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

Beyond the readOnlyHint/openWorldHint annotations, the description discloses substantive behavior: numbers are stored and refreshed roughly hourly, cover_url links expire in a few hours, and needs_reconnect signals a required re-authorization with analytics permissions. It also explains the by_day series semantics (stats as last seen each UTC day), which is exactly the operational context an agent needs.

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?

Content is front-loaded: the resource and scope come first, return fields second, caveats last. The main sentence is a dense run-on, but nearly every clause carries information; no filler sentences.

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 does the work of describing return values (lifetime views/likes/comments/shares, by_day series, cover_url, needs_reconnect) plus freshness and expiry caveats. Only minor gaps remain, such as ordering/pagination beyond 'newest first' and the limit cap, which the input schema covers.

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 days/limit/account_ids are already documented. The description reinforces the 7/30/90 day window but adds no meaning for limit or account_ids, so it does not exceed the schema baseline.

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?

The description opens with a specific verb+resource+scope: 'Every public video on the user's connected TikTok accounts posted in the last 7, 30 or 90 days', and clarifies that videos are included regardless of how they were posted. It is clearly distinguishable from siblings like get_post or list_posts, though it never names those siblings explicitly.

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?

Usage is implied rather than stated: the 'by_day ... to see which posts are still growing' clause tells the agent this is the tool for tracking video performance over time. There is no explicit when-not-to-use guidance or named alternative (e.g., get_analytics vs list_posts), leaving routing to inference.

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