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

No annotations exist, so the description carries the full load and does well: it discloses SSRF guarding, the fact that it follows Location hops, that it returns final_url plus the hop chain, and that no page body is fetched. It does not state a maximum hop count, timeout, or failure behavior when a redirect chain breaks, leaving some operational gaps.

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 core behavior, output shape, scope disclaimer, example, price and alternatives are all packed into a few tight clauses with the most important information first. The trailing related-endpoint list with prices is the only padding, and even that serves routing.

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 tool with no output schema, the description supplies the return fields (final_url + chain), the no-body constraint, the security posture and the explicit non-goal. Nothing an agent needs 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?

Only one parameter with 0% schema description coverage, so the description must compensate. The concrete example {url:"https://example.com"} confirms the parameter is a fully-qualified URL string, which is the key detail an agent needs; it adds nothing about scheme restrictions or normalization.

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 ('Unwrap URL redirects / short links: follow Location hops') and scopes the output ('return final_url + chain (no body)'). An agent can distinguish it from read_url and page_meta on the sibling list without opening any 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?

Explicitly bounds scope with 'Not a malware verdict' and names four alternative endpoints (/read, /meta, /check, /links) with prices, which implicitly routes an agent to the right tool. It stops short of an explicit when-to-use statement for these alternatives, so the routing is inferred rather than stated.

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