AI agents call key_list to retrieve information from Semaphore without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves and displays a list of credential keys within a project. While credentials themselves are sensitive data, the tool merely queries/lists existing keys without creating, modifying, or deleting them. The act of listing is a read-only operation.
From the tool's definition Tool name 'key_list' and description 'List all keys (credentials) in a project' indicate a retrieval operation with no data modification or side effects.
Attacks that exploit this kind of access
List all keys (credentials) in a project. It is categorised as a Read tool in the Semaphore MCP Server, which means it retrieves data without modifying state.
Register the Semaphore MCP server in PolicyLayer and add a rule for key_list: 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 Semaphore. Nothing to install.
key_list 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 key_list 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 key_list. 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.
key_list is provided by the Semaphore MCP server (vitexsoftware/semaphore-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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