Ahrefs MCP Server

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It mentions the tool provides metrics 'as of a given date' and has customization options, but fails to disclose critical behavioral traits such as whether this is a read-only operation, potential rate limits, authentication requirements, data freshness, or error handling. For a tool with 6 parameters and no annotation coverage, this is a significant gap in transparency.

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 reasonably concise with two sentences, but the second sentence ('Use doc tool first to get the real input schema') is somewhat redundant as it references external documentation without adding intrinsic value to the tool's purpose. The structure is front-loaded with the core functionality, but could be more streamlined by integrating the parameter mention more effectively.

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 tool's complexity (6 parameters, no annotations, no output schema), the description is incomplete. It lacks details on behavioral aspects, full parameter explanations, output format, and differentiation from siblings. While it hints at prerequisites, it does not provide enough context for an agent to confidently invoke the tool without additional external guidance.

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 0%, meaning none of the 6 parameters have descriptions in the schema. The description lists some parameters ('search scope, protocol, country, and search volume mode') but does not explain their semantics, valid values, or how they affect the output. It also omits details on 'target' and 'date' (the required parameters) and 'mode'. This insufficiently compensates for the lack of schema documentation.

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's purpose: 'Provides SEO performance metrics for a specified domain, URL, or site section as of a given date.' It specifies the verb ('provides'), resource ('SEO performance metrics'), and scope ('domain, URL, or site section'), but does not explicitly differentiate it from sibling tools like 'site-explorer-metrics-by-country' or 'site-explorer-metrics-history', which likely offer similar metrics in different contexts.

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 includes an implied usage guideline: 'Use doc tool first to get the real input schema,' suggesting a prerequisite step. However, it does not provide explicit guidance on when to use this tool versus alternatives (e.g., compared to sibling tools like 'site-explorer-metrics-by-country' for country-specific metrics or 'site-explorer-metrics-history' for historical trends), leaving usage context partially unclear.

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