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

With no annotations provided, the description carries the full burden of behavioral disclosure. It transparently discloses the payment requirement ($0.01 via x402, USDT on X Layer), the lack of account/signup needed, and the 402 challenge retry mechanism with the PAYMENT-SIGNATURE header. It also clarifies that pitch is free. While it doesn't explicitly assert read-only behavior, the 'scan' verb and lack of mutation language make this a reasonable inference. The key cost and challenge behavior are well covered.

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 structured and front-loaded: the core function is stated first, followed by payment details, then the differentiation from pitch. Each sentence contributes to the agent's understanding—there's no filler. While it's slightly longer than minimal, every sentence adds necessary context (payment, cold start, sibling distinction), so it earns its length.

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 tool with one parameter and no output schema, the description is quite complete. It explains the ranking order, the full universe scan, the payment flow including the 402 challenge and retry, and the relationship with pitch. It lacks an example output format, but the description implies returning area names. Given the complexity of the payment mechanism, it covers the critical operational details an agent needs to successfully call the 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 schema description for the single 'limit' parameter fully explains its function (how many to return, default 5, max 42) with 100% coverage. The tool description does not add any additional semantic meaning about the parameter beyond what the schema already provides. Per the rubric, with high schema coverage, the baseline is 3, and there is no extra value added.

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 verb ('Scan'), the resource ('all 42 Dubai areas'), and the specific output ('return those closest to a top, ranked most-top first'). It also distinguishes itself from siblings by noting it doesn't require a symbol (contrasting with evaluate_symbol) and that the free pitch tool gives counts while this gives names.

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 explicitly contrasts with the free pitch tool ('The free `pitch` tool tells you HOW MANY are at a top right now; this names them'), providing a clear condition for choosing this over pitch. It also positions itself as a cold-start tool, implying evaluate_symbol requires a symbol. However, it doesn't explicitly state when to avoid scan_bottoms or other alternatives, though the name and context make it implicit.

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