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

With no annotations, the description carries the full behavioral burden and does it well: it enumerates the external sources consulted (Astur, Shodan InternetDB, GreyNoise, Spamhaus/FireHOL, Feodo, Tor, DShield), discloses that deep is slower with more calls, and warns that the deep signals can only WORSEN the overall grade, never lift it. It stops short of stating auth needs, rate limits, or timeout behavior for the slow multi-call path, so it is not fully complete.

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 purpose and the routing rule are front-loaded, and the long enumeration of report contents is informative rather than filler for an aggregation tool. It is dense and the output enumeration is heavy, but each clause corresponds to a real returned signal, so little is wasted.

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 no annotations and no output schema, the description enumerates the returned report components and explains the depth flag, so an agent knows what it will get back. It omits response format/structure and error or timeout handling for the heavier deep sweep, which leaves a small gap for a multi-call aggregation 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?

Schema description coverage is 100%, so the baseline is 3, but the description adds real meaning beyond the schema by explaining the consequence of depth='deep' (adds RPKI, disclosure contacts, subdomain takeover, IP reputation verdict, TLS posture, CVE ranking; more calls, slower) and its effect on the grade. This goes beyond the terse enum-like schema wording.

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 ('Run a full reconnaissance sweep of a domain or URL') and then enumerates the exact dimensions of the correlated report (web-security grade, SPF/DMARC, nameservers, MX, registrar, CT subdomains, IP exposure, reputation, roll-up grade). It explicitly distinguishes itself from the granular siblings at the end, so an agent can tell it apart from scan_site or spf_check without opening a 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?

Gives explicit routing guidance: 'Use this for broad investigate X requests; use the granular tools (scan_site, spf_check, …) for specific questions.' It also states the condition that selects the expensive path ('Pass depth="deep" to also run the heavier OSINT (more calls, slower)'), covering both when-to-use and the alternative selection rule.

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