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

Annotations already declare readOnlyHint and openWorldHint, so safety is covered; the description earns credit for adding genuine behavioral context: it is free, scoped to public websites only, takes 20-90 seconds, and returns a fix prompt plus report link without a full report. A straightforward good addition over the structured data.

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?

One dense sentence that front-loads what the tool does and then lists outputs and the latency expectation. Every clause earns its place, 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?

With no output schema, the description carries the return-value burden and does so: it names the health score, issue categories, fix prompt, and report link. Latency is disclosed, and the read-only safety profile is covered by annotations. Nothing essential is missing for correct invocation.

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 100% schema description coverage, so baseline is 3; the description adds the meaningful constraint that the target must be a public website (implying non-public or internal URLs are out of scope), which the schema does not encode. Modest but real added value.

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 ('Runs a free NexusBro audit of a public website') and enumerates the deliverables (health score, top issues across SEO/speed/broken pages/accessibility, fix prompt, report link). This is unambiguous and clearly distinct from the informational sibling about_nexusbro.

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?

Usage is implied by the name and description (audit a public site) plus the latency note ('20 to 90 seconds'), but there is no explicit when-to-use vs when-not guidance and no alternative named against the about_nexusbro sibling. Minimum viable routing context, nothing more.

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