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

Goes well beyond the readOnly/openWorld annotations: discloses that private groups yield only the header, that only the first page of posts is returned, that access goes through a residential proxy from facebook.com, and that billing is $0.01 USDC per successful call via x402 with failures not charged. These are exactly the constraints an agent needs before spending money on a call.

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 dense paragraph is front-loaded with purpose and return shape, then limitations, then pricing. It is efficient but packs return fields and billing into the same block, making it slightly heavy to scan.

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?

Despite an output schema existing, the description is complete: cost model, authentication/payment path, and the private-group edge case are all covered, and the one required parameter is fully specified by the schema. Nothing needed to invoke it correctly is missing.

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 'group' parameter is fully documented in the schema with accepted formats (vanity name, numeric id, URL). The description adds no parameter-level syntax or examples, so baseline 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 verb and resource ('Facebook group snapshot as a logged-out visitor sees it') and enumerates exactly what is returned (name, id, privacy, member count, first-page posts with their fields). This clearly separates it from siblings like social_facebook_pages and social_facebook_posts, which cover different resources.

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 'logged-out visitor' framing and 'first page load' scoping tell the agent when this tool is appropriate (single public group overview, not deep post history). It does not explicitly name alternatives for deeper post/comment retrieval, so no exclusions are stated.

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