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

Annotations already establish read-only, idempotent, open-world, and non-destructive behavior. The description adds meaningful context by revealing that the output contains both normals and a departure-from-normal block, and that the comparison uses the current forecast against a decadal baseline. This goes beyond the structured annotations without contradicting them.

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 description is two sentences plus a concrete example, with no filler. The core behavior is front-loaded and the example reinforces the output form efficiently.

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 6 parameters, no output schema, and no parameter descriptions in the schema, the description is not complete enough for an agent to invoke this correctly in all cases. It omits how to choose between lat/lon and zip_code, how years affects the normals, and what the exact output shape looks like.

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%, so the description must carry parameter meaning, but it only hints at horizon_days ('next N days') and years ('decadal'). It does not clarify location selection (lat/lon vs. zip_code), units, or the exact role of the years parameter beyond the vague 'decadal' clue.

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 specific resource and computation: same-window decadal climate normals for the next N days plus a departure-from-normal comparison. It also gives a concrete example ('This week is 11°F above normal.'), making the tool's purpose unmistakable and distinguishing it from raw forecast or historical tools.

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?

The description implies the tool is for comparing a forecast to a climate baseline, but it does not explicitly say when to use this tool versus alternatives like weather_forecast, weather_historical, or weather_compare. The intended use case is clear but not contrasted with siblings.

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