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

Annotations already flag destructiveHint=true and openWorldHint=true, but the description adds the crucial mechanic the agent cannot infer: the old ad is deleted and a new one created, and the new ad inherits the old ad's status unless overridden. That is real behavioral context beyond the annotations. It stops short of confirming what happens if the create fails after the delete.

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?

Short and front-loaded with the deprecation warning, which is the right priority. However, it mixes German and English within single sentences, which slows parsing for a tool definition consumed by an agent, and the workspace note is tacked on without a transition.

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 not be explained, but for a destructive 10-parameter replace operation the description leaves most content parameters (headlines, descriptions, final_urls, paths, keep_old) undefined despite 0% schema coverage. An agent cannot construct a valid replacement ad from this description alone.

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% across 10 parameters, so the description must compensate and largely does not. It explains only status (adding the ENABLED|PAUSED values the schema lacks) and workspace, leaving headlines, descriptions, path1, path2, final_urls, ad_group_id, ad_id and especially keep_old undocumented — and keep_old sits in tension with the stated 'old ad is removed' behavior.

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 the resource (ad) and, more usefully, what the operation actually does: removes the old ad and creates a new one — which distinguishes it from a simple field mutation. The deprecation notice and pointer to ads_replace_ad are front-loaded. It loses a point only because the verb 'update' understates the replace semantics that the description then has to correct.

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 says DEPRECATED — use ads_replace_ad, which is exactly the alternative-routing an agent needs and is reinforced by ads_replace_ad appearing in the sibling list. It does not, however, mention ads_update_ad_status for the status-only case, even though status override is discussed in the same sentence.

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