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 describes a read-only operation ('Retrieves'), which is helpful, but lacks details on permissions, rate limits, error handling, or what the returned list includes (e.g., format, fields). For a tool with zero annotation coverage, this is insufficient, as it doesn't fully inform the agent about how the tool behaves beyond the basic action.

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 concise and front-loaded, with the main purpose stated in the first sentence and a usage note in the second. Both sentences earn their place by providing essential information without redundancy. It could be slightly improved by integrating the usage note more seamlessly, but overall, it's efficient 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 the tool's complexity (a retrieval operation with 1 parameter), no annotations, no output schema, and low schema description coverage, the description is incomplete. It lacks details on behavioral aspects (e.g., authentication, response format) and doesn't fully explain the parameter semantics. While it states the purpose and a prerequisite, it doesn't provide enough context for the agent to use the tool effectively without additional guesswork.

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 input schema has 1 parameter with 0% description coverage, meaning the schema provides no semantic information. The description mentions 'using the project's unique identifier,' which clarifies that 'project_id' refers to a project identifier, adding some meaning. However, it doesn't explain what a valid 'project_id' is (e.g., format, source, or constraints), so it only partially compensates for the low schema coverage.

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: 'Retrieves the list of competitors associated with a specific Rank Tracker project in Ahrefs, using the project's unique identifier.' It specifies the verb ('Retrieves'), resource ('list of competitors'), and context ('Rank Tracker project in Ahrefs'). However, it doesn't explicitly differentiate from sibling tools like 'rank-tracker-competitors-overview' or 'site-explorer-organic-competitors', which might offer similar functionality, so it doesn't reach a perfect score.

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 provides some usage guidance by stating 'Use doc tool first to get the real input schema,' which implies a prerequisite step. However, it doesn't specify when to use this tool versus alternatives (e.g., other competitor-related tools in the sibling list) or any exclusions. The guidance is implied rather than explicit, making it adequate but with gaps.

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