AI agents use putObjectSourceUrl 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.
The tool downloads external content and writes it to persistent cloud storage, modifying the bucket's contents. This is a Write operation rather than Read (it modifies data), Execute (it's not running arbitrary code/commands, but performing a specific storage operation), or Destructive (it doesn't irreversibly delete data).
From the tool's definition Tool description states it downloads a file via URL and uploads the file to a storage bucket ('通过 url下载文件并将文件上传到存储桶'). This is a create/modify operation that writes data to cloud object storage.
Documented attack patterns abuse exactly the kind of access putObjectSourceUrl gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Tencent Cloud COS MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for putObjectSourceUrl:
{
"version": "1",
"default": "deny",
"tools": {
"putObjectSourceUrl": {
"limits": [
{
"counter": "putobjectsourceurl_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}putObjectSourceUrl 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.
Free to start. No card required.
通过 url下载文件并将文件上传到存储桶. 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 putObjectSourceUrl: 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.
putObjectSourceUrl 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 putObjectSourceUrl 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 putObjectSourceUrl. 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.
putObjectSourceUrl is provided by the Tencent Cloud COS MCP Server MCP server (tencent/cos-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 21 Tencent Cloud COS MCP Server tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
Free to start. No card required.
21 Tencent Cloud COS MCP Server tools catalogued and risk-classified — across an index of 42,500+ MCP servers.