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

readOnlyHint=true already declares this is a safe read. The description adds useful substance by listing the scan lifecycle states and the score breakdown, which annotations cannot express. However, it says nothing about the case where no scan exists yet (empty result vs error) or about staleness of the 'most recent' scan.

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 tight sentence, front-loaded with the core purpose and then the return contents. The long parenthetical list of sub-scores is dense but each item is informative, so little 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 no output schema, the description usefully substitutes by enumerating statuses, scores, pages crawled, and issue count. Combined with a fully documented single parameter, only the no-scan-yet edge case is missing for a complete picture.

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?

Single parameter with 100% schema description coverage ('Domain id of one of the user's projects, as returned by list_domains'), so the schema already carries full semantics. The description adds nothing about domainId; 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?

Names a specific verb+resource (status and results of the most recent scan of a domain) and enumerates the returned fields, so the agent knows exactly what it gets. It implicitly separates itself from run_scan (this reads, it does not trigger), but never names that sibling.

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 only implied: 'most recent scan' suggests 'poll after starting a scan', but the description never says when to call this versus run_scan, nor what to do while a scan is pending. No exclusions or prerequisites are stated.

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