Get link metadata

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

Annotations already declare readOnly, idempotent, openWorld and non-destructive, so safety is covered. The description adds value beyond that with cost ('1 credit') and a performance characterization ('faster and cheaper'), though it says nothing about failure behavior for unreachable URLs or missing meta tags.

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?

Three sentences, front-loaded with what is returned, then purpose, then the cost/performance trade-off. Every sentence carries distinct information.

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?

No output schema exists, but the description enumerates the returned fields and their source (Open Graph, Twitter Card, HTML meta), effectively substituting for it. For a single-parameter read tool with rich annotations, nothing an agent needs is missing.

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 single 'url' parameter is fully documented with format and https:// guidance in the schema. The description adds no syntax or format detail beyond what the schema provides, so the baseline 3 applies.

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?

States a specific verb (extract/get) and resource (link metadata) and enumerates exactly what is returned: title, description, preview images, favicon, site name, plus the source formats. It also implicitly distinguishes itself from siblings like url_to_markdown by being 'faster and cheaper than reading the whole page.'

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?

Gives concrete use cases (summarize a link, build previews, check SEO tags) and a comparative heuristic against the heavier alternative of reading the full page. It stops short of naming the sibling tool (url_to_markdown) or stating when-not to use it.

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