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

Beyond the annotations, the description discloses important behavior: only public post comments visible to a logged-out visitor are returned, typically around 10 "Most relevant" comments from the first page load, and the data comes from facebook.com via a residential proxy. It also specifies pricing and that failed calls are not charged.

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 front-loaded with the core purpose and scope, followed by useful return-field details and pricing. It is dense but mostly earns its length; the return-field list is somewhat redundant because an output schema exists, which slightly reduces 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?

Given the single public-post URL parameter, existing output schema, and read-only/open-world annotations, the description is complete. It covers scope, data source, return contents at a high level, and billing behavior, so an agent has enough information to invoke it 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?

Schema coverage is 100%, and the single url parameter is fully documented in the schema with accepted Facebook post URL formats. The description adds the context that the URL must point to a public Facebook post, but no additional syntax or semantic detail beyond the schema.

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 gives a specific verb and resource: it retrieves comments on a public Facebook post. It also scopes the result to what a logged-out visitor sees on the first page ("Most relevant"), which clearly distinguishes this from tools that fetch posts or full comment threads.

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?

Usage context is clear: the tool is for commenting data on a public Facebook post, with the required input being that post's URL. It does not explicitly name alternatives or exclusions, but the scope is sufficiently clear for an agent to choose it correctly.

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