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

Annotations already declare the safety profile (readOnlyHint=false, destructiveHint=false, openWorldHint=false), so the bar is lower. The description adds useful context — that it fetches live data and persists it as a named pack — but does not say whether an existing pack of the same name is overwritten or what auth scopes are required.

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 core action is front-loaded in the first sentence, followed by routing rationale, a REQUIRED block, and an example. Slightly verbose on the Meta-parity justification, but every element is functional.

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 should ideally describe what a saved pack returns (e.g., its identifier for later reuse). It covers inputs well but stops short of describing the result, leaving a gap for a mutation 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 0%, so the description must carry the burden and largely does: it documents advertiser_id, name, and the adgroup_id/adset_id alias equivalence, plus a worked example. Only connection_context is left undocumented, a small residual gap.

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+resource: fetch one live TikTok adgroup's interest targeting and save it as a reusable pack. It is clearly distinguishable from siblings like interests_fetch_from_adset, interests_archive, interests_get, and interests_list.

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 names the alternative (interests_fetch_from_adset) and the condition that selects this tool — matching the Meta two-step flow so portable agent code stays identical. That is a clear when/when-not routing statement.

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