list_deleted_user_instances
AI agents call list_deleted_user_instances to retrieve information from Nebulablock without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
The 'list' prefix indicates a data retrieval operation with no side effects. Although the description is empty (lowering confidence slightly), the tool appears to query deleted instances for informational purposes. Even though it involves deleted instances, it only reads/retrieves historical records rather than performing destructive actions on current resources.
From the tool's definition Tool name 'list_deleted_user_instances' contains 'list', a verb associated with retrieval operations. The description is empty, but the name structure suggests querying historical/deleted instance data rather than modifying or removing data.
Attacks that exploit this kind of access
list_deleted_user_instances. It is categorised as a Read tool in the Nebulablock MCP Server, which means it retrieves data without modifying state.
Register the Nebulablock MCP server in PolicyLayer and add a rule for list_deleted_user_instances: 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 Nebulablock. Nothing to install.
list_deleted_user_instances 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_deleted_user_instances 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_deleted_user_instances. 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_deleted_user_instances is provided by the Nebulablock MCP server (nebula-block-data/nebulablock-mcp-server). 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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