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

Annotations already declare read-only, idempotent, non-destructive, open-world behavior, so the description is free to add value elsewhere and does: it discloses page-size limits (20 default, 50 with count) and per-call credit cost, including the extra credit charged for the username lookup. It does not explain pagination behavior or whether cursors expire, which keeps it short of 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?

Two sentences, front-loaded with the primary action and ordering, followed by the two facts an agent most needs before calling: result cap and credit cost. No redundant restatement of the title or schema.

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 read-only list tool with full schema coverage and no output schema, the description covers ordering, page size, identifier choice, and cost. It stops short of saying what a returned video record contains, which would matter slightly given the absence of an output schema.

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 the schema already documents count, cursor, secUid, and uniqueId. The description only restates the credit differential that the schema also carries, adding no new syntax or format detail; 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?

"List a TikTok creator's videos, newest first" gives a specific verb, resource, and ordering, which distinguishes it from tiktok_comments and tiktok_profile by resource type. It never names tiktok_search as the boundary case, so an agent wanting video content still has to infer which of the two list-like tools to pick.

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 requirement of either a username or secUid, and the credit-cost sentence effectively guides the choice between the two identifier paths. There is no explicit when-to-use/when-not guidance against siblings such as tiktok_search or tiktok_profile.

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