mcp_register
AI agents use mcp_register to create or update resources in SIN-Code MCP Server Builder Skill — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your SIN-Code MCP Server Builder Skill environment.
Based on the server description mentioning 'register' as one of its capabilities, this tool likely registers a new MCP server entry in some registry or catalog. Registration is a Write operation (creates a new record/entry). Severity is medium as registering a rogue server could affect discovery/ecosystem. Confidence is low because the tool description is empty, so this is inferred from context.
From the tool's definition Tool name 'mcp_register' on a server that 'scaffolds new MCP servers' and provides tools to 'register, publish, and audit servers'
Attacks that exploit this kind of access
mcp_register. It is categorised as a Write tool in the SIN-Code MCP Server Builder Skill MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the SIN-Code MCP Server Builder Skill MCP server in PolicyLayer and add a rule for mcp_register: 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 SIN-Code MCP Server Builder Skill. Nothing to install.
mcp_register is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.
Yes. Add a rate_limit block to the mcp_register 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 mcp_register. 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.
mcp_register is provided by the SIN-Code MCP Server Builder Skill MCP server (opensin-code/sin-code-mcp-server-builder-skill). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Every MCP server has a record like this.
Type a name, get the same breakdown: verified identity, auth posture, risk grade, capabilities, recommended policy.
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