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

Annotations already cover read-only, non-destructive, open-world behavior. The description adds important unannotated behavior: pay-per-call in stablecoins and no charge for private, unknown, or non-page inputs. It does not detail auth or rate limits, but those are less central for this lookup.

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 compact sentences with the return fields and cost policy front-loaded. There is little waste; even the pricing and failure-policy sentence earns its place.

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 JSON format. Together with the fully described single input parameter and the annotations covering safety/open-world behavior, this is enough for an agent to invoke the tool correctly.

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 by the schema, including an example and the exclusion of profiles/groups. The description reinforces that the URL must be a public Facebook page and that only one page is processed per call, but adds no new syntax or format details beyond the schema, so the 100% coverage baseline 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?

States a specific action (send the URL of a public Facebook page) and a specific result (public page details as JSON, including name, category, followers, intro, website, and contact fields). The resource is clearly page details rather than posts/comments, and the scope excludes private/unknown/non-page inputs.

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?

Provides clear usage context: one public Facebook page URL per call, returning page details. It also states private, unknown, or non-page inputs are not charged, which helps avoid misuse, but it does not explicitly route agents to facebook-posts or facebook-comments alternatives.

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