List all municipalities (city / ward / town / village) in a Japanese prefecture, with their Soumu city codes. Prefecture name accepts kanji, katakana, or romaji. Shares the same in-memory dataset as search_by_address.
AI agents call list_cities_in_prefecture to retrieve information from jpzip MCP server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves and queries existing data (municipalities and their Soumu city codes) from a Japanese postal code dataset without creating, modifying, deleting, or executing external operations. It has no side effects and poses minimal security risk beyond potential information disclosure, which is typical of read operations on public datasets.
From the tool's definition Tool description states it 'List all municipalities' in a prefecture, which is a retrieval operation with no modification or side effects. The verb 'list' and the context of querying an in-memory dataset confirms this is a read-only operation.
Attacks that exploit this kind of access
List all municipalities (city / ward / town / village) in a Japanese prefecture, with their Soumu city codes. Prefecture name accepts kanji, katakana, or romaji. Shares the same in-memory dataset as search_by_address. It is categorised as a Read tool in the jpzip MCP server MCP Server, which means it retrieves data without modifying state.
Register the jpzip MCP server MCP server in PolicyLayer and add a rule for list_cities_in_prefecture: 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 jpzip MCP server. Nothing to install.
list_cities_in_prefecture 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_cities_in_prefecture 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_cities_in_prefecture. 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_cities_in_prefecture is provided by the jpzip MCP server MCP server (jpzip/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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