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

Annotations already declare readOnly/openWorld/non-destructive, but the description adds real behavioral context: it lists the redirect codes followed (301/302/307/308), notes loop detection, describes returned fields (final URL, server, response time), and gives a batch limit. That is meaningful disclosure beyond the structured fields.

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?

Front-loaded and short, but the telegraphic fragments repeat the same idea ('HTTP status and redirect chain of a URL... Check URL. HTTP status...') without earning their place. Functional, but not tight or well-structured.

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 no output schema, the description carries the return-value burden and does so by naming status, redirect chain, final URL, server, and response time. It is nearly complete for a single-param read tool; only the batch-vs-single-URL ambiguity leaves a small gap.

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 the schema already documents url and maxRedirects, making 3 the baseline. The description adds a batching note ('up to 20 URLs per call') that is not reflected in the single-`url` schema, which is mildly confusing rather than clarifying.

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+resource (check a URL's HTTP status and redirect chain) and enumerates what it returns. It is distinguishable from link_preview or expand_short_url in intent, but it never explicitly contrasts itself with those siblings, so it stops short of a 5.

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?

'Find broken links fast' implies a use case, and 'POST up to 20 URLs per call' hints at batch sweeps. However, there is no explicit when-to-use/when-not guidance and no named alternative, so usage is only implied.

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