Upload a score to a Steam leaderboard via the partner API. Requires a publisher API key with server IP allowlisted in Steamworks partner settings.
AI agents use steam_uploadLeaderboardScore to create or update resources in Steam MCP Server — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Steam MCP Server environment.
This tool creates or modifies leaderboard score data, which is reversible (scores can be updated or removed by legitimate means). It does not delete data irreversibly, execute arbitrary code, or handle financial transactions. The 'Upload' action is a Write operation.
From the tool's definition Tool description explicitly states "Upload a score to a Steam leaderboard". The verb 'upload' indicates creation or modification of data (a leaderboard score entry).
Attacks that exploit this kind of access
Upload a score to a Steam leaderboard via the partner API. Requires a publisher API key with server IP allowlisted in Steamworks partner settings. It is categorised as a Write tool in the Steam MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Steam MCP Server MCP server in PolicyLayer and add a rule for steam_uploadLeaderboardScore: 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 Server. Nothing to install.
steam_uploadLeaderboardScore is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.
Yes. Add a rate_limit block to the steam_uploadLeaderboardScore 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 steam_uploadLeaderboardScore. 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.
steam_uploadLeaderboardScore is provided by the Steam MCP Server MCP server (tmhsdigital/steam-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
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