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

With no annotations, the description carries the behavioral burden itself: it establishes a read operation, discloses the fixed channel_pid, explains delegation to the Meta-owned MMP service, and says completeness/source-coverage fields are preserved. It stops short of describing response shape or auth/rate limits, but the main side-effect and scoping behaviors are covered.

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?

Every sentence earns its place: scope, server behavior, constraints, required/optional parameters, and a full example. The REQUIRED/EXAMPLE formatting makes critical invocation details scannable without bloating the description.

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?

For a five-parameter read tool with no output schema, the description provides enough to invoke correctly: parameters, date format, breakdown enum, range limits, and an example. It omits lower-stakes context such as error cases and response-level details, but the returned aggregate types are already named.

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%, and the description compensates thoroughly: it lists required parameters, specifies YYYY-MM-DD dates, enumerates the optional breakdown choices, explains that adset maps to TikTok's native ad_group role, and adds the inclusive at-most-90-day constraint. The example also demonstrates exact invocation syntax.

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 opens with a specific verb and resource: 'Read AppsFlyer count, unique-user, and revenue aggregates for one saved product/event over an inclusive range of at most 90 days.' It also distinguishes scope by noting the server fixes channel_pid=tiktokglobal_int and instructing not to fan out by date or channel.

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 clearly frames intended use: a single saved product/event summary with a max 90-day range, required parameters, and an explicit 'do not fan out' constraint. It doesn't name sibling alternatives, but the stated constraints are enough to route an agent to this tool.

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