Create a post in a community. Either url (link post) or body (text post) must be set — or both. Rate-limited: 10/hour.
AI agents use lemmy_post to create or update resources in Crow — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Crow environment.
This tool creates new content (posts) in a Lemmy community, which is a reversible write operation. It modifies the state of the platform by adding data. Severity is medium because misuse could result in spam, misinformation, or reputation damage, but the effect is limited to a single community and posts can be deleted. The rate limiting (10/hour) provides some protection against automated abuse.
From the tool's definition Tool name 'lemmy_post' and description 'Create a post in a community' indicate data creation. Parameters allow 'url (link post) or body (text post)' creation with rate limiting.
Documented attack patterns abuse exactly the kind of access lemmy_post 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_post:
{
"version": "1",
"default": "deny",
"tools": {
"lemmy_post": {
"limits": [
{
"counter": "lemmy_post_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}lemmy_post stays usable, but capped — an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.
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Create a post in a community. Either url (link post) or body (text post) must be set — or both. Rate-limited: 10/hour. It is categorised as a Write tool in the Crow MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Crow MCP server in PolicyLayer and add a rule for lemmy_post: 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_post is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.
Yes. Add a rate_limit block to the lemmy_post 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_post. 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_post 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.
Free to start. No card required.
576 Crow tools catalogued and risk-classified — across an index of 43,000+ MCP servers.