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

With no annotations, the description carries full burden. It discloses that extraction is limited to 'visible' content and specifies the data types (emails, phones, social links, URLs). However, it does not mention potential limitations (e.g., reliance on rendered HTML, inability to handle JavaScript-heavy pages, or response structure).

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 sentence of only 13 words, efficiently conveying the tool's purpose with no wasted content. It is front-loaded with the key verb and output types.

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 tool with one parameter, no output schema, and no annotations, the description adequately covers the extraction types. It lacks explicit mention of output format or potential errors, but the low complexity justifies a high score.

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 schema fully documents the single 'url' parameter with a description. The tool description adds the context 'from a page', but this is already implied by the schema's 'The URL to inspect'. No additional semantic value is provided 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 states a specific verb 'Extract' and a clear resource: visible emails, phone strings, social links, and contact-related URLs from a page. This distinguishes it from siblings like 'scrape' which returns raw page content, and 'enrich_lead' which focuses on business lead enrichment.

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 the tool is for extracting contact information from a page, but does not explicitly state when to use it over alternatives like 'scrape' or when not to use it (e.g., for non-renderable pages). No exclusions or prerequisites are provided.

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