pf_search

THE RISK

Low Risk

Why pf_search needs a policy

This tool retrieves and queries federated social network data (accounts, hashtags, statuses) with no capability to create, modify, or delete content. WebFinger resolution is a standard federated identity lookup mechanism. The rate-limiting confirms it is a safe read operation. No side effects or state changes are possible.

From the tool's definition Tool name 'pf_search' and description 'Search accounts / hashtags / statuses' indicate data retrieval operations. The mention of 'Remote queries resolve via WebFinger' confirms lookup/query behavior without modification.

Documented attack patterns abuse exactly the kind of access pf_search gives an agent:

POLICY

How to control pf_search

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 pf_search:

policy.json

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

pf_search is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.

Create a free account and register Crow — nothing to install.
Add this policy — paste it, or build it visually.
Point your MCP client (Claude, Cursor, anything) at your gateway URL.

CAP THIS TOOL →

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EXPLORE

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Go deeper

The MCP Attack Database → Documented attack patterns against MCP deployments — and the policies that stop them.
Data exfiltration → How read access becomes an exfiltration channel when chained with untrusted content.
MCP token cost → What connecting this server costs in context-window tokens on every request.
Rate Limiting MCP Tool Calls: A Practical Guide →
MCP Security: Why Prompt Guardrails Aren't Enough →

FAQ

Questions about pf_search

What does the pf_search tool do? +

Search accounts / hashtags / statuses. Remote queries resolve via WebFinger. Rate-limited: 60/hour. 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 pf_search? +

Register the Crow MCP server in PolicyLayer and add a rule for pf_search: 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 pf_search? +

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

Can I rate-limit pf_search? +

Yes. Add a rate_limit block to the pf_search 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 pf_search completely? +

Set action: deny in the PolicyLayer policy for pf_search. 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 pf_search? +

pf_search 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.

Enforce policy on every Crow tool call.

Start from Crow, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.

CHECK YOUR STACK →