AI agents call list_assistants to retrieve information from Telnyx MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves and enumerates existing AI assistants without creating, modifying, deleting, or executing any operations. It is a straightforward read operation with minimal blast radius if misused by an agent—at worst, an agent learns about available assistants but cannot act on them without additional tools.
From the tool's definition Tool name 'list_assistants' and description 'List all AI Assistants' indicate a query/retrieval operation with no modification or side effects.
Documented attack patterns abuse exactly the kind of access list_assistants gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Telnyx MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for list_assistants:
{
"version": "1",
"default": "deny",
"tools": {
"list_assistants": {}
}
}list_assistants is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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List all AI Assistants. It is categorised as a Read tool in the Telnyx MCP Server MCP Server, which means it retrieves data without modifying state.
Register the Telnyx MCP Server MCP server in PolicyLayer and add a rule for list_assistants: 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 Telnyx MCP Server. Nothing to install.
list_assistants 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 list_assistants 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 list_assistants. 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.
list_assistants is provided by the Telnyx MCP Server MCP server (team-telnyx/telnyx-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Telnyx 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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46 Telnyx MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.