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

With no annotations, the description carries the full burden; it does disclose two real behavioral traits — the 10-hop cap and a cost of 1 credit per call — plus the shape of what it reports. It does not cover error behavior when the hop limit is exceeded, timeout/pagination behavior, or whether it needs any auth, but for a simple read tool the disclosures it makes are meaningful.

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 short sentences, front-loaded with the action and output, then the use case, then the cost. Every sentence supplies distinct information with no filler or repetition of the tool name.

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 one-parameter read-only tool with no output schema and no annotations, the description covers purpose, output content, hop limit, and cost — enough for an agent to call it correctly. Minor gaps remain around failure modes (e.g. non-redirecting URL, hop overflow) that the description leaves unstated.

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 0%, so the description must compensate for the single url parameter. 'Follow a URL's redirects' does convey that the parameter is the URL whose chain is traversed, but adds no detail on accepted forms, scheme handling, or normalization beyond the schema's format: uri.

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 uses a specific verb and resource ('Follow a URL's redirects hop by hop and report each status code and location'), and even bounds the scope with 'up to 10 hops'. It is clearly a redirect-tracing tool rather than a generic URL checker like check_urls, though it never names a sibling to make the contrast explicit.

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?

'Useful for tracing shortened or tracking links' gives one concrete use context, which is more than nothing but far short of explicit when-to-use/when-not guidance. No alternatives (e.g. check_urls, page_metadata) are named, and there is no guidance on when this is the wrong tool.

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