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

Annotations only declare readOnlyHint=true, so the description carries the rest: it discloses that results span four distinct problem classes including paused/muted checks, and that it is derived from GET /api/checks. It omits return shape, ordering, or pagination behavior, but adds real context beyond the annotation.

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 and the four problem categories are front-loaded in a single dense sentence, with the data source relegated to a trailing note. Slightly long but every clause adds information; little waste.

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 does the work of telling the agent what comes back by enumerating the problem categories. It stops short of describing the result structure (grouped lists vs. flat), which is a modest gap for a reporting tool, but overall it is sufficient to call correctly.

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%, so the baseline would be 3, but the description frames both parameters conceptually as 'expire within N days' thresholds tied to the SSL/domain expiration checks. That clarifies what each numeric window controls, going slightly beyond the schema's own wording.

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 states a specific verb and scope ('One-call health overview across every check') and enumerates exactly what it surfaces (DOWN checks with duration/error, invalid SSL, expiring certs/domains, paused/muted). This clearly separates it from siblings like updown_list_checks and updown_get_check, which enumerate rather than diagnose.

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 phrase 'one-call health overview' implies this is the aggregate tool to reach for instead of stitching together list/get/metrics calls. It gives clear usage context but never explicitly names an alternative or states when *not* to use it.

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