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

Annotations already declare this a safe, idempotent read, so the description does not need to restate safety. It does add genuine context beyond the annotations: the exact field set returned and the conditional caveat that search volume is only present after it has been fetched, which prevents the agent misreading missing values as errors.

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?

One dense sentence with zero filler, front-loading what is listed and then qualifying it. Nothing is repeated from the name or schema.

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 no output schema, the description correctly carries the return-value burden by naming the fields. Pagination is covered by the schema's cursor/limit docs. Only the ordering of results and what the status/tag values mean are left unspecified.

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 coverage is 100% – asin, limit, and cursor are all documented in the schema, including the default page size and the 'omit for first page' cursor rule. The description adds no parameter-level meaning beyond confirming that results are scoped to an ASIN, so 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 states the resource (tracked search phrases for an ASIN) and enumerates the payload (latest position, page, deltas, status, tag, search volume), so the agent knows exactly what comes back. It does not, however, contrast itself with get_rank_history, the sibling most likely to be confused with it.

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?

No when-to-use or when-not-to-use guidance is given, and no alternative is named. The phrase 'when it has been fetched' hints that some fields may be null depending on data state, but that is not framed as a usage condition.

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