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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds that the output is a set of tab keys and gives examples of the values, which is useful context beyond the annotations, but it says nothing about whether tabs vary by region/account or how many are typically returned.

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?

One front-loaded sentence with the verb and resource first and the enumerable values last; no filler, no repetition of the tool name, nothing that could be cut.

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 an output schema present, the return shape needn't be described, and the single required parameter is fully covered by the schema. The description is adequate for this narrow lookup, though it omits the practical note about what to do with the returned keys (feed them into the tab-specific search siblings).

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?

The single 'keyword' parameter is 100% documented in the schema ('Search keyword whose available tabs to retrieve'), and the description only restates the same idea in prose. No additional syntax, normalization, or language hints are added, so the schema does all the work.

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?

Specific verb ('Retrieve') plus resource ('tab keys TikTok offers for a search keyword') and an enumeration of the possible tab values (video, music, live, place, hashtag). An agent can distinguish this from siblings like tiktok_mobile_search or tiktok_mobile_search_hashtags because it clearly returns tab metadata rather than search results. It stops short of naming a sibling explicitly, so it is a clear 4 rather than 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?

Usage is only implied: an agent must infer that this is a discovery step used before calling tab-specific search tools (tiktok_mobile_search_music, tiktok_mobile_search_place, etc.). There is no explicit when-to-use statement, no exclusions, and no named alternative.

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