lemmy_list_communities

List communities. Default scope

SERVERCrow SOURCEkh0pper/crow

Low RISK CLASS

Category Read

Parameters 00 required

Recommended Allowedsee the rule below

Registry record Grade F, identity unverified Pull the record →

This record as markdown: /tools/kh0pper-crow/lemmy-list-communities.md

WHAT IT DOES

What lemmy_list_communities does on Crow

AI agents call lemmy_list_communities to retrieve information from Crow without modifying anything. It is typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.

RISK

Why lemmy_list_communities is rated Low

This tool retrieves or queries community data with no side effects. It matches the 'Read' category definition of listing data without modification, deletion, or external execution. The blast radius is minimal—listing communities typically returns public information with low risk of misuse.

From the tool's definition Tool name 'lemmy_list_communities' and description 'List communities' indicate a query/retrieval operation with 'List' being a classic read-only action. 'Default scope' suggests no elevated permissions.

Attacks that exploit this kind of access

RECOMMENDED RULE

The rule that runs lemmy_list_communities safely

PolicyLayer is an MCP gateway: it sits between your AI agents and Crow, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For lemmy_list_communities, this is the rule to start with:

lemmy_list_communities Allowed

lemmy_list_communities is read-only, so it stays allowed. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "lemmy_list_communities": {}
  }
}

ALLOW ONLY THIS TOOL → Instant setup, no code required.

The button opens the PolicyLayer dashboard: create your workspace, connect Crow, apply this rule, and every lemmy_list_communities call is checked against it from then on.

FAQ

Questions about lemmy_list_communities

What does the lemmy_list_communities tool do? +

List communities. Default scope. It is categorised as a Read tool in the Crow MCP Server, which means it retrieves data without modifying state.

How do I enforce a policy on lemmy_list_communities? +

Register the Crow MCP server in PolicyLayer and add a rule for lemmy_list_communities: 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 Crow. Nothing to install.

What risk level is lemmy_list_communities? +

lemmy_list_communities is a Read tool with low risk. Read-only tools are generally safe to allow by default.

Can I rate-limit lemmy_list_communities? +

Yes. Add a rate_limit block to the lemmy_list_communities 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.

How do I block lemmy_list_communities completely? +

Set action: deny in the PolicyLayer policy for lemmy_list_communities. 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.

What MCP server provides lemmy_list_communities? +

lemmy_list_communities is provided by the Crow MCP server (kh0pper/crow). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

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