12306-MCP

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

No annotations are provided, so the description carries the full burden. It describes the query behavior but lacks details about response format, error handling, rate limits, or authentication requirements. For a tool with no annotation coverage, this is insufficient behavioral disclosure.

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 perfectly concise with two sentences that each earn their place. The first states the core functionality, the second provides usage context. No wasted words, well-structured and front-loaded.

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?

Given the tool's moderate complexity (single parameter lookup), no annotations, and no output schema, the description is adequate but incomplete. It explains when to use the tool and what it does, but lacks details about return values, error cases, or operational constraints that would be needed for full contextual understanding.

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?

With 0% schema description coverage and only one parameter, the description adds significant value by explaining that stationNames should be specific Chinese station names used as departure/arrival locations. This clarifies the parameter's purpose beyond the bare schema, though it doesn't specify format or examples.

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 tool's purpose: querying station_code and station names using specific Chinese station names. It specifies the verb ('query'), resource ('station_code and station names'), and distinguishes from siblings by focusing on exact station names rather than city-based or telecode-based lookups.

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 explicitly states when to use this tool: when users provide specific station names as departure or arrival locations to prepare station_code parameters for other interfaces. It distinguishes from siblings by specifying it's for exact station names, not city-based or telecode-based searches.

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