septa_train_view

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

The readOnlyHint annotation already signals safe read-only operation. The description adds valuable behavioral context by specifying what data is returned (GPS coordinates, line, destination, current/next stop, delay minutes) and that it covers every active train. It does not mention rate limits or data freshness, but with the annotation covering safety, this is adequate.

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?

The description is two sentences, front-loaded with the core purpose, and each sentence earns its place: the first states what it does, the second lists the returned fields. No wasted words.

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?

With no output schema, the description explains the return values (GPS coordinates, line, destination, current/next stop, delay minutes) sufficiently for an agent to know what to expect. It could add caveats like update frequency or data truncation, but for a simple 0-parameter read-only tool, it is reasonably complete.

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 has zero parameters, so the baseline is 4 per the rubric. The description adds no parameter information, but none is needed since the tool takes no inputs.

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 uses a specific verb ('Get') and clearly identifies the resource: all active SEPTA regional rail train positions. It also lists the exact data returned, distinguishing it from sibling tools like septa_bus_view (buses) and septa_next_to_arrive (arrivals) by focusing on train positions.

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?

The description implies when to use this tool (when you need real-time SEPTA train positions) but does not explicitly mention alternatives or exclusions. It lacks direct guidance such as 'for bus positions, use septa_bus_view' or 'for station arrivals, use septa_next_to_arrive', so context is present but not fully developed.

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