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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds some context by naming the data source ('Nuqti SERP') and implying live/current SERP results, but it says nothing about latency, rate limits, quota cost, or behavior for unknown/low-volume keywords — a notable omission for a paid external data lookup.

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?

A single dense sentence with no filler; every item listed is a real return field. It is front-loaded with the core metric (search volume) though the lack of any sentence break makes the long enumeration slightly harder to scan.

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 usefully enumerates the return payload, which is genuinely needed. However, for a 2-parameter, multi-market tool it omits the market parameter's effect, prerequisites, and any usage context, so it is adequate but incomplete.

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 only 50%: country has an enum plus a short description, while keyword has none. The description never mentions the country/market parameter at all, even though keyword metrics are highly locale-dependent, so it fails to compensate for the coverage gap or clarify what 'keyword' should contain (single term vs phrase).

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 enumerates the metrics returned for a keyword (volume, difficulty, CPC, intent, SERP, PAA), which implies the purpose of fetching keyword research data, but it never states a verb or scope explicitly — it reads as a field list rather than a purpose statement. It also does nothing to distinguish itself from the sibling keyword_ideas tool, so an agent must guess which one to pick for a given research need.

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?

There is no when-to-use guidance, no when-not-to-use, and no named alternative despite several plausible siblings (keyword_ideas, domain_overview, backlinks_summary, run_seo_tool). The agent gets no signal about whether this is for a single keyword lookup versus bulk discovery.

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