AI agents call show_library_card to retrieve information from Steam-MCP without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool queries and displays user library data without modifying state, executing commands, or causing irreversible changes. It is a presentation/read operation retrieving game ownership information. The requirement for an API key is a security measure but does not change the underlying read-only nature of the operation.
From the tool's definition Tool name and description indicate 'show_library_card' displays a 'owned games summary' – a read-only retrieval of existing data (game library owned by a user). No creation, modification, deletion, code execution, or financial transaction is described.
Attacks that exploit this kind of access
Prefab card: owned games summary (requires API key). It is categorised as a Read tool in the Steam-MCP MCP Server, which means it retrieves data without modifying state.
Register the Steam- MCP server in PolicyLayer and add a rule for show_library_card: 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 Steam-MCP. Nothing to install.
show_library_card 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 show_library_card 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 show_library_card. 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.
show_library_card is provided by the Steam- MCP server (sandraschi/steam-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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