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

Annotations already establish readOnlyHint=true and destructiveHint=false, so safety is covered. The description adds real value beyond that by disclosing the returned metrics and the ordering behavior (least reliable first), which compensates for the absent output schema; it omits pagination or rate-limit context.

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?

Three sentences, front-loaded with the trigger and immediately followed by the return payload and prerequisite; no filler or repetition of the title.

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?

For a two-parameter read tool with no output schema, the description covers the trigger, the metrics returned, sort order, and the park ID prerequisite, which is enough to invoke it correctly. Minor gaps remain around result volume or whether a single park's full ride list is returned by default.

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 park_id documented as the canonical key (magic-kingdom accepted) and ride_id as an optional single-ride filter, so the schema carries the semantics. The description only reinforces the park ID prerequisite and adds no syntax or format detail beyond the schema, matching the baseline 3.

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?

Specific verb+resource with scope: it returns 30-day uptime, outages per day, and average/longest outage, sorted least-reliable first. It clearly distinguishes itself from siblings like parky_get_waits and parky_get_ride_facts by naming the reliability domain and the user question it answers.

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?

Opens with an explicit trigger ('when a visitor asks how often a ride breaks down or which rides are least reliable') and states a prerequisite ('Resolve the park ID first'). It does not explicitly name a competing sibling tool or a when-not-to-use condition, so it stops short of a 5.

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