retrieve_theme
AI agents call retrieve_theme to retrieve information from OneMap MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
The tool appears to fetch or retrieve thematic data layers from Singapore's OneMap service. No side effects, modifications, deletions, or financial operations are implied. The server is described as providing 'access' to data rather than modifying it. Low severity because retrieving public mapping and demographic data poses minimal risk of harm from misuse by an AI agent.
From the tool's definition Tool name 'retrieve_theme' follows Read verb pattern (retrieve). Part of OneMap server that provides 'comprehensive access' to 'thematic layers' and 'public transport data'.
Attacks that exploit this kind of access
retrieve_theme. It is categorised as a Read tool in the OneMap MCP Server MCP Server, which means it retrieves data without modifying state.
Register the OneMap MCP Server MCP server in PolicyLayer and add a rule for retrieve_theme: 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 OneMap MCP Server. Nothing to install.
retrieve_theme 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 retrieve_theme 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 retrieve_theme. 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.
retrieve_theme is provided by the OneMap MCP Server MCP server (linzele/mcp-onemap). 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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