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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=true, so the safety profile is covered. The description adds that period performance is included and that results can be scoped by campaign, which is useful beyond the annotations. It says nothing about result volume, pagination, or the summary/full toggle's effect on shape, so it adds only modest 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?

Two short sentences, front-loaded with what the tool returns, then the scoping hint. No filler or repetition. It is nearly minimal, though the second sentence is fragmentary enough that the relationship between 'filter by campaign' and the other optional filters is left implied.

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 9 optional parameters, no required inputs and no output schema, the description earns credit for enumerating returned fields, which compensates for the missing output schema. It omits the default date window, whether results are all ad sets or only top rows under 'summary' detail, and any sense of result size. Adequate but with real gaps for a zero-required-parameter listing tool.

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 89%, so the input schema already explains detail, folder, account, campaign, date_range, language and the start/end pair in detail. The description only echoes the campaign filter and does not clarify interactions such as date_range versus start_date/end_date. Baseline 3 applies when the schema carries the semantics.

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 names a concrete resource (ad sets) and enumerates the data it carries — status, optimisation goal, budget, bid, schedule, targeting summary, period performance. That is far more specific than restating the title. It does not, however, contrast itself with meta_campaigns or meta_ads, so an agent must infer the hierarchy split from the name alone.

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 only usage signal is 'Filter by campaign', which is a parameter hint rather than a when-to-use rule. There is no guidance on when to prefer this over meta_ads, meta_performance or meta_campaigns, and no stated prerequisites or exclusions despite many adjacent siblings.

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