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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, and the description reinforces that with 'Read-only: nothing is ever changed in Meta.' It also adds useful unit conventions for amounts and rates, but does not discuss auth requirements, rate limits, pagination, or ordering, so it adds only moderate behavioral context.

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 description is front-loaded with the core action and then efficiently lists the returned fields, unit conventions, and read-only behavior. It is dense but largely earns its length because there is no output schema to document the return values.

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 does substantial work by enumerating the returned ad metrics, units, and read-only nature. It is nearly complete for calling the tool, though it omits details such as result ordering or pagination behavior.

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 all four parameters including the range enum are documented in the input schema. The description itself adds no parameter-specific meaning, so the baseline of 3 is appropriate.

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 that this tool lists every Meta ad and enumerates the ad-level metrics returned, so an agent can understand the core operation. It does not explicitly distinguish itself from sibling tools such as get_meta_ads_overview or get_meta_ads_breakdowns, which keeps it below a 5.

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?

Usage is implied by 'Every Meta ad with...' but the description gives no explicit guidance on when to choose this tool over alternatives like get_meta_ads_overview, get_meta_ads_breakdowns, or list_meta_ads_issues. It is minimally adequate but lacks routing guidance.

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