Open Graph / Twitter card preview check

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

Annotations already establish read-only, idempotent, non-destructive behavior. The description adds meaningful behavioral context beyond that: it reveals network-dependent checks (image reachability, file size, content type) and the fallback behavior when tags are missing. No annotation contradiction exists.

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 one dense, front-loaded sentence that starts with the core action and then lists the specific checks. Every clause adds useful detail; there is no redundant or filler wording.

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 single-parameter read-only tool with no output schema, the description covers the input and the scope of checks comprehensively. It does not describe the exact output format, but the enumerated validation criteria give an agent enough context to understand what will be checked and what the result will likely express.

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 0% and there is one required 'url' parameter. The description compensates by making clear that the URL is the page whose social preview is being validated. For a single obvious parameter, this is adequate, though it does not elaborate on URL formatting requirements beyond the schema's uri format.

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 a specific verb ('Validate') with a clear resource ('how a page previews when shared') and enumerates concrete checks (og tags, twitter:card, image reachability, dimensions, file size, content type, fallbacks). This makes it immediately distinguishable from sibling SEO and site audit 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 clearly implies when to use the tool: whenever social/messaging/AI link-card previews need validation. However, it does not explicitly state when not to use it or name alternative tools, unlike the strongest examples.

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