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

Annotations already declare readOnlyHint=true, destructiveHint=false, openWorldHint=false, but the description adds substantial behavior beyond them: results carry public metadata and exact music_id only (no temporary URLs, signatures, tokens, or raw provider payloads), the server revalidates the id on the exact create route before issuing an approval, and saved templates retain an explicit track that preparation re-verifies.

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?

Well front-loaded: the library/scope statement comes first, then result-content caveats, then required/optional parameters, then an example. It is dense and every sentence is informative, though the saved-template and local-carousel sentences sit slightly off the core path of discovery and cost a bit of length.

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 read-only search tool with no output schema, the description explains what results contain, what is deliberately omitted, the required/optional parameters with ranges, pagination behavior, and how the returned music_id is consumed downstream. Nothing an agent needs to call it correctly is missing.

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 0%, so the description carries the full burden and does so well: advertiser_id must come from assets_list_ad_accounts, search is 1-100 characters, limit ranges 1..50, and cursor is the opaque next_cursor from the previous page with serial pagination rules. An example call is included.

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?

States a specific verb and resource: searches TikTok's live advertiser-available music library, scoped to Smart+ SINGLE_IMAGE or CAROUSEL_ADS creation. It even delineates a boundary against a sibling by noting local carousel members come from creatives_list via image_creative_ids, so an agent can distinguish it without opening other schemas.

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?

Explicitly tells the agent to select a row with create_eligible=true and the required image format, then pass its music_id as ad_params.music_info.music_id. It also gives when-not guidance ('never guess or assume cross-advertiser availability') and pagination discipline (keep the same advertiser_id/search/limit, paginate serially, never fan out).

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