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 options to 'filter, sort, and customize returned fields by country' and references a 'timeout' parameter, hinting at potential performance constraints. However, it lacks critical details such as rate limits, authentication requirements, data freshness, or what happens on errors. For a tool with 8 parameters and no annotations, this is insufficient.

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: the first states the purpose and features, and the second provides a usage instruction. It's relatively concise but includes an unnecessary directive ('Use doc tool first') that might be better placed elsewhere. The structure is front-loaded with core functionality, but could be more streamlined by integrating the instruction more naturally.

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 complexity (8 parameters, 0% schema coverage, no annotations, no output schema), the description is incomplete. It outlines the tool's purpose and hints at some parameters but fails to provide adequate behavioral context, parameter details, or output expectations. For a data retrieval tool with multiple filtering options, more comprehensive guidance is needed to ensure correct usage.

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 8 parameters have descriptions in the schema. The description adds some context by mentioning 'filter, sort, and customize returned fields by country' and 'specified queries or keyword lists', which loosely maps to parameters like 'where', 'order_by', 'select', 'keywords', and 'keyword_list_id'. However, it doesn't explain specific parameter roles, formats, or constraints, leaving significant gaps in understanding.

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 keyword search suggestions and related keyword metrics (e.g., search volume, difficulty, CPC) for specified queries or keyword lists.' It specifies the verb ('provides'), resource ('keyword search suggestions and related keyword metrics'), and examples of metrics. However, it doesn't explicitly differentiate from sibling tools like 'keywords-explorer-matching-terms' or 'keywords-explorer-related-terms', which likely have overlapping functionality.

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 a usage instruction: 'Use doc tool first to get the real input schema.' This provides a prerequisite but doesn't guide when to use this tool versus alternatives. No explicit when/when-not scenarios or comparisons to sibling tools are provided, leaving the agent without clear selection criteria among similar keyword explorer tools.

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