This record as markdown: /tools/156554395-tx-cos-mcp/upload-file.md
What upload_file does on Tencent Cloud COS MCP Server
AI agents use upload_file to create or update resources in Tencent Cloud COS MCP Server, usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Tencent Cloud COS MCP Server environment.
Why upload_file is rated Medium
The tool creates or modifies data in cloud object storage by uploading files. This is a Write operation with high severity because unintended uploads could store malicious, sensitive, or corrupted files in production cloud storage, affecting availability and data integrity for applications relying on that storage.
From the tool's definition Tool name 'upload_file' and description '上传单个文件到腾讯云COS' (upload a single file to Tencent Cloud COS) directly indicate file creation/modification in cloud storage.
Attacks that exploit this kind of access
The rule that runs upload_file safely
PolicyLayer is an MCP gateway: it sits between your AI agents and Tencent Cloud COS MCP Server, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For upload_file, this is the rule to start with:
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 Tencent Cloud COS MCP Server, apply this rule, and every upload_file call is checked against it from then on.
Questions about upload_file
上传单个文件到腾讯云COS. It is categorised as a Write tool in the Tencent Cloud COS MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Tencent Cloud COS 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 Tencent Cloud COS 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 Tencent Cloud COS MCP Server MCP server (156554395/tx-cos-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
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