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

Annotations already mark it read-only and open-world, but the description adds substantial context they cannot express: the data comes from embedded page data rather than the official API, anonymous access limits, 404 on deleted/private videos, and a per-call price of $0.002 USDC via x402 with failed calls uncharged. Cost and billing behavior is exactly the kind of trait an agent needs before invoking a paid tool.

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 access constraints are front-loaded, and pricing/error behavior closes the text. The long enumeration of returned fields is somewhat redundant given an output schema exists, so a little length is not fully earned, but no sentence is filler.

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 covers return shape, and the description fills the remaining gaps an agent would need: access tier, error semantics, and payment mechanics. Nothing required to call this 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 already gives the canonical URL form, so the schema carries most of the burden. The description adds that the URL must point at a single video page (as opposed to profile or hashtag pages), which clarifies rejection conditions beyond the schema's format hint.

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 ('One public TikTok video by URL') and specifies the extraction source ('the video page's embedded data'), then enumerates the returned fields. That scope implicitly distinguishes it from social_tiktok_comments, social_tiktok_profile and social_tiktok_hashtag_analytics, which target different TikTok 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?

Explicitly scopes when the tool applies and rules out adjacent use cases ('Keyword, hashtag and profile video lists are not available anonymously') and documents the failure case ('Deleted or private videos return 404'). It stops short of naming the sibling tools that would handle those excluded cases, leaving the agent to infer them from the sibling list.

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