w3c-mcp

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 states the action ('Get') but does not cover critical aspects like whether this is a read-only operation, potential rate limits, authentication needs, or the format of returned data. For a tool with 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 appropriately sized and front-loaded, with the first sentence directly stating the tool's purpose and the second providing helpful context about WebIDL. Both sentences earn their place by adding value without redundancy, making it 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 lack of annotations and output schema, the description is incomplete for a tool that likely returns complex data (WebIDL definitions). It does not explain the return format, potential errors, or behavioral traits, leaving gaps in understanding how to interpret results. With no structured fields to compensate, the description should provide more context.

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 100% description coverage, with the 'shortname' parameter clearly documented. The description adds no additional parameter semantics beyond what the schema provides, such as examples of valid shortnames or constraints. Given the high schema coverage, a baseline score of 3 is appropriate, as the schema handles the heavy lifting.

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: 'Get WebIDL interface definitions for a specification.' It specifies the verb ('Get'), resource ('WebIDL interface definitions'), and target ('specification'), with an additional clarifying sentence about WebIDL's role. However, it does not explicitly differentiate from sibling tools like 'list_webidl_specs' or 'get_w3c_spec', which might offer overlapping functionality, keeping it from 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 no guidance on when to use this tool versus alternatives. With siblings such as 'list_webidl_specs' and 'get_w3c_spec' available, it fails to specify scenarios where this tool is preferred, such as for detailed interface definitions rather than listings or general spec info. This lack of context leaves the agent without clear usage direction.

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