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

Annotations already cover the safety profile (readOnly, idempotent, openWorld, non-destructive), so the description correctly spends its words on things annotations cannot express: no API key needed, free tier, and per-IP daily usage limits. It omits result-count limits or pagination behavior, which keeps it short of a 5.

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 with zero filler: purpose, output shape, sibling differentiation, and the free-tier caveat. The differentiating constraint (lighter/faster) is front-loaded rather than buried.

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 does describe the return shape (terms with a priority score, higher = more searched) and the access/rate-limit context. It doesn't state how many suggestions come back or whether country materially changes results, a minor residual gap.

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 seed, store, and country are all already documented with format details (ISO code, default 'us', enum values). The description adds no parameter-level detail beyond that, so the 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 (get autocomplete suggestions) and resource (for a seed keyword from the App Store or Google Play), and explicitly contrasts itself with the close sibling sonar_keyword_search. An agent can distinguish it from other keyword tools 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?

It gives an explicit when-to-use condition ('use when you only need term ideas without difficulty/popularity scoring') and names the alternative tool by name. The routing decision between the lightweight suggestions tool and the heavier search tool is fully specified.

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