Fetch 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 fetching and returning HTML but omits critical details such as error handling (e.g., for invalid URLs or network failures), authentication needs, rate limits, or whether it performs any processing (like sanitization). This is a significant gap for a tool that interacts with external resources.

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 with zero waste—it directly states the action, resource, and output. It is appropriately sized and front-loaded, making it easy for an agent to parse quickly.

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 of fetching external websites (which involves network calls and potential errors), no annotations, and no output schema, the description is incomplete. It should address behavioral aspects like error cases, timeouts, or content limitations to help the agent use it correctly in varied contexts.

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 100%, so the schema already documents both parameters (url and headers) adequately. The description adds no additional meaning beyond what the schema provides, such as examples or constraints on URL formats or header usage. Baseline 3 is appropriate when the schema does 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 with a specific verb ('fetch') and resource ('a website'), and indicates the output format ('return the content as HTML'). It distinguishes from sibling tools by specifying HTML output, though it doesn't explicitly contrast with fetch_json, fetch_markdown, and fetch_txt beyond the format difference.

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 like fetch_json or fetch_markdown. It lacks context about scenarios where HTML is preferred over other formats, prerequisites, or exclusions, leaving the agent to infer usage based solely on output format.

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