recency_filter · Perplexity MCP Server MCP: Risk & Policy

WHAT IT DOES

What recency_filter does on Perplexity MCP Server

AI agents use recency_filter to create or update resources in Perplexity MCP Server — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Perplexity MCP Server environment.

WHY IT NEEDS A POLICY

Why recency_filter needs a policy

This tool writes/modifies a persistent search filter configuration (recency/time window). It doesn't retrieve data itself, but changes state that persists and affects future queries. Since it modifies configuration state reversibly (can be changed or cleared), Write is the appropriate category. Severity is low as it only affects search filtering scope, not any sensitive data.

From the tool's definition 'Control the time window for search results' and 'Filter persists until changed' — modifies a persistent filter state that affects subsequent searches.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

recency_filter Rate-limited

recency_filter 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.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "recency_filter": {
      "limits": [
        {
          "counter": "recency_filter_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

LIMIT THIS TOOL →

Instant setup, no code required.

PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches Perplexity MCP Server, so you can run agents against it safely.

FAQ

Questions about recency_filter

What does the recency_filter tool do? +

Control the time window for search results. Essential for time-sensitive queries like news, updates, or recent developments. Filter persists until changed. It is categorised as a Write tool in the Perplexity MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on recency_filter? +

Register the Perplexity MCP Server MCP server in PolicyLayer and add a rule for recency_filter: 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 Perplexity MCP Server. Nothing to install.

What risk level is recency_filter? +

recency_filter is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.

Can I rate-limit recency_filter? +

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

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

recency_filter is provided by the Perplexity MCP Server MCP server (rossh121/perplexity-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.