MCP URL Fetcher

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 fetching and converting to Markdown but does not cover critical aspects such as error handling (e.g., invalid URLs, network failures), authentication needs, rate limits, or what happens if conversion fails. This leaves significant gaps in understanding the tool's behavior.

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 a single, efficient sentence that is front-loaded with the core functionality. There is no wasted language, and it directly communicates the tool's purpose without unnecessary elaboration.

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 moderate complexity (fetching and converting web content) and lack of annotations and output schema, the description is incomplete. It covers the basic purpose but misses behavioral details and output expectations. However, it is adequate for a simple tool with high schema coverage, though it could benefit from more context on limitations or results.

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 'url' parameter fully documented. The description adds no additional meaning beyond the schema, such as URL format constraints or examples. Since schema coverage is high, the baseline score of 3 is appropriate, as the description does not compensate but also does not detract.

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 specific action ('fetch content from any URL') and transformation ('convert to Markdown format'), distinguishing it from sibling tools like fetch-html, fetch-json, and fetch-text by specifying the output format. It uses precise verbs and identifies the resource (URL content).

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 implies usage when Markdown output is needed from a URL, but it does not explicitly state when to use this tool versus alternatives like fetch-html or fetch-text. There is no guidance on exclusions or prerequisites, leaving usage context to inference from the tool name and description.

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