Look up a specific SDK skill by ID or search by keyword. Returns full skill content for ID lookup, or matching skill metadata for keyword search.
Risk signalsAccepts freeform code/query input (query)
Part of the Mcp App Extension server.
Free to start. No card required.
AI agents call lookup_skill to retrieve information from Mcp App Extension without modifying any data. This is common in research, monitoring, and reporting workflows where the agent needs context before taking action. Because read operations don't change state, they are generally safe to allow without restrictions -- but you may still want rate limits to control API costs.
Even though lookup_skill only reads data, uncontrolled read access can leak sensitive information or rack up API costs. An agent caught in a retry loop could make thousands of calls per minute. A rate limit gives you a safety net without blocking legitimate use.
Read-only tools are safe to allow by default. No rate limit needed unless you want to control costs.
{
"version": "1",
"default": "deny",
"tools": {
"lookup_skill": {}
}
}See the full Mcp App Extension policy for all 8 tools.
These attack patterns abuse exactly the kind of access lookup_skill gives an agent. Each links to the full case and the policy that stops it:
Other read tools across the catalogue. The same approach applies to each: allow, with a rate cap to control cost.
Look up a specific SDK skill by ID or search by keyword. Returns full skill content for ID lookup, or matching skill metadata for keyword search.. It is categorised as a Read tool in the Mcp App Extension MCP Server, which means it retrieves data without modifying state.
Register the Mcp App Extension MCP server in PolicyLayer and add a rule for lookup_skill: 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 App Extension. Nothing to install.
lookup_skill 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 lookup_skill 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 lookup_skill. 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.
lookup_skill is provided by the Mcp App Extension MCP server (@stackable-labs/mcp-app-extension). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 8 Mcp App Extension tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
Free to start. No card required.
4,600+ MCP servers and 31,000+ tools scanned and risk-classified.