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

Annotations already declare readOnlyHint, idempotentHint, and non-destructive behavior. The description adds useful context beyond these: the tool is free and there are paid full feeds for humans, which clarifies the cost model and audience without contradicting any annotation.

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?

Two concise sentences front-load the primary purpose and add relevant cost/link information without wasted words. Every sentence contributes useful detail.

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 tool is a simple list with no parameters and no output schema, the description sufficiently defines its scope (cities, pricing, payment details) and provides cost context. The external link for paid feeds is a practical addition.

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?

With zero parameters, the schema provides no property semantics. The description compensates by stating the output includes pricing and payment details, giving meaning to what the returned list covers, which exceeds the baseline for no parameters.

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 a specific action ('List') and resource ('cities covered by the Permit Intelligence API'), adding valuable detail about pricing and payment information. It distinguishes this tool from siblings by explicitly naming the unique scope of covered cities.

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 notes it is 'Free' and points to paid human feeds on the pricing page, implying the API tool is for free programmatic access. However, it does not explicitly state when to use this tool versus alternatives among sibling tools, leaving usage guidance only implicit.

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