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

Goes well beyond the readOnlyHint/openWorldHint annotations: it discloses the data source (Shodan pre-collected passive scans), staleness risk, that no active probing occurs, the pricing ($0.002 USDC per successful call), the payment rails (x402 on Base, Solana, Arc), and that failed calls are free. That is exactly the cost/behavior context an agent needs before calling.

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?

Three tight sentences: what it checks first, then the key caveat, then cost. No filler, and the most decision-relevant information (passive, no community string) 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?

Return values are covered by the output schema, and the description supplies the remaining essentials: data provenance, staleness, scope limits, and billing behavior. Nothing an agent needs in order to call this correctly is missing.

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% and the single 'ip' parameter already documents the IPv4 format with an example, so the schema does the heavy lifting. The description only reinforces 'IPv4 address' without adding format, validation, or edge-case detail beyond it.

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?

States a specific verb and resource: reports whether Shodan's passive scan data shows UDP/161 SNMP open on an IPv4 address. The passive-data framing implicitly separates it from active siblings like security_open_port_scanner or security_censys_exposure, though no sibling is named explicitly.

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?

Gives clear usage context plus an explicit exclusion: no community string is tried, so default/public community access is not tested, and the data may be stale. It stops short of naming the alternative tool an agent should pick when it needs a live probe or full host picture.

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