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

Annotations already establish read-only, idempotent, non-destructive behavior, but the description adds important context beyond them: results are newest-first, capped by `limit`, billed per returned row, and contain untrusted user-generated content. The row fields returned are also listed, which helps the agent understand the payload.

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 description is compact and front-loaded, leading with what the tool does and how it differs from the alternative. Every sentence carries useful information about scope, output, cost, or safety, with no 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?

For a two-parameter read tool with no output schema, the description supplies everything needed: selection guidance, return shape, ordering, cost behavior, and a safety caveat about untrusted content. The annotations cover the operation's safety profile, and the description completes the practical context.

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%, so both parameters are already documented. The description adds meaningful semantics for `limit`: it caps rows and therefore cost, and billing is per returned row. It does not add further meaning to `user_id` beyond the schema description.

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 states a specific verb and resource: retrieve comments written by a TikTok user. It also specifies the ordering (newest first) and explicitly distinguishes the tool from `search_tt_comments`, which is text-based across all users. An agent can identify the correct tool without opening the schema.

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 clear use case: see what a specific account says under other videos. It also names the alternative `search_tt_comments` and explains the condition for choosing it (finding comments by text across all users). No inference is required.

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