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

Annotations already declare readOnly/idempotent/non-destructive, yet the description still adds real behavioral context beyond them: the minute-level external polling, the meaning of 'degraded' (visits taken but counted late, none lost), the meaning of 'stale true' (checker may have stopped), and that all times are UTC. It even states a safety property — it reads nothing of any site.

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?

Purpose is front-loaded and every clause carries information — services covered, trigger, degraded/stale definitions, UTC. The middle sentences are long and clause-stacked, which slightly hurts scannability, but there is 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?

With no output schema, the description must describe the return shape, and it does: per-service and per-location status, problem days in the last 90, last changes and incidents. Combined with the semantic definitions of degraded and stale, an agent has everything needed to call and interpret the result.

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?

The tool takes zero parameters, so the schema carries no burden and the baseline is 4. The description usefully clarifies that all returned times are UTC, which is the only parameter-adjacent semantics that could be ambiguous.

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 resource and scope: fivebar's own status page, checked externally every minute, covering each service (visitor counting, dashboard/API, DNS) and each visit-collection location. It also implicitly separates itself from the analytics siblings by stating 'it reads nothing of any site.' An agent can distinguish this from get_overview or get_site_summary without opening the schema.

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?

It gives an explicit trigger condition: 'Call it when figures look low or missing for a time,' and explains the diagnostic reasoning (a dip may be fivebar's, not the site's). It does not name sibling tools to use instead, but the trigger is concrete enough that no exclusion list is needed.

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