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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, covering safety. The description adds valuable behavioral context: cost per row ($0.09), row limit (up to 20), header exclusion, error handling (4xx/5xx not charged), and response format (semicolon-delimited text). These details go beyond annotations and inform the agent about side effects and output parsing. This is a strong addition, though it doesn't mention pagination (but the limit is clear).

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?

The description is two sentences with no wasted words. It front-loads the core purpose, then adds cost and format details. Every piece of information earns its place, and the structure is logical: what, then cost, then response format. This is highly concise and well-structured.

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 that an output schema exists, return values are already structured. The description covers purpose, cost, row limit, and response format. Combined with annotations (read-only, idempotent) and the input schema, an agent has enough to call the tool correctly. The only gap is explicit sibling differentiation, but that falls under usage guidelines rather than completeness. It is quite complete for a simple retrieval tool.

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 both parameters (domain and database) are fully documented with examples. The description adds no additional parameter semantics—it doesn't elaborate on format or constraints beyond what the schema provides. Per the rubric, when schema coverage is high, the baseline is 3, and the description doesn't need to compensate.

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 clearly states the tool returns keywords a domain ranks for in Google organic, with specific fields (position, volume, CPC, URL). This is a specific resource and action, but it doesn't explicitly contrast with siblings like get_semrush_domain_overview or get_semrush_organic_results. The purpose is evident and distinct, but lacks explicit differentiation.

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 description gives no explicit guidance on when to use this tool versus alternatives. There is no mention of conditions or exclusions relative to sibling tools. Usage is implied by the tool's name and purpose, but the description doesn't state 'use this for X instead of Y'. Since it's a straightforward retrieval, the lack of explicit guidance is acceptable but not ideal.

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