Open URL / risk brief

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

Annotations already establish readOnly/openWorld/idempotent behavior, and the description adds meaningful context beyond that: the 0–100 score direction, the HTTP 402 failure mode with payment/auth guidance, and endpoint selection behavior. No contradiction exists between the annotations and the description.

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 dense but every sentence earns its place: purpose, score semantics, error/auth, routing, and workflow ordering. It front-loads the core purpose and keeps all operational details in a tight sequence with no filler.

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 there is no output schema, the description does enough by mentioning the risk score, page_risk/whois/page categories, and the 402 failure mode. It lacks an explicit response shape, but the risk-brief nature and score range give an agent sufficient context to invoke the tool and interpret the core result.

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 schema already describes q and type, so the baseline is 3. The description adds real value by mapping type values to endpoints: 'For type=url calls /v1/open?q=; for address|token keeps GET /v1/brief?type=&q=', and it clarifies that q is the queried value. This goes slightly beyond the schema without replacing 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?

The description states a specific verb-resource mapping: 'Maps to GET /v1/open for URL checks (page_risk, whois, page)' and clarifies the broader role as a risk brief. It also disambiguates from domain.* siblings by instructing 'Call first for wrap-before-click; then domain.whois / domain.dns / domain.tls', making the tool's position in the workflow clear.

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?

It gives explicit when-to-use guidance: 'Call first for wrap-before-click' and explains the ordering against domain.whois/dns/tls. It also provides conditional routing for type=url vs address|token, telling the agent exactly which endpoint pattern applies and noting the 402 unpaid case with preferred auth headers.

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