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

Annotations only declare readOnly/openWorld; the description adds genuinely useful context beyond them — data origin (socialblade.com public profile pages), access path (residential proxy), history depth (~15 days), a hedge that some metrics exist only 'where Social Blade has them,' and a precise cost model ($0.002 USDC per successful call via x402, failures not charged). This is exactly the behavior an agent needs before committing a paid 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?

Purpose and field coverage are front-loaded in the first sentence, with sourcing/pricing pushed to the end where it belongs. It is dense but every clause (data points, history window, proxy, price, no-charge-on-failure) adds information.

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?

An output schema exists, so return values need no explanation, and annotations cover the safety profile. The description fills the remaining gaps an agent would care about: data provenance, history limits, partial-data hedging, and the payment/failure semantics.

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%, so the handle format and the platform list are already fully documented in the schema; the description only restates the platform set. Baseline 3 is appropriate when the schema carries parameter meaning.

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 (fetch statistics) and resource (Social Blade creator stats) and enumerates the returned fields: follower/view/upload counts, engagement rate, grade/rank, country/category, and ~15 days of history. It never names the platform-specific siblings (social_youtube, social_instagram_profile, social_tiktok_profile) that could also be used for some of this data, so sibling differentiation is implied rather than stated.

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 makes the use case clear (cross-platform creator statistics sourced from Social Blade's public profiles) and discloses the paid invocation model, but it gives no explicit when-to-use/when-not guidance or comparison against the many platform-specific social_* siblings that overlap with it.

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