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

Annotations only declare readOnlyHint=true, so the description carries the rest — and it does disclose meaningful behavioral detail: it returns a plain-language verdict, distinguishes real issues from likely false positives, shows latest run and schedule per check, setup state, suggested-but-missing checks, and account run usage. It stops short of stating cost, latency, or scope limits, so 4 rather than 5.

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?

A single sentence, front-loaded with the core concept ('plain-language health verdict for a site') followed by a comma-separated inventory of contents. Every item listed is informative rather than filler, though the tail-end enumeration is dense enough to read as a checklist.

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 bears the burden of explaining returns, and it does so thoroughly — verdict, issues with false-positive framing, per-check run/schedule, setup state, recommendations, and usage. It omits any mention of response size or pagination, which is the only notable gap for a composite overview 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?

There is a single parameter (siteId) with 100% schema coverage, though the schema description itself is just 'The site id'. Per the baseline for high schema coverage, a 3 is appropriate; the description adds no scoping or format detail about the id beyond what the schema already provides.

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 names a specific deliverable — a "plain-language health verdict for a site" — and enumerates its contents (issues, checks with runs/schedules, setup state, recommended checks, run usage). That is far more precise than a restated title. It does not name siblings like list_checks or list_runs, so the agent must infer the differentiation, which keeps it at 4 rather than 5.

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 aggregate nature of the output (health verdict, recommended checks, account run usage) suggests it is the entry-point summary versus per-entity siblings such as list_checks, list_runs, and get_run. There is no explicit 'use this when... / use X instead when...' guidance or prerequisite note.

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