AI agents call groupsList to retrieve information from Telegram MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool queries and returns a list of group chats and supergroups that the Telegram account has access to. It performs a read-only operation with no side effects, does not execute commands, does not modify data, and does not involve financial transactions. The scope is limited to enumerating existing groups, making it a straightforward Read operation with low severity even if misused by an AI agent.
From the tool's definition Tool name 'groupsList' and description 'Lists group chats and supergroups' indicate a retrieval operation with no modification or execution of code.
Documented attack patterns abuse exactly the kind of access groupsList gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Telegram MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for groupsList:
{
"version": "1",
"default": "deny",
"tools": {
"groupsList": {}
}
}groupsList is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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Lists group chats and supergroups. It is categorised as a Read tool in the Telegram MCP Server MCP Server, which means it retrieves data without modifying state.
Register the Telegram MCP Server MCP server in PolicyLayer and add a rule for groupsList: 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 Telegram MCP Server. Nothing to install.
groupsList 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 groupsList 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 groupsList. 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.
groupsList is provided by the Telegram MCP Server MCP server (kfastov/tgcli). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Telegram 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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38 Telegram MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.