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

Annotations only declare read-only/non-destructive/non-open-world; the description goes well beyond that by disclosing the receipt lifetime, the cross-tenant/cross-OAuth reuse prohibition, and the exclusion rules with where the filtered-out posts show up (coverage.ineligible_reasons). This is the kind of operational context annotations cannot carry.

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?

Front-loaded and dense with zero filler; the field enumeration earns its place because there is no output schema. It runs long in a single paragraph and mixes purpose, return shape, and validation rules, so structure could be tighter, but nothing is wasted.

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 no-output-schema tool it describes the returned item shape, pagination termination condition, and receipt lifecycle well enough to drive correct repeated calls. The remaining gap is the fully undocumented connection_context parameter and the absence of any error/failure behavior.

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?

With 0% schema coverage the description must carry parameter meaning, and it does for advertiser_id (source: assets_list_ad_accounts), limit (1..50), search (up to 200 chars) and the paging cursor. However it silently omits the connection_context parameter and calls the cursor 'next_cursor' while the schema names it 'cursor', which could cause a minor mismatch.

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 precise verb+resource ('List reusable Spark posts already authorized for one exact TikTok advertiser') and scopes the concept tightly enough that no sibling tool overlaps. An agent can tell this apart from the write-side tools it feeds (campaigns_quick_create) without opening a 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?

Gives explicit when/when-not guidance: pull the listing only until has_more=false and coverage.complete=true, feed eligible fields to campaigns_quick_create(_batch), refresh when a receipt expires, and never reuse a receipt across advertisers or OAuth routes. It also states the negative case ('does not authorize new codes or publish ads').

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