Check how a link will look when shared

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

With no annotations provided, the description carries the full behavioral burden. It discloses that the tool fetches the URL, loads og:image, verifies reachability, raster format, approximate dimensions, and platform size limits, and returns the image. This goes beyond a generic 'checks the link' and gives the agent a clear picture of what happens and what the output is.

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 compact and front-loaded: primary purpose first, then the specific checks performed, then the output. Every sentence contributes useful information and there is no redundancy or filler.

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 tool with no output schema, the description explains the return value ('Returns the image so you can see it') and the core behavior well. It does not mention failure modes or error handling, but the information provided is sufficient for an agent to invoke the tool correctly and interpret its primary result.

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% and the 'url' parameter is already well documented in the schema, including live URLs, preview deployments, and localhost. The description adds only general context ('on a URL') without adding parameter-level meaning beyond the schema, so the baseline of 3 is appropriate.

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 names a specific verb ('Check') and a specific resource ('Open Graph and Twitter card tags on a URL'), then adds concrete detail about rendering on named platforms. This clearly distinguishes it from sibling tools like check_security_headers and check_routes without needing to open their schemas.

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 makes the usage context clear: use this when you need to inspect social sharing tags or preview how a link appears on LinkedIn, X, Slack, iMessage, and Discord. It does not explicitly state when not to use it or name alternatives, but the platform-specific preview behavior is sufficient contextual guidance for an agent to select it appropriately.

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