uploads malicious or sensitive content. Classified as Write rather than Execute because the tool itself does not execute code—it transfers files—though downstream processing could be concerning. Confidence is moderated due to empty description.

From the tool's definition Tool name 'browser_upload_file' indicates file upload capability. Description is empty, limiting direct evidence of intended behavior.

Documented attack patterns abuse exactly the kind of access browser_upload_file gives an agent:

POLICY

How to control browser_upload_file

PolicyLayer is an MCP gateway — it sits between your AI agents and Amazon Bedrock Knowledge Base Retrieval MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for browser_upload_file:

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "browser_upload_file": {
      "limits": [
        {
          "counter": "browser_upload_file_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

browser_upload_file stays usable, but capped — an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.

Create a free account and register Amazon Bedrock Knowledge Base Retrieval MCP Server — nothing to install.
Add this policy — paste it, or build it visually.
Point your MCP client (Claude, Cursor, anything) at your gateway URL.

LIMIT THIS TOOL →

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EXPLORE

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Rate Limiting MCP Tool Calls: A Practical Guide →
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PolicyLayer vs alternatives → How deterministic, per-call MCP policy compares with gateways, identity layers, and authorisation platforms.

FAQ

Questions about browser_upload_file

What does the browser_upload_file tool do? +

browser_upload_file. It is categorised as a Write tool in the Amazon Bedrock Knowledge Base Retrieval MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on browser_upload_file? +

Register the Amazon Bedrock Knowledge Base Retrieval MCP Server MCP server in PolicyLayer and add a rule for browser_upload_file: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches Amazon Bedrock Knowledge Base Retrieval MCP Server. Nothing to install.

What risk level is browser_upload_file? +

browser_upload_file is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.

Can I rate-limit browser_upload_file? +

Yes. Add a rate_limit block to the browser_upload_file rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.

How do I block browser_upload_file completely? +

Set action: deny in the PolicyLayer policy for browser_upload_file. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.

What MCP server provides browser_upload_file? +

browser_upload_file is provided by the Amazon Bedrock Knowledge Base Retrieval MCP Server MCP server (awslabs.bedrock-kb-retrieval-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every Amazon Bedrock Knowledge Base Retrieval MCP Server tool call.

Start from Amazon Bedrock Knowledge Base Retrieval MCP Server, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.

CHECK YOUR STACK →

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805 Amazon Bedrock Knowledge Base Retrieval MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.