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

Annotations already declare readOnly/idempotent/non-destructive, so the safety profile is covered. The description adds real behavioral context beyond them: default output is a compact overview plus route IDs and notices, and 'Research is not live availability' warns that data may be stale — a meaningful caveat an agent would otherwise miss.

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?

Four short sentences, front-loaded with purpose, then example, then optional sections, then sibling routing. Nothing is redundant and every sentence carries information the agent acts on.

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 an output schema present and annotations covering safety, the description supplies what remains: default vs optional sections, data-freshness caveat, and alternative tools. The one gap is not explaining how to obtain a slug (resolve_peak) beyond 'returned by search'.

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% and the sections enum plus its 'omit for compact overview' default are fully documented in the schema. The description's only addition is a concrete example input, which illustrates the slug format but does not extend meaning beyond the schema.

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?

States a specific verb and resource ('Get compact peak facts and route IDs') and immediately scopes it against siblings by naming get_weather and get_huts. An agent can distinguish this from search_peaks/get_route without opening any 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?

Explicitly routes three alternatives: search for fact questions, get_weather for current weather, get_huts for booking info — a genuine when-to-use/when-not set. It omits the resolve_peak vs get_peak distinction, even though resolve_peak is the likely source of the required slug, leaving one sibling relationship to inference.

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