Get Shinkansen train details

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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and non-destructive behavior, covering the safety profile. The description adds the 'ordered stops' detail, which hints at the response structure, but doesn't disclose additional side effects or edge cases. This is adequate given the strong annotation coverage.

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?

Two sentences, each earning its place. The primary usage instruction is front-loaded, and the warning about manual construction is a concise, valuable addition. No fluff.

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 single-parameter tool with an output schema available, the description covers the essential usage (source of ID, what to retrieve). An agent has everything needed to call it correctly without external context.

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?

Schema coverage is 0% and the schema only has minLength. The description compensates by stating the trainId is opaque and must come from search_trains, not constructed manually. This adds crucial semantic meaning that the raw schema lacks.

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 clearly states the verb ('retrieve') and the specific resource ('that service and its ordered stops'), and explicitly ties it to the opaque trainId from search_trains. This distinguishes it from sibling tools like search_trains or compare_trains without ambiguity.

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?

It gives explicit usage context: use with the opaque trainId returned by search_trains, and warns not to construct IDs manually. It doesn't explicitly rule out alternatives, but the instruction is clear enough for an agent to know when to invoke it versus other tools.

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