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

With annotations only saying readOnlyHint=false and destructiveHint=false, the description adds genuinely useful context: it persists a plan but does not modify advertising entities, and the plan is immutable. It does not state plan lifetime, what confirmation consumes it, or any failure/rate-limit behavior, which keeps it from a 5.

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?

Three short sentences, front-loaded with the plan concept and no filler. The middle sentence 'Creates advertising ad groups' slightly risks being read as immediate execution, requiring the third sentence to disambiguate.

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?

Complete for a plan-preparation tool: schema is exhaustive and an output schema exists, so return values need no explanation. The one remaining gap is that the description never points to the confirming tool or describes the confirm step the plan is prepared for.

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 100% and the nested adGroups/defaultBid/automaticTargetBidding semantics are already documented in the schema. The description restates defaultBid and server-side adProduct resolution, adding little beyond what the schema provides, so the baseline 3 applies.

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 states a specific verb and resource ('Prepares an immutable, separately confirmable Amazon Ads plan. Creates advertising ad groups') and clarifies the scope boundary by saying it persists an internal plan without changing advertising entities. It implicitly contrasts with the apply_ad_group_creation sibling, though it never names it.

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?

'Separately confirmable' implies a prepare-then-confirm workflow, but the description never says explicitly to use this instead of apply_ad_group_creation or that a follow-up confirmation step is required. The selection logic must be inferred from sibling names alone.

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