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

Annotations only declare readOnly=false, destructive=false, openWorld=false; the description adds real behavioral context beyond that: the server reads source settings once, preserves Smart+/Spark identity semantics, keeps the new ads disabled, binds a single aggregate approval, and enforces same-advertiser scope. That materially changes how an agent plans the call.

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?

It is front-loaded with the core purpose and every sentence carries substantive information, with no filler. The single dense paragraph makes the mode-specific rules harder to scan than a short structured list would, 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 an 11-parameter mutation-style tool with no output schema, the description covers modes, constraints, side effects, and scheduling overrides well. It omits what the call returns (the handle feeding copy_ad_quick_copy_confirm/deny, despite referencing an "aggregate approval") and leaves connection_context undefined.

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 description coverage across 11 parameters, the description carries the full burden and mostly succeeds: it constrains copies to 1..10, source_ad_ids to 1..20, names copy_mode=reuse|fresh, ties creative to fresh mode, and documents execution.start_time/end_time as ISO8601. Gaps remain: append_mode's accepted values and connection_context are never explained.

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?

The description names a specific verb and resource ("Prepare a TikTok-native copy without publishing") and enumerates the two operating modes, so the agent knows exactly what the tool produces. It does not, however, differentiate itself from the close sibling copy_ad_clone_structure, which an agent could easily confuse with this one.

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?

It gives explicit invocation conditions per mode: single-source needs advertiser_id + source_ad_id with copies 1..10, grouped append needs source_ad_ids (1..20) plus a campaign or adgroup target, and "Grouped copy supports reuse only." It also supplies negative guidance ("never use Meta append-adset or client-side fan-out"), but it never routes the agent between this tool and copy_ad_clone_structure.

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