AI agents call hello to retrieve information from MCP TypeScript Starter without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool performs a basic informational action—greeting the user—with no side effects, no data modifications, and no external operations. It is purely a read/output operation with minimal blast radius.
From the tool's definition Tool name 'hello' and description 'Say hello to a person' indicate a simple greeting function that retrieves or outputs a message without modifying any state or triggering external operations.
Documented attack patterns abuse exactly the kind of access hello gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and MCP TypeScript Starter, and nothing reaches the server without passing your rules. This is the rule we recommend for hello:
{
"version": "1",
"default": "deny",
"tools": {
"hello": {}
}
}hello 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 a person. It is categorised as a Read tool in the MCP TypeScript Starter MCP Server, which means it retrieves data without modifying state.
Register the MCP TypeScript Starter MCP server in PolicyLayer and add a rule for hello: 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 MCP TypeScript Starter. Nothing to install.
hello 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 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. 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 is provided by the MCP TypeScript Starter MCP server (sammorrowdrums/mcp-typescript-starter). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from MCP TypeScript Starter, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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8 MCP TypeScript Starter tools catalogued and risk-classified — across an index of 43,000+ MCP servers.