Server Quality Checklist

Tool Scores

• find_vehicleA
  3.5/5.0
  Behavior3/5

  Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

  Annotations already declare readOnlyHint=true and openWorldHint=true. The description adds useful behavioral context by specifying the return data (GPS coordinates, heading, speed, occupancy, next scheduled stop) and noting that the stop is included 'when available'. It does not contradict annotations, and the mention of 'when available' aligns with the open-world hint. However, it does not disclose behavior such as what happens when no match is found or whether both vehicle and route are allowed.

  Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

  Conciseness5/5

  Is the description appropriately sized, front-loaded, and free of redundancy?

  The description is two sentences, front-loaded with the primary purpose and immediately followed by usage examples. Every word contributes to understanding the tool's behavior and parameters. There is no redundant or filler content.

  Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

  Completeness3/5

  Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

  The description covers the main usage patterns (vehicle- and route-based lookup) and mentions the output fields. However, it does not specify behavior when both vehicle and route are provided, when neither is provided, or how the mode parameter applies. Given the existence of an output schema, the missing parameter-precedence details are a gap that could lead to incorrect usage.

  Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

  Parameters3/5

  Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

  The input schema already provides descriptions for all three parameters (mode, route, vehicle). The description adds extra meaning by explaining the mutually exclusive use of vehicle vs. route ('Give vehicle for a vehicle number... or route to get every vehicle'). It does not clarify the mode parameter or interaction between fields, so the added value over the schema is limited.

  Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

  Purpose5/5

  Does the description clearly state what the tool does and how it differs from similar tools?

  The description starts with a specific verb ('Locate'), names the resource ('a specific CATS bus or train'), and states the output ('current GPS coordinates'). It also distinguishes two search modes (by vehicle number or by route) and clarifies the scope ('every vehicle currently running a route'). This clearly differentiates it from siblings like list_vehicles and get_arrivals, which likely list all or handle scheduled times.

  Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

  Usage Guidelines2/5

  Does the description explain when to use this tool, when not to, or what alternatives exist?

  The description gives parameter usage instructions ('Give vehicle for a vehicle number... or route to get every vehicle') but provides no guidance on when to choose this tool over list_vehicles or get_arrivals. It does not mention exclusions, alternatives, or when the tool is not appropriate, leaving the agent to infer tool selection from the name alone.

  Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

• list_vehiclesA
  3.8/5.0
  Behavior3/5

  Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

  Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is established. The description adds the behavioral fact that it returns 'current' coordinates and only vehicles 'in service,' which clarifies the data scope. It does not go beyond that (e.g., mention of latency, rate limits, or pagination), so it makes a modest addition beyond the annotations.

  Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

  Conciseness5/5

  Is the description appropriately sized, front-loaded, and free of redundancy?

  The description is two sentences with no waste. The core action is front-loaded ('Return the current GPS coordinates...'), and the optional filters are mentioned compactly. Everything written earns its place, making it highly efficient for an agent to parse.

  Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

  Completeness4/5

  Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

  An output schema is present, so return format details are not needed in the description. The tool is a simple listing operation with optional filters; the description covers the essence, and the schema covers parameters. The only minor gap is the lack of explicit mention of potential limits (like pagination), but the limit parameter and output schema mitigate this. Overall, it is sufficiently complete for an agent to invoke correctly.

  Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

  Parameters3/5

  Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

  Schema description coverage is 67%, meaning most parameters already have meaning in the schema (mode, limit, and route each have descriptions). The description repeats these filters ('buses or trains', 'single route') without adding extra semantics like value formats or edge cases. Since the schema already covers the parameters, the baseline of 3 is appropriate.

  Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

  Purpose5/5

  Does the description clearly state what the tool does and how it differs from similar tools?

  The description states a specific verb ('Return'), a clear resource ('GPS coordinates of every CATS bus and train in service'), and explicitly distinguishes this from a single-vehicle lookup ('every'). It also mentions optional filters, which makes the tool's scope unmistakable and separates it from the sibling find_vehicle.

  Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

  Usage Guidelines3/5

  Does the description explain when to use this tool, when not to, or what alternatives exist?

  The description says 'Optionally filter to buses or trains, or to a single route,' which gives clear context on how to narrow results. However, it does not explicitly state when to prefer this tool over siblings like find_vehicle (e.g., 'for all vehicles, use this; for a specific one, use find_vehicle'). The 'every' phrasing implies bulk listing but does not name alternatives or exclusions.

  Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

• get_arrivalsA
  3.9/5.0
  Behavior3/5

  Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

  The annotations already declare readOnlyHint and openWorldHint; the description helps confirm these by saying 'Estimated'. It adds no operational limitations beyond what the schema provides, and it doesn't mention any rate limits, pagination, or fallback/ambiguous name handling. It does add 'service alerts' as a kind of output, which is lightly useful, so the description is adequate but not deep.

  Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

  Conciseness5/5

  Is the description appropriately sized, front-loaded, and free of redundancy?

  Two sentences capture the main purpose, input flexibility, and key fields. The most important information is placed first. No filler is present.

  Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

  Completeness5/5

  Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

  For a read-only tool with four parameters fully documented in the schema and an output schema present, the description provides enough context for an agent to know what the tool is for, what it accepts, and what it returns. It does not need to restate schemas because those are adjacent.

  Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

  Parameters3/5

  Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

  The schema has 100% coverage of four parameters, each with its own description. The text like 'stop id, stop code, or part of a stop name' mainly restates the schema's stop description. It adds no extra meaning for limit, mode, or route, so meaning comes primarily from the schema itself.

  Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

  Purpose5/5

  Does the description clearly state what the tool does and how it differs from similar tools?

  The description names the resource ('estimated arrival times of buses or trains') and the specific action ('at a specific stop or station'), making the tool's function explicit. It also lists the input formats and useful output fields, which differentiates it from sibling tools find_vehicle and list_vehicles.

  Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

  Usage Guidelines3/5

  Does the description explain when to use this tool, when not to, or what alternatives exist?

  It implies when to use the tool (when you need arrival times at a stop), but it never states an explicit 'when-not-to-use' or contrasts with siblings. No exclusions are given, so an agent can infer intent, but someone selecting among the three siblings must rely on whatever context the user provides without extra guidance.

  Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.