fetch

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

The description discloses key behaviors beyond annotations: uses Servo browser with JS/CSS, strips navbars/sidebars/footers automatically, truncates content, paginates, and provides accessibility tree. These details are not in annotations (readOnlyHint, idempotentHint, etc.) and significantly aid agent understanding.

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 concise (4 sentences) and front-loaded with the main purpose. Each sentence adds distinct value: engine details, automatic stripping, optional selector, format options, pagination. No wasted words.

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 tool with 7 parameters and no output schema, the description covers core functionality, parameter usage, and behavioral traits well. It lacks explicit error handling or rate limit info, but annotations provide safety signals. Overall, it is sufficient for effective tool use.

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?

All 7 parameters have schema descriptions, so baseline is 3. However, the tool description adds value by explaining the purpose of key parameters (selector for specific extraction, settle_ms for SPA hydration, start_index for pagination) beyond the base 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 clearly states the tool fetches a URL and extracts readable content using the Servo browser engine. It distinguishes from siblings like screenshot or execute_js by specifying its unique features (JS execution, CSS layout, readability extraction). The mention of selector, format, and pagination adds specificity.

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 gives clear guidance on when to use optional parameters (selector for specific sections, format for accessibility_tree, start_index for pagination). It does not explicitly contrast with siblings, but the context implies when alternatives are better (e.g., screenshot for visual, crawl for multiple URLs).

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