Upload a file to Stage with text content
AI agents use stage_upload_file to create or update resources in SingleStore MCP Server — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your SingleStore MCP Server environment.
The tool creates new file resources in a staging environment. This is a Write action (not Read, as it modifies state; not Destructive, as uploads are reversible; not Execute, as it doesn't run code or commands). Severity is medium because uncontrolled file uploads could fill storage, introduce malicious content into pipelines, or be used to stage data for subsequent harmful operations.
From the tool's definition Tool description states 'Upload a file to Stage with text content' - this creates/adds a file resource to a staging area, which is a reversible write operation.
Documented attack patterns abuse exactly the kind of access stage_upload_file gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and SingleStore MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for stage_upload_file:
{
"version": "1",
"default": "deny",
"tools": {
"stage_upload_file": {
"limits": [
{
"counter": "stage_upload_file_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}stage_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.
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Upload a file to Stage with text content. It is categorised as a Write tool in the SingleStore MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the SingleStore MCP Server MCP server in PolicyLayer and add a rule for stage_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 SingleStore MCP Server. Nothing to install.
stage_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 stage_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 stage_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.
stage_upload_file is provided by the SingleStore MCP Server MCP server (singlestore-labs/mcp-server-singlestore). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 24 SingleStore MCP Server tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
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24 SingleStore MCP Server tools catalogued and risk-classified — across an index of 42,500+ MCP servers.