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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint and destructiveHint=false, so the safety profile is covered structurally. The description adds the useful 'free public API' note, implying no auth and possible rate limits, but does not state whether the chain is truncated on loops, a max-hop limit, or how failures are surfaced. Given the lower bar set by annotations, this is adequate but thin.

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 compact sentences with no filler; the API-availability note leads and the purpose follows. Slight reordering could front-load the action verb, but nothing is wasted.

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?

With a single required parameter, an output schema, and rich annotations, the description covers what the tool does and roughly what it returns. The remaining gap is redirect-specific edge behavior (loop handling, hop limits), which matters for a chain-following tool but is arguably a schema/output concern.

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 exists with 100% schema description coverage ('Starting URL.'), so the schema carries the semantics. The description adds nothing about URL format expectations, trailing slash behavior, or whether non-HTTP schemes are accepted, so baseline 3 applies.

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 ('follow a URL's redirect chain') and enumerates the return contents (status code, response time, final destination), which clearly separates it from lookup-oriented siblings like tools_dns_record_lookup or tools_whois_lookup. It does not name or contrast itself against the closest neighbor, tools_website_status_checker, so an agent must infer the boundary.

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?

There is no statement of when to use this tool rather than a sibling, no prerequisites, and no exclusions. 'Free public API' hints at accessibility but says nothing about selection between this and tools_website_status_checker or tools_domain_connect_checker, so usage must be inferred from the purpose sentence alone.

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