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

Annotations are absent, so the description carries the full behavioral burden. It adds a pricing trait ('Free... No payment') and names output fields, but omits auth requirements, rate limits, read-only/no-side-effect confirmation, and error behavior.

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?

One compact sentence/fragment with no filler and front-loaded purpose. 'No payment' is somewhat redundant with 'Free,' but the description remains efficient.

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 one-parameter tool with no output schema and no annotations, the description is minimal but mostly adequate: it names the returned fields (title, description, image, icon). It still leaves return structure and error/fallback behavior unspecified, so completeness is only fair.

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 single url parameter is fully described in the schema (absolute http(s) URL, example), and the description adds no syntax or format beyond that. With 100% schema coverage and one parameter, 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 resource and return fields: Open Graph metadata (title, description, image, icon) for a URL. It distinguishes this from generic capture/analyze siblings by focusing on OG metadata, but it does not explicitly name or contrast with any sibling, so not a 5.

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 guidance on when to choose webcap_og over webcap_preview, webcap_extract, or other siblings. The only contextual hint is 'No payment,' which implies a free tier but not a use case or exclusion.

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