Fetch URL

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations provided, the description carries the behavioral disclosure burden. It states that this is a fetch operation returning content and discloses the key transformation: HTML pages are converted to markdown. It does not mention error handling, redirects, or rate limits, but for a simple read-only fetch tool the described behavior is sufficiently transparent.

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?

Three short sentences, each earning its place: the fallback condition, the core fetch behavior, and the markdown conversion behavior. There is no filler, redundancy, or unnecessary detail. The most important usage guidance is front-loaded.

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?

For a simple two-parameter tool with full schema coverage and no output schema, the description plus schema is sufficient to call the tool correctly. It explains when to use it, what it does, and the default conversion behavior. Minor edge cases like non-HTML handling are not covered but are not critical for invoking it correctly.

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 baseline is 3. The schema already documents both 'url' and 'raw' parameters well. The description's mention of markdown conversion aligns with the 'raw' parameter's purpose but does not add significant parameter-level meaning beyond what the schema provides.

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 identifies the core action: 'Fetches a URL and returns the content.' It also frames the tool as a fallback to the built-in web fetch tool, which distinguishes its purpose and place in the tool ecosystem. The verb, resource, and intended role are all explicit.

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 explicitly states when to use this tool: if the built-in web fetch tool fails, retry with this MCP tool as a fallback. It names the alternative tool and implies the built-in tool should be attempted first. This leaves no ambiguity about use versus alternatives.

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