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

With no annotations, the description carries the full burden. It discloses credit cost (2 credits), free cache hits on cache=true, default-fresh behavior, and that empty results and failures are never charged. This goes beyond the schema and provides meaningful operational context, though it omits rate limits and authentication details.

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 two sentences, front-loads the core operation and output contents, and then packs cost, cache, and failure-policy details without redundancy. Every clause earns its place.

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 four-parameter tool with no output schema and no annotations, the description covers purpose, returned categories, pagination, cost, cache behavior, and no-charge-on-failure. It lacks an explicit return-shape explanation or ordering note, but the schema already documents pagination mechanics and URL constraints, so the remaining gaps are minor.

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 the baseline is 3. The description adds little to parameter meaning beyond what the schema already provides, such as the URL format, platform-match warning, cache behavior, limit defaults, and cursor usage. It doesn't deepen the understanding of the parameters themselves.

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 uses a specific verb and resource: 'List TikTok videos that use a specific sound.' It also enumerates the returned data categories (caption, author, exact engagement, canonical hashtags, mentions), which clearly distinguishes it from broader siblings like tiktok_trending_feed or tiktok_song_details.

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?

The opening clause states the exact condition for use: when a TikTok sound/music URL is available and the agent needs videos using that sound. It doesn't explicitly name alternatives or exclusions, but the context is clear enough for an agent to route correctly.

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