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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so safety is covered. The description adds value beyond that: freshness (recomputed every morning over the last 14 days and inbound payments), rule provenance (backtested rules), and cost ("Free"), all of which help an agent decide whether to call it.

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 core output is front-loaded, but the first sentence is overloaded, tucking the weekly-check clause mid-list, and the provenance/marketing line ("backtested on real campaigns") adds padding. Information density is high yet the structure is harder to parse than it needs to be.

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?

With no output schema, the description carries the return-shape burden, and it does describe contents, ordering (by money at stake), cadence, and cost. For a parameterless read tool this is nearly sufficient, though it could state limits such as account coverage when none are connected.

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?

The tool takes zero parameters and schema coverage is 100%, so there is nothing for the description to clarify. Baseline 4 applies; no parameter-level claims are needed or missing.

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 specifies the exact payload: up to three ranked recommendations per ad account, one data-gap suggestion, and a weekly read-only check. That is a concrete, distinctive resource an agent can recognize. It does not, however, explicitly contrast itself with adjacent retrieval tools such as get_insights or mark_advice, so sibling differentiation is left to inference.

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?

It gives explicit trigger phrasing: "Call it when the person asks what to do today, what needs attention, or for advice," which maps user intent to invocation. There are no exclusions or named alternatives, so it stops short of full when/when-not guidance.

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