Which transport operators have timetables here, and what each one covers.
This tool declares no required parameters. Add optional parameters from the input schema as needed.
{
"id": 1,
"jsonrpc": "2.0",
"method": "tools/call",
"params": {
"arguments": {},
"name": "transit_operators"
}
}| Name | Required | Description | Default |
|---|---|---|---|
No arguments | |||
| Name | Required | Description | Default |
|---|---|---|---|
No arguments | |||
Changes observed during successful MCP inspections.
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are supplied, so the description carries the burden. It implies a passive reference lookup, but never states that it is read-only, whether the list is static or filtered by region, or what 'covers' means (routes, modes, geographic area) — though the risk of misuse is low for a zero-parameter query.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
One front-loaded sentence with no filler, structured as 'what exists' plus 'what it covers.' The only blemish is the deictic 'here,' which is unanchored and slightly ambiguous in a multi-domain server.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
For a zero-parameter reference tool with an output schema, return values need no explanation, so the description is close to sufficient. What is missing is the scope the enumeration applies to (which region/network) and any hint that the returned operator names are useful inputs to the departure/trip tools.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
The tool takes zero parameters, which is the baseline-4 case; the schema is trivially complete. The description adds no parameter meaning because there is none to add, and it correctly does not pretend otherwise.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description states a specific resource (transport operators with timetables) and adds the scope 'what each one covers,' which tells the agent this is an enumeration of coverage, not a stop search or a departures lookup. It is clear without opening the schema, though it never names a sibling to contrast with and the word 'here' is left unexplained.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
There is no explicit when-to-use guidance: nothing says this is a discovery step to identify which operator/coverage exists before calling transit_departures, transit_trips_between, or transit_find_stops, and no conditions or exclusions are given. Usage is only weakly implied by the word 'timetables.'
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
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