Train routes in a country

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

Beyond annotations, description reveals sorting by renown, inclusion of hub URL, and error behavior for unrecognized countries. No contradictions.

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?

Three focused sentences: output description, error handling, and usage guidance. No fluff, front-loaded with key information.

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 single parameter, high schema coverage, and no output schema, description adequately explains output structure and error behavior, and directs to alternatives.

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?

Input schema covers 100% of parameters with detailed description. Description adds error handling context for unrecognized country, going slightly beyond schema.

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?

Description explicitly states it returns atlas routes crossing a country, sorted by renown, plus hub URL, and error for unrecognized country. Clearly distinguishes from siblings like search_routes and night_trains.

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?

Provides explicit guidance: use for 'trains in X' questions, and recommends search_routes for combined filters and night_trains for sleepers only.

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