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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint, covering safety. The description adds valuable behavioral context by specifying the content returned: live bands, limits, privacy guarantees, and taxonomies. It also hints at the static nature by saying 'Call this once,' implying idempotency. While it doesn't describe return format or size, the annotation coverage lowers the burden, and the description meaningfully extends beyond annotations.

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 two concise sentences. The first states exactly what the tool returns, front-loading the core content. The second gives a usage directive. No fluff or redundancy; every clause earns its place.

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 parameterless, read-only tool with no output schema, the description fully equips an agent: it states what data is returned (coverage, limits, privacy, taxonomies) and when to use it (to explain Vicinity and where it works). There is no missing information that would prevent 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?

There are zero parameters, so the schema coverage is trivially 100%. The description does not need to elaborate on parameters. Per the rubric, 0 params gets a baseline of 4, and the description adds nothing contradictory or missing.

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 identifies the tool as returning 'the full coverage list with live bands, plus the published limits, privacy guarantees, section and event-category taxonomies.' It names a specific resource (coverage data) and the content. It also distinguishes itself from siblings like get_city or list_events by focusing on coverage and limits, so an agent can differentiate it without opening the schema.

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?

It provides a clear usage context: 'Call this once if you need to explain what Vicinity is and where it works.' This tells the agent when to invoke it. However, it does not explicitly mention when not to use it or name alternative tools, such as get_city for city-specific details. The guidance is clear but lacks exclusions.

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