Skills you own — free ones you've acquired and paid ones you've purchased.
AI agents call marketplace_library to retrieve information from Loreto without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves or lists user-owned skills from a marketplace library. It performs a query operation with no side effects—no data is created, modified, deleted, or executed. The action is purely informational, making it a Read category tool with low severity.
From the tool's definition Tool name 'marketplace_library' and description 'Skills you own — free ones you've acquired and paid ones you've purchased' indicate retrieval of owned skills inventory. Verbs imply querying/listing existing data without modification or execution.
Documented attack patterns abuse exactly the kind of access marketplace_library gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Loreto, and nothing reaches the server without passing your rules. This is the rule we recommend for marketplace_library:
{
"version": "1",
"default": "deny",
"tools": {
"marketplace_library": {}
}
}marketplace_library is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
Free to start. No card required.
Skills you own — free ones you've acquired and paid ones you've purchased. It is categorised as a Read tool in the Loreto MCP Server, which means it retrieves data without modifying state.
Register the Loreto MCP server in PolicyLayer and add a rule for marketplace_library: 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 Loreto. Nothing to install.
marketplace_library 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 marketplace_library 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 marketplace_library. 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.
marketplace_library is provided by the Loreto MCP server (kopias/loreto-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Loreto, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
Free to start. No card required.
13 Loreto tools catalogued and risk-classified — across an index of 43,000+ MCP servers.