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

Annotations already declare readOnlyHint, idempotentHint and openWorldHint=false, so the safety profile is fully covered structurally. The description adds that the payload is a fixed set of 12 facts, but says nothing about caching, freshness, or whether the content varies by anything other than language. With annotations carrying the safety burden, a 3 is appropriate.

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, no redundancy. The content inventory is front-loaded and the routing instruction ('Use first') is placed last, which is the right ordering for an agent scanning for a decision rule.

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 usefully enumerates the topics returned (what it is, price, safety, languages, audience), giving the agent a sense of the return payload. The only gap is that the relationship to the more specific sibling fact-tools is left implicit.

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% for the single 'lang' parameter, including a complete 21-value enum and a default note, so the schema already does the work. The description never mentions the language parameter or how language affects the returned facts, adding nothing beyond the schema; baseline 3 applies.

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 concrete resource ('the 12 key facts about Veliane') and enumerates the covered topics (what it is, price, safety, languages, audience), so the agent knows exactly what comes back. It is clearly the overview entry point relative to narrower siblings like get_veliane_price, though it does not name any specific sibling to contrast against.

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?

'Use first for any "what is Veliane" question' gives an explicit trigger condition and an implicit ordering rule (this before the narrower fact tools). What is missing is an exclusion: it never says to skip this when the user asks about a single attribute such as price or names.

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