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

Beyond the annotations, which already mark the call as read-only and nondestructive, the description discloses important behavioral traits: per-row billing at $0.09, a 20-row cap with header row excluded, that 4xx/5xx are not charged, and that the response is semicolon-delimited text. This is unusually transparent about cost and response format.

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 sentences, each earning its place: the first states the core function, the second covers the critical billing behavior, and the third discloses the response format. The most differentiating information is front-loaded and there is no filler.

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?

Given the annotations already establish safety and idempotency, an output schema exists for return values, and the parameter schema covers the required inputs, the description fills the remaining gaps: pricing, row limits, error-charge behavior, and text delimiter format. Nothing needed to call this tool correctly is missing.

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 schema already documents both parameters (domain and database) with examples, so schema_description_coverage is 100%. The description adds no additional semantics about how domain or database values should be formatted beyond what the schema provides, making the baseline 3 appropriate.

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 states a specific deliverable — 'Historical rank, organic traffic and keyword-count trajectory for a domain' — with a clear resource and scope. This differentiates it from siblings like get_semrush_domain_overview and get_semrush_domain_organic_keywords, which are not historical trajectory tools.

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?

The 'Historical ... trajectory' phrasing implies this is for time-series domain metrics rather than current overviews or keyword lists, but the description never explicitly says when to use this tool versus the many Semrush/DataForSEO siblings. There are no exclusions or alternative tool mentions, so usage guidance is only implied.

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