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

Annotations already declare readOnly/openWorld/idempotent/not-destructive, and the description adds valuable context beyond them: the per-call billing cost ($0.09, with 4xx/5xx not charged) and the semicolon-delimited response format. No contradiction with the annotations.

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 is front-loaded first, followed by billing disclosure and response format — each sentence earns its place and nothing is redundant.

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?

For a simple 2-parameter read-only tool with a full output schema and comprehensive annotations, the description covers purpose, cost, and format. The only thing missing is routing guidance to related siblings, but the tool's simplicity and structured fields carry the rest.

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%, so the schema already documents both phrase and database parameters with examples. The description only reinforces this with 'keyword phrase in a given regional database', adding marginal value beyond the schema baseline of 3.

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 (Return) + resource (search metrics for a keyword phrase) + scope (regional database), and enumerates the exact metrics returned (volume, CPC, competition, results). This distinguishes it from siblings like get_semrush_backlinks_overview and get_semrush_domain_overview without needing to open their schemas.

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?

Provides no guidance on when to choose this tool over alternatives. Siblings get_semrush_organic_competitors, get_similarweb_keywords, and get_similarweb_keyword_competitors overlap in keyword topics, yet the description never tells an agent which to prefer or under what conditions. This is a clear gap.

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