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

Annotations already declare destructiveHint=true, idempotentHint=false, and readOnlyHint=false, lowering the bar. The description nonetheless adds non-obvious behavior: duplicate terms create two rows, and keywords lacking a country are skipped by the weekly rank check. It stops short of permissions or rate-limit context.

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 tight sentences, front-loaded with the use case, then return/side-effect facts, then the exclusion. Every sentence carries distinct information 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?

With annotations covering the safety profile and an output schema covering the return value, the description supplies the remaining essentials: trigger condition, duplicate behavior, and a sibling exclusion. Only minor gaps (auth or quota expectations) remain.

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 appId, country, language, and searchTerms with examples. The description only reinforces the country-skip rule that the schema already states, adding little new semantic value; baseline 3 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?

The description names a specific verb and resource ('start tracking a keyword for their app in a given language and country') and explicitly distinguishes from a sibling action ('Not for a one-off rank lookup', i.e. get_keyword_rank). An agent can route without opening the 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?

It states the trigger condition ('when someone asks to start tracking a keyword'), names the alternative tool's domain implicitly, and gives a negative case ('Not for a one-off rank lookup'). Both when-to-use and when-not-to-use are present.

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