Open Graph

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

Annotations already provide safety hints (readOnlyHint, destructiveHint false). The description adds context about the tool being separate from the witness protocol and potential x402 pricing, going beyond the annotations. No contradictions.

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 two sentences: first states purpose, second adds contextual info about pricing and separation. It is efficient without unnecessary details, earning a high score for conciseness.

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 tool that extracts standard metadata (Open Graph, Twitter card), the description gives enough context. No output schema exists, but the purpose implies the structure. Additional details could mention typical fields, but overall complete.

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%, both parameters have clear descriptions. The tool description does not add further parameter semantics, but the schema already handles it adequately. Baseline score of 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?

The description clearly states the action ('Extract Open Graph and Twitter card fields') and the purpose ('to preview how a URL will render in feeds and agents'). This distinguishes it from sibling tools like 'util_page_extract' which extract different content.

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 implies usage for previewing URL rendering in feeds/agents, but does not explicitly state when not to use it or provide alternatives. No exclusions or comparisons to other util_* tools are given.

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