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

Annotations already cover the safety profile (readOnlyHint=true, destructiveHint=false), and the description adds real conditional behavior: runsNow distinguishes manual vs post-verification runs before ownership proof, and withWordPressPlugin is populated only for sites added as 'other'. This is useful state-dependent context not present in the annotations.

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?

Two information-dense sentences with little waste; the field catalog comes first and the conditional edge cases follow. The opening is a noun phrase rather than a verb-led statement, which slightly weakens front-loading, but overall it is efficient.

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 must carry the return-value burden, and it does enumerate the key fields (key, what it catches, plan allowance, recommendation, already-added) plus conditional fields. It omits concrete key values and return shape, but is largely complete for a single-parameter read tool.

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 description coverage is 100% with a single siteId parameter, so the schema already documents the input. The description alludes to site context (ownership proof, 'other' site type) but adds no syntax or format detail for siteId beyond the schema's 'The site id'.

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 clearly establishes the resource as the set of monitors that can be added to a site, and it names the sibling 'add_checks' indirectly by describing pre-add discovery. It does not restate the verb 'list' explicitly (that lives in the title), but an agent can still distinguish it from get_check or add_checks.

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 rather than stated: the mention of plan allowance, recommendation, and 'already added' flags implies you call this before adding monitors. There is no explicit when-to-use, no exclusion, and no named alternative such as add_checks or get_check, leaving the agent to infer the routing.

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