calculate_distance

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

The description discloses the use of Nominatim for geocoding and output in both kilometres and miles, providing reasonable behavioral context without annotations. It does not discuss failure modes or rate limits.

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 concise, front-loaded with the core purpose, and structured with a brief method explanation and parameter list. No redundant sentences.

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 output schema exists, the description still covers inputs, method, and outputs (km and miles) sufficiently for a simple two-parameter tool.

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 description adds meaning beyond the schema by providing examples (e.g., 'London', 'Paris') and clarifying that parameters are city names, compensating for 0% schema coverage.

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 specifies 'Calculate the great-circle (Haversine) distance between two cities' with geocoding via Nominatim, clearly differentiating from sibling tools like distance_2d that might operate on coordinates.

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 usage for city names but does not explicitly state when to use this tool versus alternatives or mention any exclusions (e.g., if coordinates are available).

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