Investigate a link (network)

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

With no annotations, the description carries the full burden and does so: it discloses the outbound network side effect, the SSRF-style guard that refuses private, loopback and link-local targets, and the crucial safety boundary that it reads metadata only and does not execute page content or act as a sandbox. These are exactly the traits an agent needs before calling an outward-facing fetch.

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 with zero padding; the capability and its returned fields come first, followed by the scoping/safety constraints. Every clause earns its place.

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?

There is no output schema, and the description compensates by naming the returned fields (redirect chain, final URL, title, TLS, RDAP age, flags). Combined with the stated safety boundaries and refusal behavior, an agent has everything needed to invoke it correctly and interpret the 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%, so both parameters are already documented, warranting the baseline 3. The description does reinforce that the target must be a public HTTP(S) URL, but it never mentions that the 'rdap' lookup can be disabled — it only lists RDAP domain age as a return field, leaving the toggle's effect to the schema.

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 gives a specific verb and resource ('Fetch public HTTP(S) metadata for one link') and then enumerates exactly what comes back: redirect chain, final URL, title, TLS issuer/version, RDAP age, and heuristic flags. It explicitly separates itself from the other scamcheck tools by stating it is the ONLY one that touches the network.

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 'ONLY scamcheck tool that touches the network' line tells an agent when this tool is the right pick over check_message, check_number, and extract_entities for a link. The refusal of private/loopback/link-local targets is a clear negative condition. However, it never says when not to use it (e.g., for a bare domain vs a full URL) or how it relates to extract_entities for link discovery.

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