AI agents call check_scope to retrieve information from Nuclei without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool performs a read-only lookup against HackerOne scope data to determine if a target is eligible. It has no side effects—it neither modifies data, executes code, deletes records, nor moves money. The primary risk is information disclosure if an unauthorized party queries scope details, but this is mitigated by the server's stated enforcement of scoping rules.
From the tool's definition Tool name 'check_scope' and description 'Check whether a target is in HackerOne scope and bounty-eligible' indicate a query/lookup operation that retrieves scope eligibility data without modifying, deleting, or executing operations.
Attacks that exploit this kind of access
Check whether a target is in HackerOne scope and bounty-eligible. It is categorised as a Read tool in the Nuclei MCP Server, which means it retrieves data without modifying state.
Register the Nuclei MCP server in PolicyLayer and add a rule for check_scope: 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 Nuclei. Nothing to install.
check_scope 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 check_scope 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 check_scope. 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.
check_scope is provided by the Nuclei MCP server (tobiasguta/nuclei-mcp). 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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