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

Annotations only declare the mutation safety profile (readOnlyHint=false, destructiveHint=false, idempotentHint=false), so the description usefully adds the return contract ({integrationId, action, status, kind, editUrl, message} with integrationId belonging to the NEW clone) and the project_id_required failure mode. It does not say whether items, submissions or item-level state are copied, which is the main behavioral unknown for a clone operation.

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?

Front-loaded with the action, then rationale, then domain clarification, then return shape and parameter notes — a sensible funnel. The ads-versus-marketplaces sentence and the inline return-payload literal are dense but each earns its place by preventing sibling confusion and substituting for the missing output schema.

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 two-parameter mutation with no output schema and no annotation coverage of returns, the definition supplies return fields, status semantics, and the project_id prerequisite, which is close to fully self-contained. The remaining gap is whether the clone carries over items or only the ad's settings and configuration, which materially affects how an agent should follow up.

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 has to compensate and it largely does: ad_id is identified as the source ad obtained from list_ads, and project_id is explained as optional with an explicit inference rule and fallback path. It does not add anything about value constraints beyond what the schema's integer/exclusiveMinimum already conveys.

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 ('Clone an ad — create a copy of it (settings and configuration) as a new ad') and clarifies the domain object ('Ads are product-listing channels ... not marketplaces'), which separates it from the sibling clone_marketplace. An agent can distinguish this from clone_marketplace, create_ad, and repair_ad without opening any schema.

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 clear usage statement ('Use this to copy an ad configuration to a new ad') plus a prerequisite chain: get ad_id from list_ads, and only supply project_id when required, otherwise call list_projects. It never states when NOT to clone (e.g. versus create_ad from scratch), but the context is otherwise unambiguous.

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