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

Annotations already declare readOnlyHint=true and destructiveHint=false, and the description adds useful behavioral context by listing the returned fields (ID, name, status, lastSyncedAt) and confirming it is a read-only drill-down operation. No contradiction with annotations.

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 tightly packed sentences, each earning its place: the core action, the workflow position, and the downstream usage. No fluff or repetition.

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 simple read-only list tool, the description covers what it returns, how to filter, and how to chain results into subsequent tools. The output schema is absent, but the description names the return fields, which is sufficient for this tool's complexity.

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%, with the provider enum fully documented and campaignId already described as an optional filter referencing nevent_list_paid_campaigns. The description essentially repeats schema guidance without adding deeper parameter semantics, so it meets the baseline but does not exceed it.

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 the tool lists ad groups/ad sets for a paid ads provider, with an optional campaign filter. It explicitly differentiates from related siblings like nevent_list_paid_campaigns and nevent_list_paid_ads by naming its resource and position in the workflow.

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?

The description explicitly instructs to use this after nevent_list_paid_campaigns for drill-down, and tells the agent to feed returned adGroupId values into the ad group insights, targeting, and comparative stats tools. It does not explicitly state when not to use it in favor of a sibling, so it falls just short of a 5.

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