Search inside a city by keyword. Returns matching lines, stations, and POIs in one call. Use this as the primary entry point when the user gives a line number, station name, or destination name without IDs. Keyword tip: plain
AI agents call bus_search to retrieve information from Chelaile without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool performs a read-only search operation against public transit data. It queries and returns information about bus lines, stations, and points of interest without any capability to modify, delete, or execute operations. The blast radius of misuse is minimal—an agent could only retrieve unwanted transit information, not cause harm to systems or data.
From the tool's definition Tool description states it 'Search inside a city by keyword. Returns matching lines, stations, and POIs in one call.' This is a search/query operation with no side effects—it retrieves data without creating, modifying, deleting, or executing anything.
Documented attack patterns abuse exactly the kind of access bus_search gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Chelaile, and nothing reaches the server without passing your rules. This is the rule we recommend for bus_search:
{
"version": "1",
"default": "deny",
"tools": {
"bus_search": {}
}
}bus_search is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
Free to start. No card required.
Search inside a city by keyword. Returns matching lines, stations, and POIs in one call. Use this as the primary entry point when the user gives a line number, station name, or destination name without IDs. Keyword tip: plain. It is categorised as a Read tool in the Chelaile MCP Server, which means it retrieves data without modifying state.
Register the Chelaile MCP server in PolicyLayer and add a rule for bus_search: 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 Chelaile. Nothing to install.
bus_search 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 bus_search 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 bus_search. 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.
bus_search is provided by the Chelaile MCP server (peanutsplash/chelaile-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Chelaile, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
Free to start. No card required.
15 Chelaile tools catalogued and risk-classified — across an index of 43,000+ MCP servers.