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

With no annotations, the description carries the full burden and does surface two real behavioral facts: results are historical rather than live, and coverage has gaps on some days. It says nothing about authentication, rate limits, result ordering, or what a response looks like, which leaves the read behavior only partly characterized.

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?

Two compact sentences with the scope constraint front-loaded and no filler. The phrase 'from 2024-11-28' is ambiguous, though — it reads as either the earliest available date or a data vintage, and the reader has to guess.

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 three-parameter read tool with full schema coverage and no output schema, the essentials are present, and the missing-days caveat is valuable. However, the 2024-11-28 anchor is left unexplained and the return content is never characterized, so an agent still lacks a full picture of what to expect.

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 the schema already documents format, defaults, and ranges for date, limit, and country. The description adds only the framing that the day must be in the past, which slightly reinforces the date parameter but goes no further.

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 resource and verb-less but clear operation: top Google trending searches scoped to one country on a past day. The country scope distinguishes it from get_world_trends by implication, but the description never names that sibling or get_top_trends, so an agent must infer the split.

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?

Implies usage (historical, country-scoped lookups) and warns that some days are missing, which shapes when a caller can rely on it. There is no explicit routing guidance versus the closely named siblings get_top_trends and get_world_trends, so the when-to-use decision remains inferred.

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