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

Annotations already declare readOnly, idempotent, non-destructive, closed-world, so the safety profile needs no restating. The description adds ordering behavior (newest first), the full item payload shape (id, target_domain, status, sample_mode, page counts, client_id, diagnostic_report_id, dates), and the empty-result semantics, all beyond what annotations provide.

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 core purpose is front-loaded in the first clause and the single paragraph is dense with signal rather than filler. It runs long because it covers the item shape and status vocabulary, which is necessary given there is no output schema, but the field enumeration reads as a run-on list and could be structured more scannably.

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 four optional params, no output schema, and simple read-only semantics, the description supplies exactly what is missing elsewhere: what a scan is, what each returned item contains, what the statuses mean, and how to interpret an empty page. Nothing an agent needs in order to call it correctly and interpret the result is absent.

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 50%, with limit and cursor already documented in the schema. The description compensates by explaining what each status value means in the domain ('the first three are the free sitemap import and page review'), which directly informs filtering, though client_id is still only named, not explained, and cursor paging is left entirely to the schema.

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?

The description opens with a specific verb and resource ('Lists the Crawlability Scans in the connected account, newest first') and then defines what a Crawlability Scan actually is, so an agent knows the object being listed. It does not explicitly name the singular sibling get_crawlability_scan as the alternative for a single scan, relying on the plural verb to imply the distinction.

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?

It states the available filters ('client_id and status') and warns that an empty page means no match for these filters rather than an empty account, which is genuinely useful usage context. However, it never says when to reach for this list versus get_crawlability_scan, list_diagnostics, or the other list_* siblings, and gives no guidance on iterating with the cursor.

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