set_favorite_blog · MCP RSS MCP: Risk & Policy

WHAT IT DOES

What set_favorite_blog does on MCP RSS

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

WHY IT NEEDS A POLICY

Why set_favorite_blog needs a policy

set_favorite_blog creates or modifies user preference metadata (favorite status) which is a Write operation—reversible configuration of the reading interface. It has no Read-only characteristics (it modifies state), is not Destructive (favorites can be unmarked), does not Execute arbitrary code, and has no Financial implications.

From the tool's definition Tool description explicitly states it marks a blog/feed as favorite or removes from favorites, modifying metadata about feed preferences.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

set_favorite_blog Rate-limited

set_favorite_blog 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": {
    "set_favorite_blog": {
      "limits": [
        {
          "counter": "set_favorite_blog_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 MCP RSS, so you can run agents against it safely.

FAQ

Questions about set_favorite_blog

What does the set_favorite_blog tool do? +

Mark a blog/feed as favorite or remove from favorites. Favorite blogs appear first in get_sources and can be prioritized/filtered in get_content/search_articles. Use to: highlight preferred blogs, create reading priorities, filter by favorites. Get feed IDs from get_sources first. Workflow: (1) get_sources to find feed ID, (2) set_favorite_blog to mark it, (3) use favoriteBlogsOnly or prioritizeFavoriteBlogs filters. It is categorised as a Write tool in the MCP RSS MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on set_favorite_blog? +

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

What risk level is set_favorite_blog? +

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

Can I rate-limit set_favorite_blog? +

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

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

set_favorite_blog is provided by the MCP RSS MCP server (ronnycoding/my_mcp_rss). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.