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

With no annotations, the description carries the full burden and does reasonably well: it discloses page size (~10 posts per page), pricing model (per page, 1 credit, default 1 page), and the required Authorization header. It omits rate limits, what 'recent/public' excludes, and error behavior, but covers the key operational facts.

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?

The core sentence is front-loaded and efficient, but the trailing block ('Platform=tiktok resource=posts. Costs 1 credit(s). Requires Authorization... Credits unit: page.') is metadata-style duplication of the per-page pricing statement, plus a double-period typo. Mildly cluttered.

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?

For a simple fetch tool with no output schema, the description covers auth and cost but says nothing about return shape (list of videos plus a nextCursor) even though start_cursor implies pagination. Adequate but leaves the response contract for the agent to guess.

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 depth, username, and start_cursor are already documented in the schema, including the ~10 posts per page detail. The description's '~10 posts per page' and 'defaults to 1 page' merely restate schema content, 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+resource+scope: 'Fetch recent public videos for a username.' The 'for a username' scoping distinguishes it from siblings like tiktok_search and tiktok_user without naming them explicitly. Clear enough to select, though it never explicitly contrasts with tiktok_post or tiktok_search.

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 by the username-based fetch and the disclosed per-page pricing, but there is no explicit when-to-use/when-not guidance versus siblings such as tiktok_search or tiktok_post. An agent must infer the choice from the resource name alone.

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