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

Annotations already cover safety (readOnly, idempotent, non-destructive, openWorld), so the bar is lower. The description nonetheless adds real operational context: page size of 20 by default, up to 50 via count, the returned fields (text, author, likes, reply counts), and a cost of 1 credit. It says nothing about cursor-driven pagination or termination conditions, which keeps it from a 5.

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 short sentences, front-loaded with the action, then the return shape, then the use case and cost. Every sentence carries distinct information, with no filler or repetition of the tool title.

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 only three fully documented parameters and no output schema, the definition covers what an agent needs to invoke the tool: pagination limit, fields returned, cost, and the intended reading. The one gap is that pagination behavior across calls is left entirely to the schema's terse cursor description.

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 the schema already documents count (1-50, default 20), cursor and aweme_id. The description only restates the count range and never explains how cursor should be used for paging, so it adds little meaning beyond the schema. Baseline 3 is appropriate.

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 and resource: 'Get the comments on a TikTok video.' That is unambiguous and, together with the tool name, separates it from x_comments by platform. It does not explicitly contrast with sibling tools like tiktok_videos or tiktok_search, so it stops short of a 5.

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?

It gives a concrete when-to-use scenario - 'read buying-intent signals in the buyers' own words, e.g. where can I buy this' - which tells the agent what question this tool answers. It offers no when-not-to-use guidance and does not mention how to continue with the cursor for more than one page, so it is clear context rather than explicit routing.

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