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

Annotations already declare readOnly/openWorld/idempotent, so the safety profile is covered. The description adds genuinely new behavioral context the annotations cannot convey: the data is free, stale by one day, keyed to the America/Chicago calendar day, and not live. It does not describe pagination or response shape, keeping it out of 5 territory.

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?

Three short sentences, front-loaded with the most decision-relevant fact ('Free'), followed by what it returns, the staleness caveat, and the no-input note. Every sentence earns its place with no filler.

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 a 0-param, no-output-schema tool the description covers the essentials: cost, freshness, timezone, and that it is a format-inspection sample. A brief note on the report's contents or size would round it out, but nothing required to invoke it correctly is missing.

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?

The tool takes zero parameters and the description explicitly confirms 'No inputs,' which is exactly the right signal for an empty schema. There is nothing further to disambiguate, so the baseline for a parameterless tool applies.

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 (returns), a specific resource (a sample of the conditions report), and bounds it precisely ('previous calendar day, America/Chicago'). The phrase 'Not live data' implicitly contrasts it with the live-report sibling, so an agent can distinguish it from get_current_conditions without opening either 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?

Gives a clear purpose-condition: use it to 'inspect the report format before paying.' That tells the agent when the tool is appropriate. It does not explicitly name an alternative tool to use instead once the decision to pay is made, so it falls just short of a 5.

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