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

The description asserts a read-only nature ('Read... Does not modify advertising'), but the annotation declares readOnlyHint=false, implying the tool may alter state (e.g. a cache/sync refresh such as the 'fresh' parameter). This directly contradicts the structured behavioral metadata, which can mislead an agent.

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?

Two tight sentences with the core action front-loaded and no filler. It is efficient, though the second sentence is partly responsible for the annotation mismatch, so it is not flawless.

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 described. But with 5 parameters at 0% schema coverage and a behavioral contradiction against the annotations, the description leaves the agent without enough to invoke the tool confidently.

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 5 parameters. The description implies the reporting-window requirement ('explicit reporting period'), roughly mapping to since/until, but says nothing about brandId, campaignId, or the 'fresh' flag, which are otherwise entirely undocumented.

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 gives a specific verb+resource: 'Read a Meta advertising campaign, ad sets and ads for an explicit reporting period.' An agent can tell this retrieves campaign hierarchy data scoped to a time window. However, it does not differentiate this from siblings such as get_campaign, get_ad_performance or get_ad_breakdown, so the boundary 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?

There is no when-to-use or when-not-to-use guidance, no mention of prerequisites (e.g. needing brand/campaign IDs from list_campaigns), and no alternative tools are named. The clause 'Does not modify advertising' clarifies a property, not usage context.

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