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

Annotations already declare readOnly/idempotent/non-destructive, but the description adds substantial context beyond them: includes are processed before checking, forms must post to /_form/<name>, dead addresses are drawn from the last 30 days of visitor traffic, and external links are out of scope. That is exactly the kind of hidden behavior an agent needs to interpret 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?

The verb and scope are front-loaded, the checklist of failure modes follows, and the closing sentence carries both the usage trigger and the exclusion. It is dense but every clause earns its place; nothing is padded.

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 diagnostic, the description covers scope, triggers, and exclusions thoroughly. The only minor gap is that it doesn't state what the result looks like (a list of issues vs. a pass/fail), though with no output schema that is a small omission.

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?

There is one required parameter, `site`, and the schema already documents it at 100% coverage ("The site name."). The description's phrase "a whole Pagehaus site" adds a little framing but no syntax or naming details beyond the schema, so the 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 (checks) and a precisely scoped resource (a whole Pagehaus site as visitors see it), then enumerates exactly what is examined: broken links/images, failing includes, undeliverable forms, missing index.html, and recently-hit dead addresses. This is far more specific than its sibling check_domain, which is about domains, not site content.

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?

"Use it after making changes" gives a clear trigger for invocation, and "Links to other websites aren't checked" draws a scope boundary. It stops short of naming check_domain or other alternatives explicitly, so it's clear context rather than full when/when-not routing.

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