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

Annotations already declare readOnlyHint=true and openWorldHint=true, covering the read-only, network-access safety profile. The description adds useful context about the target being a public page and the $0.002 per-call cost via x402. It does not disclose potential failure modes (e.g., blocked pages, missing metadata fields) but adds meaningful context beyond the annotations.

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?

A single sentence efficiently lists the output fields, followed by the pricing detail. No filler or redundant phrasing, and the most important content (what the tool returns) is front-loaded.

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, read-only tool with annotations and no output schema, the description adequately lists all returned metadata fields and the cost. It lacks details on edge cases like pages with missing metadata or scraping restrictions, but the core behavior an agent needs to invoke the tool correctly is present.

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 only parameter, url, is fully described in the schema (format: uri, description: 'Public http(s) URL'). The description adds no additional parameter semantics, but with 100% schema coverage, the schema already carries the burden, so baseline 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 enumerates the specific metadata fields returned (title, description, canonical URL, language, site name, author, publish date, image, JSON-LD) with a clear verb 'get' and precise resource. This distinguishes it from the sibling read_web_page, which likely returns page content, without needing to inspect 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 implies usage for metadata-only extraction from public pages and notes the cost, but it does not explicitly state when to use this tool over read_web_page or the x402 service tools, nor does it provide exclusions or conditions for selecting an alternative.

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