Get all available shadcn/ui v4 blocks with categorization
AI agents call list_blocks to retrieve information from Shadcn Ui without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool queries and returns a list of available UI blocks with their categories. It retrieves static or semi-static information from the shadcn/ui library without modifying, executing, or deleting any data. No side effects or external operations are triggered. This is a straightforward read operation with minimal security risk.
From the tool's definition Tool name 'list_blocks' and description 'Get all available shadcn/ui v4 blocks with categorization' indicate a retrieval/query operation with no data modification or execution. The verb 'Get' and context of listing UI components confirm read-only behavior.
Documented attack patterns abuse exactly the kind of access list_blocks gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Shadcn Ui, and nothing reaches the server without passing your rules. This is the rule we recommend for list_blocks:
{
"version": "1",
"default": "deny",
"tools": {
"list_blocks": {}
}
}list_blocks is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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Get all available shadcn/ui v4 blocks with categorization. It is categorised as a Read tool in the Shadcn Ui MCP Server, which means it retrieves data without modifying state.
Register the Shadcn Ui MCP server in PolicyLayer and add a rule for list_blocks: 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 Shadcn Ui. Nothing to install.
list_blocks 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 list_blocks 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 list_blocks. 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.
list_blocks is provided by the Shadcn Ui MCP server (jpisnice/shadcn-ui-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Shadcn Ui, 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.
10 Shadcn Ui tools catalogued and risk-classified — across an index of 43,000+ MCP servers.