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

The description discloses that it returns up to 5 AI-validated routes and allows optional distance filtering, providing some behavioral context. However, it does not mention the behavior of the prefer_gold parameter (e.g., default filtering to gold tier) or clarify that the tool has no side effects. Since no annotations are present, the description carries the full burden, leaving some behavioral aspects ambiguous.

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, consisting of two sentences. The first sentence states the primary purpose and return characteristics, while the second gives practical usage examples. Every sentence adds value without redundancy, and the most critical information is 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?

For a find tool with no output schema, the description adequately conveys the purpose, return count, and filtering criteria. However, it could mention edge cases (e.g., no routes found) or clarify that it returns route summaries rather than full details. The presence of sibling get_route_details for details mitigates the omission, making the description sufficiently 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 input schema already provides detailed descriptions for all three parameters (100% coverage). The description adds context about matching the city and optional target distance, but does not enhance understanding of prefer_gold beyond the schema's own description. With high schema coverage, a baseline score of 3 is appropriate.

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 function with a specific verb ('find') and resource ('existing heart-shaped running route in a given city'), distinguishes it from sibling generate_heart_route by specifying 'existing' and 'AI-validated'. The return limit of 5 routes is also mentioned, making the purpose unambiguous.

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 provides explicit usage guidance with concrete examples ('Use this when a user mentions a city and wants a heart route') and realistic user requests. It does not explicitly state when not to use it or compare with alternatives, but the context is clear enough to guide selection.

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