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

Goes well beyond the annotations by disclosing that the pull is bounded, that it may run from stored coverage or queue asynchronously, that it consumes the existing daily quota (a rate-limit constraint), and that it does not change ad delivery. The readOnlyHint=false is corroborated by the queueing/quota language, and the no-delivery-impact note is exactly the side-effect context an agent needs.

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 dense sentences with no filler, and the core purpose (what metrics, for what scope) is front-loaded before the workflow and quota notes. Sentence two packs several distinct facts but each earns its place.

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?

An output schema exists, so return values need not be explained, and the async task_ref workflow plus quota and delivery-safety notes cover the behavioral essentials for a pull tool. The main remaining gap is the undocumented non-breakdown parameters, which matters given 10 params at 0% schema coverage.

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 0% across 10 parameters, so the description carries the burden. It maps only the breakdowns enum values and vaguely references products and dates; it says nothing about level, ad_ids, conversion_event, connection_context, or the distinction between product_ids, product_refs, and product_names.

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: fetch named breakdown dimensions (country, placement, age, gender, OS, hourly) for selected products and dates. It also distinguishes itself from the sibling it hands off to (insights_read_breakdowns), so an agent can separate the pull stage from the read stage without opening either 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 a clear operational flow: pull returns task_ref, poll tasks_get_status, then read each dimension with insights_read_breakdowns, and notes stored coverage may be used instead of queuing a new pull. It does not say when to prefer this over the sibling insights_pull_insights, so it stops short of a full when/when-not routing rule.

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