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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint and destructiveHint=false, so the safety profile is covered. The description adds one genuine constraint, the free forecast window limitation, and reinforces 'Informational only', but otherwise restates return contents and the elevation default already present in 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?

The lead sentence front-loads the return payload and scope, and the second sentence handles the inputs efficiently. It is dense but every clause carries content; the trailing 'Informational only.' fragment is slightly redundant given readOnlyHint but not wasteful.

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, return-field detail need not be repeated, and annotations cover safety and idempotency. The description supplies the key operative constraints (free forecast window, single day, optional elevation band), leaving only sibling-differentiation guidance as a gap.

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%, so all five parameters are already documented in the schema, including the elevation_band enum and its default. The description adds only marginal meaning (e.g. the date must be from visible/free-window days), which justifies the baseline 3 rather than more.

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 names a specific verb and resource (returns two-hourly temperature, wind speed, wind direction) and pins down the source (weather-by-elevation grid in the forecast page's hourly view) and scope (one day). It is clearly distinct from a generic conditions lookup, though it never explicitly names sibling tools like get_route_conditions or get_objective_conditions to draw the boundary.

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 through the input constraints ('a date from the route's visible days', 'one day in the free forecast window'), which tells the agent when a call will succeed. However, there is no explicit when-to-use guidance versus alternatives such as get_route_conditions or get_objective_conditions, and no exclusions.

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