Returns the nearest bus heading to the anchor stop, with ETA and the bus
AI agents call bus_list_line_buses 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 is a straightforward read-only query tool that fetches real-time public transit information. It retrieves bus location and arrival data without creating, modifying, or deleting any resources. The data returned (ETA, vehicle position) has no side effects. Even if misused by an AI agent, it only exposes public transit information already available to the general public, posing minimal risk.
From the tool's definition Tool returns data about bus arrival times and positions ('nearest bus heading to the anchor stop, with ETA and the bus'). The verbs 'Returns' and 'get' in the tool name indicate data retrieval with no modification.
Documented attack patterns abuse exactly the kind of access bus_list_line_buses 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_list_line_buses:
{
"version": "1",
"default": "deny",
"tools": {
"bus_list_line_buses": {}
}
}bus_list_line_buses 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.
Returns the nearest bus heading to the anchor stop, with ETA and the bus. 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_list_line_buses: 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_list_line_buses 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_list_line_buses 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_list_line_buses. 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_list_line_buses 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.