Generate a presigned URL for downloading an object from S3
AI agents call s3_presign_get to retrieve information from AWS S3 MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves data (generates a URL to download S3 objects) with no side effects on the object itself. While presigned URLs can be shared and potentially expose data if misused by an agent, the tool itself performs read-only operations.
From the tool's definition Tool name is 's3_presign_get' and description states it 'Generate a presigned URL for downloading an object from S3'. The verb 'downloading' and suffix '_get' indicate data retrieval without modification.
Attacks that exploit this kind of access
Generate a presigned URL for downloading an object from S3. It is categorised as a Read tool in the AWS S3 MCP Server MCP Server, which means it retrieves data without modifying state.
Register the AWS S3 MCP Server MCP server in PolicyLayer and add a rule for s3_presign_get: 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 AWS S3 MCP Server. Nothing to install.
s3_presign_get is a Read tool with low risk. Read-only tools are generally safe to allow by default.
Yes. Add a rate_limit block to the s3_presign_get 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.
Set action: deny in the PolicyLayer policy for s3_presign_get. 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.
s3_presign_get is provided by the AWS S3 MCP Server MCP server (khuynh22/aws-s3-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Every MCP server has a record like this.
Type a name, get the same breakdown: verified identity, auth posture, risk grade, capabilities, recommended policy.
Teams ship this data inside their own products. See what a licence covers →