add_stopwords

THE RISK

Medium Risk

Why add_stopwords needs a policy

This tool creates or modifies index configuration data (stopwords) reversibly. While it doesn't delete or execute arbitrary code, it does alter the search behavior of an index, which could be used maliciously to degrade search quality or hide/surface unwanted results. The modification is reversible (stopwords can presumably be removed), placing it in the Write category rather than Destructive.

From the tool's definition The tool description states it 'Add[s] custom stopwords to an index', which modifies the configuration of an existing index by appending to its stopword dictionary.

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

POLICY

How to control add_stopwords

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

policy.json

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

add_stopwords 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.

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

LIMIT THIS TOOL →

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EXPLORE

Related tools and policies

More Searchcraft MCP Server tools

Destructive delete_all_documents Delete all documents from an index. The index will continue to exist after all documents a Destructive delete_all_keys Delete all authentication keys on the Searchcraft cluster. Use with extreme caution! Destructive delete_all_stopwords Delete all custom stopwords from an index. This only affects custom stopwords, not the def Destructive delete_all_synonyms Delete all synonyms from an index. Destructive delete_document_by_id Delete a single document from an index by its internal Searchcraft ID (_id). Destructive delete_documents_by_field Delete one or several documents from an index by field term match (e.g., {id: Destructive delete_documents_by_query Delete one or several documents from an index by query match. Destructive delete_federation Delete a federation permanently.

All 48 Searchcraft MCP Server tools →

Write tools on other servers

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Go deeper

The MCP Attack Database → Documented attack patterns against MCP deployments — and the policies that stop them.
Argument validation → Checking tool call arguments against schema and policy before they run.
Scoped token → Per-person credentials that grant a defined subset of servers and tools.
Rate Limiting MCP Tool Calls: A Practical Guide →
MCP Security: Why Prompt Guardrails Aren't Enough →

FAQ

Questions about add_stopwords

What does the add_stopwords tool do? +

Add custom stopwords to an index. These are added on top of the default language-specific dictionary. It is categorised as a Write tool in the Searchcraft 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 add_stopwords? +

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

What risk level is add_stopwords? +

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

Can I rate-limit add_stopwords? +

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

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

add_stopwords is provided by the Searchcraft MCP Server MCP server (searchcraft-inc/searchcraft-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every Searchcraft MCP Server tool call.

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

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