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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety profile is covered. The description adds two real behavioral facts — the builds are 'measured' (empirical, not theoretical) and identifier formats are flexible across locales — but says nothing about data freshness, sample size, or returned structure.

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?

Two sentences, zero filler, with the payload description front-loaded ahead of the input-format note. Every clause earns its place.

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 whose annotations cover the safety profile, the definition is minimally adequate. However, with no output schema and no annotation detail on returns, the agent gets no sense of response shape, and the locale parameter is entirely unexplained — a clear gap rather than a fatal one.

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 description coverage is 0%, so the description must carry the load. It usefully characterizes the required 'champion' parameter as accepting ids, names and aliases across all site locales, which is genuinely beyond the bare 'string' in the schema. It says nothing about the 'locale' parameter's accepted values or its 'en' default, leaving one of two parameters undocumented.

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?

Names a specific verb+resource: it returns 'measured item builds and skill orders' for a champion, which is more concrete than a generic 'get data' claim. It is reasonably distinguishable from get_tier_list and get_top_combos, though it never explicitly contrasts itself with them, so it stops short of a 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?

There is no when-to-use guidance and no named alternative. The only contextual cue is 'for a champion', which tells the agent the input shape but not when this tool beats get_top_combos or get_tier_list, both of which plausibly overlap.

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