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

Annotations already declare destructiveHint=true and openWorldHint=true, and the description adds real context beyond them: the evaluation cadence (semi-hourly or daily), which actions are possible, and a human-in-the-loop confirmation gate specifically for the actions that increase spend or reactivate delivery. It still does not say whether the rule is created live immediately or what happens on failure/validation.

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?

Two sentences, no filler, and the most important constraint (the confirm gate) is placed last where it reads as the required precondition. Nothing is redundant with the title.

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 15-parameter destructive creation tool with no output schema, the description covers the concept and the confirmation gate but omits scope questions an agent will hit in practice: whether omitting ids applies the rule to all active objects, how account selection defaults, and what identifier comes back on success. 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?

Schema coverage is only 40% across 15 parameters, so the description must compensate and it partially does: it maps plain-language actions to the action enum (pauses/turns on/changes budget/notifies) and covers the schedule concept and confirm. It says nothing about ids, account, folder, language, time_preset, min_spent, or budget_change_pct, leaving roughly half the surface to the schema and enums alone.

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 ('Create an automated rule') plus the mechanism (checks campaigns/ad sets/ads every 30 minutes or daily) and the outcome space (pause, turn on, change budget, notify on a metric threshold). That is enough to distinguish it from the read-oriented siblings meta_rules and meta_delete_rule 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 an explicit prerequisite for the risky subset of actions: turn-on or budget-raise rules require confirm=true after the user's yes. It does not name alternatives (e.g. use meta_rules to inspect existing rules, meta_delete_rule to remove one) or say when not to create a rule, so it stops short of full routing guidance.

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