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

Annotations already declare readOnlyHint=false and destructiveHint=true, so the mutation risk is covered. The description adds genuinely new behavioral facts: per-id read-after-write verification of the outcome and the batch cap of 25. It omits any mention of the preview/confirm_id write gate, which is the most safety-relevant behavior for this tool.

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?

Densely packed and front-loaded: purpose, single form, batch form, limit, verification, exclusion — each in its own short clause with no filler. The all-caps emphasis is slightly heavy but the information ordering is correct.

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 destructive batch mutation with no output schema and 43% schema coverage, the description covers the core write semantics but leaves out the confirm_id two-step flow and the account_id/profile_id targeting context. An agent could call it correctly in the common case but would miss prerequisite mechanics.

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 43%, so the description must compensate: it does well for campaign_id, daily_budget, state and the items[] shape. However account_id and profile_id are not explained in the description (account_id is partly covered by the schema, profile_id nowhere), leaving a real gap for a 7-parameter tool.

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?

Specific verb+resource ('Aggiorna ... campagne Sponsored Display ESISTENTI') with explicit scope: budget and/or state only. It distinguishes single vs batch forms and explicitly negates creation ('NON crea campagne SD'), which cleanly separates it from ads_create_sp_campaign and from ads_update_sd_ad_group.

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?

Tells the agent the two calling modes (SINGOLA: campaign_id + daily_budget/state; BATCH: items[] with MAX 25) and that only existing campaigns are targeted. It stops short of naming an alternative sibling or stating exclusion conditions beyond 'does not create', so it is strong context rather than full when/when-not routing.

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