search_tags

THE RISK

Low Risk

Why search_tags needs a policy

This tool retrieves and queries data (tags) from the knowledge base with no side effects or modifications. It is a straightforward search/filter operation that returns a limited set of matching results. No data is created, modified, deleted, or irreversibly changed. The blast radius of misuse is minimal—worst case an agent could enumerate all tags, which is informational only.

From the tool's definition Tool performs a search operation to retrieve tags matching a query with optional limit, returning matching results without modifying data. Description explicitly states 'Search for tags' which is a read-only retrieval operation.

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

POLICY

How to control search_tags

PolicyLayer is an MCP gateway — it sits between your AI agents and Library MCP, and nothing reaches the server without passing your rules. This is the rule we recommend for search_tags:

policy.json

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

search_tags 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 Library MCP — 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 →

Free to start. No card required.

EXPLORE

Related tools and policies

More Library MCP tools

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All 7 Library MCP tools →

Read tools on other servers

M-Team MCP Server get_torrent_detail YouTube MCP Server search_channel Android Forensics ADB MCP Server parse_browser_history 0xarchive web3_challenge

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 search_tags

What does the search_tags tool do? +

Search for tags matching the provided query. Args: tag_query: partial or full tag name to search for limit: the maximum number of tags to return. It is categorised as a Read tool in the Library MCP MCP Server, which means it retrieves data without modifying state.

How do I enforce a policy on search_tags? +

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

What risk level is search_tags? +

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

Can I rate-limit search_tags? +

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

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

search_tags is provided by the Library MCP server (lethain/library-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every Library MCP tool call.

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

CHECK YOUR STACK →