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

No annotations are provided, so the description carries full burden. It notes 'server-side' and 'keyless trial', but fails to disclose important behaviors like error handling, rate limits, or whether the operation is read-only. The potential for trial limitations or silent failures is not addressed.

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?

A single, well-structured sentence that immediately states the action and scope. No extraneous information; every word serves a purpose.

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?

With no output schema, the description enumerates the returned metadata fields (title, description, preview image) which is helpful. However, it omits typical return format, error scenarios, and limitations (e.g., only works on pages with OG tags). The tool is simple so this may be adequate, but gaps remain.

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 coverage is 100% with a single parameter 'url' described as 'The page URL to inspect.' The tool description adds context that this URL will be used to fetch metadata, but does not add new constraints or format details 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 states the verb 'Fetch' and the resource 'URL's Open Graph / Twitter card metadata', listing specific fields (title, description, preview image). It differentiates from siblings like cors_fetch or email_validate by specifying the unique functionality.

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?

No explicit guidance on when to use this tool versus alternatives such as cors_fetch for raw fetching or naics_match for industry codes. The mention of 'Keyless trial' is a caveat but does not help an agent decide tool selection.

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