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

Annotations already declare readOnlyHint, idempotentHint, non-destructive and closed-world, so safety is covered. The description adds the non-obvious default behavior — omitting platform returns all platforms — which the schema does not state anywhere. It stops short of describing what the response contains (links vs. steps), but that is a minor gap against the annotation coverage.

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 with no filler, and the platform default is placed at the end where it is easy to catch. Slightly awkward phrasing ('Where to download Wuai and how to install it') keeps it from being a 5.

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 one-optional-parameter lookup tool with full annotation coverage and no output schema, the definition covers purpose, scope and default behavior. The only real omission is a hint about what is returned (download links, install instructions, or both), which would help an agent decide whether to call it or read the answer from another 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 coverage is 100%, so the baseline is 3; the description earns an extra point by explaining what an omitted platform means (all of them), which the enum property description does not convey. The four enum values are already documented in the schema, so no further credit is due there.

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 verb-ish intent: where to download and how to install Wuai, scoped by platform. It is clearly distinct from siblings like get_pricing or get_faq, though it never explicitly contrasts with them.

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 parenthetical '(all of them when no platform is given)' gives a real usage rule for the optional parameter, which is genuine guidance. However, there is no statement of when to prefer this over sibling tools such as how_to or get_faq, so the when-to-use framing is only implied.

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