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

Annotations already mark the tool as non-read-only and non-destructive; the description adds meaningful behavior beyond that: budgets are in cents, campaign budget optimization means ad sets must not carry their own budgets, leaving the campaign budget empty switches to per-ad-set budgeting, and bulk execution is supported. It doesn't disclose auth needs or response shape, but the added context is substantive.

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?

The description is structured with actions, objectives, budget rules, a delete pointer, and a bulk-support note. It is front-loaded and mostly efficient, though the 'Flattened action: update' line is cryptic and could be clarified or removed.

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 complex 11-parameter write tool with no output schema and minimal annotations, the description covers core actions, budget semantics, objectives, and bulk support. However, it omits several parameter behaviors (daily vs lifetime budget, bid_strategy, special_ad_categories) and return/response expectations, making it adequate but with clear gaps.

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, the description compensates for core parameters: name, objective, budget (in cents), status/pause/activate, and campaign_ids. However, it leaves daily_budget vs lifetime_budget, bid_strategy, special_ad_categories, and account/auth_account unexplained, so it only partially covers the 11-parameter surface.

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 clearly states it creates, updates, pauses, or activates Meta Ads campaigns and names concrete actions. It explicitly routes destructive deletion to a sibling tool, but it doesn't differentiate from the sibling create/pause/activate tools, and the 'Flattened action: update' note muddies the actual scope.

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?

Provides some usage guidance: it says delete should go to meta_ads_campaign_delete, explains the campaign-budget-optimization constraint, and notes bulk execution via campaign_ids. However, it never clarifies when to prefer this tool over the sibling meta_ads_campaign_write_create, meta_ads_campaign_write_pause, or meta_ads_campaign_write_activate tools, leaving overlap unresolved.

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