AI agents call list_vault_sites to retrieve information from Psamvault without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool performs a retrieval operation with no side effects, fitting the Read category. However, severity is elevated to 'high' because the output reveals the complete inventory of credential storage (what sites/services have credentials in the vault), which could be valuable reconnaissance for an attacker or enable social engineering attacks.
From the tool's definition Tool description explicitly states 'List all sites stored in the psamvault vault' — a read-only query operation that retrieves metadata about stored credentials without executing them or modifying data.
Attacks that exploit this kind of access
[🔐 Site Authentication] List all sites stored in the psamvault vault. It is categorised as a Read tool in the Psamvault MCP Server, which means it retrieves data without modifying state.
Register the Psamvault MCP server in PolicyLayer and add a rule for list_vault_sites: 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 Psamvault. Nothing to install.
list_vault_sites 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_vault_sites 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_vault_sites. 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_vault_sites is provided by the Psamvault MCP server (psam-717/psamvault-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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