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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description adds genuine behavioral context beyond that: the upstream data source (MET Norway model), the exact field set returned, the forecast horizons (24h hourly, 10 days daily), and the obligation to cite the returned URL. It does not disclose freshness/caching or rate-limit behaviour, so it stops short of a 5.

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?

Front-loaded with the core purpose, then the field list, then the forecast horizons, then the citation requirement — a sensible ordering with no filler. The field enumeration is long, but each item maps to a real returned value, so only minor trimming would be possible.

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 responsibly enumerates return content (temperature, heat index, wind, humidity, cloud, next-hour precipitation, sunrise/sunset, hourly and daily outlooks), which is exactly what an agent needs to plan a response. It is incomplete only in the routing dimension — nothing tells the agent when this beats get_observed_weather or get_climate.

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 100% and both optional lat/lon parameters carry their own bounds and defaults in the schema. The description adds nothing about coordinates — not even that the tool is constrained to Phuket — so the baseline 3 applies rather than any upside.

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 ('Текущая погода на Пхукете по модели MET Norway') and enumerates the returned fields precisely, so an agent knows exactly what it gets. It does not, however, distinguish itself from close siblings like get_observed_weather or get_climate, leaving the agent to guess which weather tool is authoritative for a given request.

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?

Usage is only implied: the wording 'сейчас / current weather' signals a real-time snapshot, and the closing instruction 'cite the returned URL' is a concrete usage requirement. There is no explicit when-to-use or when-not-to-use guidance, and no mention of get_observed_weather or get_climate as alternatives, which is a real gap given the crowded weather-tool neighbourhood.

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