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

With no annotations, the description carries the full burden, and it discloses meaningful traits: tier-gated horizons (free: 7 days), section availability by tier (minutely 'higher tiers', alerts 'startup tier and above'), timezone/unit defaults, and the flattened table output shape. It omits auth requirements, rate limits, and error behavior, but the tier and output disclosures go well beyond the schema.

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 purpose and capacity in the first sentence, then organized into labeled sections for parameters and output. It is dense but each sentence carries information; the output paragraph is somewhat long given no output schema exists to carry that load.

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 an 8-parameter tool with no annotations and no output schema, the description covers the essential gaps: forecast horizons per tier, section semantics, output table structure with flattened column naming, and unit/timezone behavior. An agent has enough to call it correctly without opening the schema.

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% at the top level, so the description must compensate, and it largely does: it enumerates valid `sections` values, explains that hourly is trimmed to `hours` and daily to `days`, names example `variables`, and defines `timezone` and `units` defaults. It leaves `language` and the `locations` array limits/shape unexplained, so it falls short of full coverage.

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+resource ('Weather forecast') with a stated capacity limit ('up to 20 locations in one call'), which clearly separates it from get_weather_history, get_air_quality, and get_solar_production. It does not address the overlap with get_alerts, even though its own 'alerts' section covers the same data, leaving that sibling distinction unstated.

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 implied rather than stated: it recommends using `variables` 'when querying many locations' and notes tier requirements per section, which is useful operational guidance. However, it never says when to prefer this tool over get_alerts, get_weather_history, or how to obtain a place_id before calling (search_places), so the routing decision is left to inference.

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