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

Annotations already declare readOnlyHint and openWorldHint, so the safety profile is covered. The description adds genuinely useful behavioral context beyond that: a cost of 1 AI credit per call charged across all keywords, refunds on failed lookups, and default US/monthly data. It stops short of describing latency, rate limits, or error semantics.

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 front-loaded sentences, each carrying real information: metrics and scope first, then cost/refund behavior, then plan context. The closing sentence about Starter and Growth plans is the weakest, reading slightly like marketing copy rather than agent-relevant instruction.

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 burden of naming the returned fields (volume, difficulty, CPC, intent), which is the key information an agent needs to decide whether this tool answers its question. Missing return shape/pagination detail and any guidance on partial failures beyond the refund note.

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% and the single array parameter (1-10 keywords) is fully documented there, so the baseline of 3 applies. The description's 'monthly, US by default' adds data-source context but hints at a locale option that no parameter exposes, which is mildly confusing rather than clarifying.

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 verb+resource and enumerates the exact metrics returned (search volume, difficulty 0-100, CPC, search intent) plus the 1-10 keyword scope. It does not, however, distinguish itself from the sibling get_keyword_ideas, which an agent could easily confuse with this tool.

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?

Usage is implied by the input constraints (1 to 10 keywords) and the cost statement, but there is no explicit when-to-use guidance and no mention of the obvious alternative get_keyword_ideas. The agent must infer the boundary between fetching metrics for known keywords and generating new ideas.

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