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

Annotations already establish readOnly/idempotent/non-destructive, and the description reinforces this plus adds genuinely new behavior: results may be reused free, ordering is newest-first, and re-running with identical args hits a cache. It does not disclose cache staleness/expiry rules, which is the one behavior an agent would want to know before relying on reuse.

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?

Front-loaded with the core purpose, then the cost-saving rationale. Slightly long because the reuse mechanism is explained twice ('ALREADY run' and 'cart that tool again'), but each sentence carries useful information.

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 an output schema present, return-field detail is unnecessary, and the description covers what is listed and why. The only gap is the undocumented 'limit' parameter, which is minor for a one-parameter read-only tool.

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 single 'limit' parameter has 0% schema description coverage and is never mentioned in the description, so its meaning (max history entries returned, default 20) must be inferred. The 'newest first' note gives partial ordering context but nothing about the parameter itself.

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 concrete verb ('Lists') and resource ('SEO/AEO add-on queries this account has ALREADY run'), and enumerates what each entry contains (tool, query, time, reusability). This is clearly distinguishable from the many seo_* analysis siblings, which run new work rather than reporting past runs.

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?

Explicitly says to call this BEFORE running an expensive SEO tool and explains the exact follow-up action: re-call the same tool with the same arguments to get the cached result at zero credits. It names both the when and the alternative, which is unusually strong routing guidance.

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