AI agents use hide-tool to create or update resources in Dynamic MCP Server — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Dynamic MCP Server environment.
This tool modifies user-specific settings or access control lists by hiding tools, which is a reversible change to data state. It does not delete anything permanently (which would be Destructive), execute arbitrary operations (Execute), nor retrieve data without side effects (Read). The medium severity reflects that misuse could restrict a user's access, but the change is non-destructive and can be undone.
From the tool's definition Tool name 'hide-tool' and description 'Hide one or more tools for the current user' indicate modification of user preferences/permissions state. The action is reversible (tools can be unhidden), distinguishing it from deletion.
Documented attack patterns abuse exactly the kind of access hide-tool gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Dynamic MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for hide-tool:
{
"version": "1",
"default": "deny",
"tools": {
"hide-tool": {
"limits": [
{
"counter": "hide-tool_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}hide-tool 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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Hide one or more tools for the current user. It is categorised as a Write tool in the Dynamic MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Dynamic MCP Server MCP server in PolicyLayer and add a rule for hide-tool: 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 Dynamic MCP Server. Nothing to install.
hide-tool 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 hide-tool 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 hide-tool. 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.
hide-tool is provided by the Dynamic MCP Server MCP server (scitara-cto/dynamic-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Dynamic 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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18 Dynamic MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.