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

Annotations declare readOnlyHint=false, destructiveHint=false and openWorldHint=false, so safety is partly covered. The description's use of 'Prepare' usefully signals that the copy is not committed by this call, adding context beyond the annotations, but it omits what gets staged, whether source ad settings (headlines/URLs/descriptions) are carried over, and what the caller receives.

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?

A single front-loaded sentence with no wasted words; the resource and target are stated immediately. It is efficient, though so terse that it under-specifies relative to the tool's 7-parameter surface.

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 7-parameter, no-output-schema mutation-staging tool with undocumented params, one sentence is inadequate. There is no explanation of the prepare/confirm workflow, where the resulting plan/task id comes from, or how the optional override arrays interact with the source ad.

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 coverage is only 14% (just customer_id documented) across 7 parameters, so the description must compensate and does not. It says nothing about source_ad_id, target_ad_group_id, or the optional headline/final_url/description override arrays, leaving their role completely unexplained.

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 and resource: 'Prepare copying a responsive search ad into a target ad group.' Combined with the sibling google_ads_copy_ad_confirm, an agent can infer the two-phase staging pattern. It does not explicitly name the confirm sibling or explain what 'prepare' returns, so it stops short of a 5.

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?

No when-to-use guidance and no mention of alternatives. Critically, it never says this is the first half of a prepare/confirm pair that must be followed by google_ads_copy_ad_confirm, which is the single most important usage fact for a 'prepare' tool in this family.

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