AI agents use set_values to create or update resources in FiftyOne MCP Server — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your FiftyOne MCP Server environment.
This tool modifies data across multiple samples in a computer vision dataset. While reversible (values can be reassigned), bulk operations on potentially large datasets carry significant risk if an AI agent applies incorrect transformations.
From the tool's definition Tool name is 'set_values' with description 'Bulk-assign values to a field across multiple' samples—this performs bulk modification of data fields. The term 'assign values' indicates creation or modification of data in a reversible manner.
Documented attack patterns abuse exactly the kind of access set_values gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and FiftyOne MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for set_values:
{
"version": "1",
"default": "deny",
"tools": {
"set_values": {
"limits": [
{
"counter": "set_values_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}set_values 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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Bulk-assign values to a field across multiple. It is categorised as a Write tool in the FiftyOne MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the FiftyOne MCP Server MCP server in PolicyLayer and add a rule for set_values: 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 FiftyOne MCP Server. Nothing to install.
set_values 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 set_values 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 set_values. 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.
set_values is provided by the FiftyOne MCP Server MCP server (voxel51/fiftyone-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from FiftyOne MCP Server, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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47 FiftyOne MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.