crow_upload_file
Upload a small file (base64, <1MB) or get an HTTP upload URL for larger files. When project_id is set, the upload is gated on write_files capability and the s3 key is scoped under the project
This record as markdown: /tools/kh0pper-crow/crow-upload-file.md
What crow_upload_file does on Crow
AI agents use crow_upload_file to create or update resources in Crow, usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Crow environment.
Why crow_upload_file is rated Medium
This tool creates new files or data in a storage system (S3). When scoped to a project_id, writes are permission-gated on write_files capability. The action is reversible (files can be deleted), so it is Write rather than Destructive.
From the tool's definition Tool description states 'Upload a small file (base64, <1MB) or get an HTTP upload URL for larger files' and 'the upload is gated on write_files capability', indicating creation/modification of data in storage
Attacks that exploit this kind of access
The rule that runs crow_upload_file safely
PolicyLayer is an MCP gateway: it sits between your AI agents and Crow, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For crow_upload_file, this is the rule to start with:
crow_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.
The button opens the PolicyLayer dashboard: create your workspace, connect Crow, apply this rule, and every crow_upload_file call is checked against it from then on.
Questions about crow_upload_file
Upload a small file (base64, <1MB) or get an HTTP upload URL for larger files. When project_id is set, the upload is gated on write_files capability and the s3 key is scoped under the project. It is categorised as a Write tool in the Crow MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Crow MCP server in PolicyLayer and add a rule for crow_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 Crow. Nothing to install.
crow_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 crow_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 crow_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.
crow_upload_file is provided by the Crow MCP server (kh0pper/crow). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
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