AI agents call skill_search_index to retrieve information from ClaudeSkills MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool is clearly designed for searching or querying an index of skills, consistent with the read/discovery purpose of the server. No modification, execution, deletion, or financial impact is indicated. The empty description prevents higher confidence, but the context strongly supports Read classification.
From the tool's definition Tool name 'skill_search_index' combined with server description stating the server 'Exposes Anthropic Claude Agent Skills as MCP tools for discovery, search, and reading skill guidance and assets.' The verb 'search' indicates querying or retrieval without…
Documented attack patterns abuse exactly the kind of access skill_search_index gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and ClaudeSkills MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for skill_search_index:
{
"version": "1",
"default": "deny",
"tools": {
"skill_search_index": {}
}
}skill_search_index is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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skill_search_index. It is categorised as a Read tool in the ClaudeSkills MCP Server MCP Server, which means it retrieves data without modifying state.
Register the ClaudeSkills MCP Server MCP server in PolicyLayer and add a rule for skill_search_index: 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 ClaudeSkills MCP Server. Nothing to install.
skill_search_index is a Read tool with low risk. Read-only tools are generally safe to allow by default.
Yes. Add a rate_limit block to the skill_search_index 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.
Set action: deny in the PolicyLayer policy for skill_search_index. 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.
skill_search_index is provided by the ClaudeSkills MCP Server MCP server (tsoernes/skills-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from ClaudeSkills 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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13 ClaudeSkills MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.