Fetch posts. type_: Subscribed (follows), Local (this instance), All (federated). Rate-limited: 60/hour.
AI agents call lemmy_feed to retrieve information from Crow without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves or queries posts from a Lemmy instance without modifying, executing, or deleting any data. It is a straightforward data retrieval operation with no destructive or side-effecting capabilities. The blast radius from misuse is minimal—at worst, an AI agent could flood the rate limit or retrieve unwanted post data, neither of which causes lasting harm.
From the tool's definition Tool name 'lemmy_feed' and description 'Fetch posts' with options for Subscribed, Local, or All indicate a read-only retrieval operation. The rate limiting (60/hour) suggests a straightforward query endpoint with no side effects.
Documented attack patterns abuse exactly the kind of access lemmy_feed gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Crow, and nothing reaches the server without passing your rules. This is the rule we recommend for lemmy_feed:
{
"version": "1",
"default": "deny",
"tools": {
"lemmy_feed": {}
}
}lemmy_feed is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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Fetch posts. type_: Subscribed (follows), Local (this instance), All (federated). Rate-limited: 60/hour. It is categorised as a Read tool in the Crow MCP Server, which means it retrieves data without modifying state.
Register the Crow MCP server in PolicyLayer and add a rule for lemmy_feed: 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.
lemmy_feed 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 lemmy_feed 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 lemmy_feed. 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.
lemmy_feed 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.
Start from Crow, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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576 Crow tools catalogued and risk-classified — across an index of 43,000+ MCP servers.