AI agents call hello_world to retrieve information from D&D Knowledge Navigator without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This is a basic greeting tool that returns a simple hello message. It does not query data, modify state, execute code, delete information, or involve financial transactions. It represents the least invasive category of tool interaction.
From the tool's definition Tool named 'hello_world' with description 'Say hello to someone' performs a simple greeting operation that retrieves or outputs a static message with no side effects, modifications, or external operations.
Documented attack patterns abuse exactly the kind of access hello_world gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and D&D Knowledge Navigator, and nothing reaches the server without passing your rules. This is the rule we recommend for hello_world:
{
"version": "1",
"default": "deny",
"tools": {
"hello_world": {}
}
}hello_world is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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Say hello to someone. It is categorised as a Read tool in the D&D Knowledge Navigator MCP Server, which means it retrieves data without modifying state.
Register the D&D Knowledge Navigator MCP server in PolicyLayer and add a rule for hello_world: 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 D&D Knowledge Navigator. Nothing to install.
hello_world is a Read tool with low risk. Read-only tools are generally safe to allow by default.
Yes. Add a rate_limit block to the hello_world 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 hello_world. 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.
hello_world is provided by the D&D Knowledge Navigator MCP server (procload/dnd-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 14 D&D Knowledge Navigator tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
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14 D&D Knowledge Navigator tools catalogued and risk-classified — across an index of 42,500+ MCP servers.