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

Goes well beyond the readOnlyHint/openWorldHint annotations: discloses that scanning is passive and possibly stale, explains the seen=false/known=false return for missing records and warns that is not proof of closure. Also discloses the pricing model ($0.002 USDC via x402, failed calls free), which is critical for an agent deciding whether to call.

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, front-loaded with what it does, followed by the staleness caveat and the false-negative warning, then pricing. Every sentence carries decision-relevant information with no padding.

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 single-parameter read tool with an output schema and annotations, the description covers the remaining gaps: passive data caveat, the ambiguous seen=false/known=false result, and the cost model. Nothing an agent needs to invoke or interpret it 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?

Only one parameter and schema coverage is 100%, so the schema already documents the IPv4 requirement with an example. The description restates that it operates on an IPv4 address but adds no format, validation, or edge-case detail beyond the schema. Baseline 3 applies.

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 ('Checks') and resource ('Shodan's passive scan records for TCP port 3389 (RDP) on an IPv4 address'). Explicitly contrasts itself with a live test, which separates it from siblings like security_open_port_scanner and security_shodan_host_summary. An agent can tell what this does 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?

Clearly frames the usage context: passive records only, not a live test, records can be days old. This tells the agent when the result is appropriate. It stops short of naming the alternative tool to use when a live check is needed, leaving that inference to the agent.

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