Ad Library Ad

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

Annotations declare readOnlyHint=false and destructiveHint=false, so the safety profile is partly covered. The description adds genuinely useful context beyond them: paid credit consumption, the confirm=true gate, the Top Ads → Ads Library fallback order, and how unexposed fields are returned (null/empty/false). It also clarifies the POST does not publish, resolving the apparent contradiction with a read-like operation.

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?

Four sentences, front-loaded with the core action and source-resolution behavior; the null-field caveat is useful. Minor redundancy between the first sentence and the schema's ad_id description, but nothing wasteful.

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?

No output schema exists, so the description carries some return-value burden and appropriately explains the shared response shape and null-field behavior. Combined with the confirm/credit warning and source fallback, it is close to complete for a 3-param, single-ad fetch tool.

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 all three parameters are already documented. The description restates the dual ID/URL acceptance but adds no syntax, format, or edge-case guidance beyond what the schema provides, so it lands at the baseline.

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 (fetches) and resource (one TikTok ad) and clarifies it accepts either an ID or URL. It also distinguishes itself from the sibling tiktok_ad_library_ad_library_search by describing single-ad retrieval and the dual-source resolution order, so an agent can tell them apart without opening 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?

Implied usage (retrieve a single ad when you already have an ID/URL) is clear, and it notes confirm=true is required, but it never explicitly states when to prefer this over the sibling search tool or what inputs select each source.

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