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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds valuable context beyond that: the feed is public, region-dependent, a recommended sample rather than a global ranking, and paginated via a returned cursor. This sets expectations about data nature and sampling that annotations cannot convey.

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?

Three tight sentences with no filler; the core purpose and payload are front-loaded, followed by pagination and the scope caveat. Each sentence earns its place, though the scope caveat could be folded more tightly.

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 an output schema present, the description does not need to explain return values, and it correctly focuses on behavior and scope. For a two-parameter read-only feed tool, the sampling caveat and pagination note make it complete enough for an agent to invoke 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 description coverage is 100%, so both 'count' (default/max behavior) and 'cursor' are already documented in the schema. The description reinforces cursor-based pagination but adds no syntax or format detail beyond the schema. Baseline 3 is appropriate when the schema does the heavy lifting.

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 (Retrieve) and resource (public TikTok mobile For You feed) and names the payload (video and statistics objects). It distinguishes itself from trending-ranked siblings by clarifying it is a 'region-dependent recommended sample, not a global trend ranking', which is a meaningful scope distinction even without naming a specific alternative tool.

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 pagination guidance ('Use the returned cursor for another page'), which is useful operational context, but it does not state when to choose this tool over siblings like tiktok_trending or tiktok_mobile_search. Usage is implied by the scope note rather than explicitly instructed.

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