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

With destructiveHint=true already declared, the description still adds material context: the same-BC constraint that causes rejection, the SHARE|CANCEL action values (which the schema does not enumerate), and the confirm=false preview vs confirm=true apply semantics — essential for a destructive operation. This is real value beyond the annotations.

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?

Three dense sentences with no filler; the core action and scope lead, followed by format, constraint, and confirm semantics. The heavy em-dash interruption in the first sentence slightly hurts readability but costs no information.

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?

An output schema exists so return values need no explanation. The description covers action modes, formats, the BC precondition, and dry-run vs apply, leaving only minor ambiguity (the role of advertiser_id and whether confirm=true is mandatory to commit).

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 burden and does well: it documents the comma-separated format for audience_ids and shared_advertiser_ids, names the action values, and explains confirm. Only advertiser_id (the owning account) is left unstated, which keeps it from a 5.

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 pair (shares / un-shares) and a specific resource (TikTok custom audiences), and scopes it to accounts under the same Business Center. No sibling tool in the list performs audience sharing, so an agent can identify it unambiguously.

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 a concrete use case (an agency reusing one seed list across managed advertisers) and the hard precondition that all targets must be in the same BC or TikTok rejects the call. It does not explicitly point at alternatives (e.g. list_tiktok_bc_advertisers to find valid targets), so it stops short of a 5.

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