UPLOAD SINGLE FILE - Standard method for uploading one file to Gemini. BEST FOR: Single documents, images, or code files for immediate analysis. Includes automatic retry and state monitoring until file is ready. WORKFLOW: 1) Upload with auto-detected MIME type, 2) Wait for processing to complete ...
AI agents use upload_file to create or update resources in Gemini MCP Server — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Gemini MCP Server environment.
This tool creates new data in Gemini's file storage system, making it a Write operation rather than Read. While the files auto-delete after 48 hours (providing some reversibility), the action modifies system state by storing files.
From the tool's definition Tool performs 'UPLOAD SINGLE FILE' with description stating it uploads files and 'Returns: fileUri' indicating persistent storage creation. The action is reversible (files auto-delete after 48 hours per documentation).
Attacks that exploit this kind of access
UPLOAD SINGLE FILE - Standard method for uploading one file to Gemini. BEST FOR: Single documents, images, or code files for immediate analysis. Includes automatic retry and state monitoring until file is ready. WORKFLOW: 1) Upload with auto-detected MIME type, 2) Wait for processing to complete (usually 10-30 seconds), 3) Returns URI for chat tool. RETURNS: fileUri (pass to chat tool), displayName, mimeType, sizeBytes, state. Files auto-delete after 48 hours. For 2+ files, consider upload_multiple_files for efficiency. It is categorised as a Write tool in the Gemini MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Gemini MCP Server MCP server in PolicyLayer and add a rule for 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 Gemini MCP Server. Nothing to install.
upload_file is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.
Yes. Add a rate_limit block to the 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.
Set action: deny in the PolicyLayer policy for 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.
upload_file is provided by the Gemini MCP Server MCP server (mintmcqueen/gemini-mcp). 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 →