AI agents use update_skill to create or update resources in Forgetful — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Forgetful environment.
The 'update_' prefix clearly indicates a write/modification operation, not a read or destructive action. Update operations are reversible (unlike delete), placing this in Write rather than Destructive. Severity is medium because uncontrolled skill modifications could corrupt an AI agent's learned knowledge base, but the impact is bounded to skill records and reversible.
From the tool's definition Tool name 'update_skill' combined with sibling destructive/write operations (create_skill, delete_skill suggest a data modification API).
Documented attack patterns abuse exactly the kind of access update_skill gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Forgetful, and nothing reaches the server without passing your rules. This is the rule we recommend for update_skill:
{
"version": "1",
"default": "deny",
"tools": {
"update_skill": {
"limits": [
{
"counter": "update_skill_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}update_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.
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update_skill. It is categorised as a Write tool in the Forgetful MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Forgetful MCP server in PolicyLayer and add a rule for update_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 Forgetful. Nothing to install.
update_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 update_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 update_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.
update_skill is provided by the Forgetful MCP server (scottrbk/forgetful). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 59 Forgetful tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
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59 Forgetful tools catalogued and risk-classified — across an index of 42,500+ MCP servers.