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

Annotations already flag read-only and open-world behavior, while the description adds meaningful context: the answer comes from the skill's own server-side code, unsupported asks are refused, times use the server's UTC clock, and the result links to a card. The promotional "proven" framing and lack of error or rate-limit detail keep it from being fully transparent.

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 opening identifies the skill, but much of the text is promotional evidence and rating language ("one of the proven skills with the most evidence... never from how it describes itself") that does not help an agent invoke the tool. Useful behavioral details are present but buried among this noise.

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 simple read-only skill query, the description covers accepted ask examples, refusal behavior, server-side execution, and where the result card lives. Output details remain thin, but the input schema is rich and no output schema exists, so it is largely sufficient for correct invocation.

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 100%, so both ask and response_type are documented in the schema, including the enum and an example ask. The description reinforces the ask format with examples but adds no extra semantics for response_type or constraints beyond the 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?

The description names the specific skill and gives concrete distance examples such as "distance from london to paris", so the agent can tell it handles distance queries. It does not explicitly distinguish itself from the sibling drive_time tool, leaving a plausible ambiguity between distance and travel-time asks.

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 examples imply the kind of ask the tool accepts, and the description notes that unsupported asks are refused rather than guessed. However, it never says when to choose this over drive_time or other location-oriented siblings, nor does it state exclusions or prerequisites.

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