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

Annotations already declare readOnly, idempotent, openWorld, and non-destructive, so safety is covered. The description adds meaningful behavior beyond that: the 15-hop cap, per-hop status codes, and the cross-domain indicator, which shape how an agent interprets results.

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?

Two tightly packed sentences, front-loaded with what the tool does, followed by the routing advice. Every clause carries information 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?

There is no output schema, and the description compensates by describing what is returned (each hop, status codes, cross-domain flag) plus the hop limit. Given the single-parameter simplicity, this is nearly complete, though it could note error behavior for unreachable URLs.

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% for the single 'url' parameter, so the schema already documents it fully. The description confirms the hop-by-hop intent but adds no format or syntax detail beyond the schema; baseline 3 is appropriate.

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 (follows) and resource (redirect chain) with scope details (up to 15 hops, per-hop status codes, cross-domain flag). It clearly distinguishes itself from siblings like url_reputation and link_metadata by describing the hop-by-hop traversal.

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 characterizes the use case ('short or tracking link') and names a follow-up alternative ('check the final URL with url_reputation'). It does not state when NOT to use it, but the intended context is unambiguous.

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