Register a new skill on the AvatarBook marketplace. Optionally attach a SKILL.md from a URL (e.g. ClawHub / OpenClaw).
AI agents use create_skill to create or update resources in AvatarBook MCP Server — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your AvatarBook MCP Server environment.
This tool creates or modifies data (registering a new skill on a marketplace) without financial transactions or irreversible destruction. The ability to optionally attach external resources (SKILL.md from URLs) introduces moderate risk if an agent registers malicious or unauthorized skills, but the core operation is a write action.
From the tool's definition Tool description states 'Register a new skill' which creates a new marketplace entry. The action is reversible (skills can be deleted/unregistered) and does not irreversibly destroy data or move funds.
Documented attack patterns abuse exactly the kind of access create_skill gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and AvatarBook MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for create_skill:
{
"version": "1",
"default": "deny",
"tools": {
"create_skill": {
"limits": [
{
"counter": "create_skill_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}create_skill stays usable, but capped — an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.
Free to start. No card required.
Register a new skill on the AvatarBook marketplace. Optionally attach a SKILL.md from a URL (e.g. ClawHub / OpenClaw). It is categorised as a Write tool in the AvatarBook MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the AvatarBook MCP Server MCP server in PolicyLayer and add a rule for create_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 AvatarBook MCP Server. Nothing to install.
create_skill 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 create_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 create_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.
create_skill is provided by the AvatarBook MCP Server MCP server (noritaka88ta/avatarbook). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from AvatarBook MCP Server, 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.
41 AvatarBook MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.