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

Annotations already declare readOnlyHint=true and destructiveHint=false. The description adds context about the two modes and default behavior, but does not disclose additional behavioral traits like rate limits, auth requirements, or failure handling. This is acceptable given the strong annotation coverage.

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 two sentences, front-loaded with the core function, and adds mode guidance in the second sentence. No wasted words; every sentence earns its place.

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 3-parameter tool with a nested schema, the description explains the two modes and provides concrete examples, which is sufficient for an agent to select and invoke it. It does not cover error handling or exact return format for markdown, but that is not essential for selection.

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%, with each parameter (url, mode, schema) documented. The description adds example fields (price, title, author) and clarifies the two modes, but most parameter meaning is already in the schema. There is modest added value beyond the schema.

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 uses specific verbs like 'Fetch' and 'extract' with a clear resource ('public web page'). It clearly distinguishes two modes (markdown and structured) and the tool's purpose is distinct from sibling rendering/screenshot tools.

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 explicit mode selection guidance ('Use markdown mode to summarize or quote...', 'use structured mode to pull specific named fields...'). However, it does not explicitly mention sibling tools or when not to use this tool, so it stops short of full exclusions or alternatives.

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