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

Annotations already cover the safety profile (readOnlyHint, idempotentHint, destructiveHint=false), so the bar is lower; the description adds the useful behavioral fact that this is a static reference with no network access, reinforcing openWorldHint=false. It also enumerates what the explanation contains, which tells the agent the response is substantive rather than a stub.

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 sentence, front-loaded with the verb and resource, then the id provenance, then the contents, then the no-network constraint. 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?

There is no output schema, so the description takes on the burden and discharges it by listing the returned content (metric, pass/fail thresholds, rationale, fix, effort). Combined with a fully documented single enum parameter, nothing needed to call it correctly is missing.

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% with a full enum, so the schema does the heavy lifting. The description still adds meaning by stating the id is 'as returned by scan_website', telling the agent where to obtain a valid value rather than inventing one.

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 (explain) and resource (one Site Check check by id), and names scan_website as the source of valid ids, which separates it from the sibling scanning tool. An agent can tell immediately this is a lookup of static documentation, not a scan.

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?

The description establishes when to use it — after scan_website returns a check id you want explained — and notes it is a static reference with no network access, so it need not be called alongside a live scan. It does not spell out explicit exclusions, but the context is clear.

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