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

Adds real behavior beyond the readOnly/openWorld annotations: results are limited to public About-page data, moderator/admin fields appear only 'when Facebook exposes them', and lookups incur cost with repeated requests re-purchasing data. However, the cost disclosure is internally inconsistent — 'at least 10 Nexscope credits' versus '1 credit per request' — which leaves the agent with a contradictory billing picture.

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 useful content is front-loaded and well formed, but roughly half the text is pasted marketing/API-doc boilerplate ('Facebook Facebook Group Info API View Pricing Get the public About-page information...', 'Examples are not guaranteed prices') that repeats the title and restates pricing with a conflicting number.

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?

With no output schema, the description usefully enumerates the returnable fields (counts, categories, admins, rules, history), and it covers the identifier requirement and cost model. The remaining gap is the self-contradictory credit figure, which undermines the one piece of operational context the annotations cannot supply.

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 both parameters are documented in-schema, so the baseline applies. The description's 'Provide either url or group_id' does add the at-least-one-required nuance that the schema (empty required array, no oneOf) does not express, but adds nothing on formats beyond what the schema already states about sub-page URLs and numeric IDs.

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?

Opens with a specific verb+resource ('Fetches the public information shown on a Facebook group's About page') and then enumerates the exact contents: description, privacy/visibility, member and activity counts, categories, admins/moderators, history, rules. This clearly separates it from siblings like social_facebook_group_posts or social_facebook_profile.

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 gives input-selection guidance ('Provide either url or group_id') but never states when to choose this tool over adjacent siblings such as social_facebook_group_posts or social_facebook_profile, nor any exclusions. Usage is implied by the About-page framing rather than stated.

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