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

Annotations already declare this as read-only, idempotent, and non-destructive. The description adds substantive behavioral context beyond annotations by specifying what the report includes (portfolio summary, needs attention, wins, competitor movements, new entrants) and noting that it is the same analysis as the email report. This gives the agent a clear picture of the tool's output without needing to inspect the output schema.

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 two sentences plus an example question. It is front-loaded with the core content, then gives the use case, then provides a concrete query example. Every sentence adds value, and the structure is efficient and highly scannable.

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 simple read-only tool with one optional parameter and an output schema, the description covers the report contents, the intended use case, and an example. It does not explicitly explain when to use 'weekly' vs 'daily', but the title and schema provide enough. The output schema likely covers return structure, so no further detail is needed.

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 input schema has one parameter 'frequency' with enum ['daily','weekly'] and default 'daily'. Schema description coverage is 0%, so the description must compensate, but it does not explicitly explain the frequency parameter. However, the tool title mentions 'daily or weekly report' and the description's overnight context implies daily usage, which helps. The parameter is simple and self-explanatory from the schema, so the lack of description is not a major gap.

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 what the tool does: it provides the same analysis used for the user's email report, enumerating specific components (portfolio summary, needs attention, wins, competitor movements, new entrants). It also differentiates itself from siblings by positioning it as 'the best single call' for a scheduled overnight digest, making its scope distinct from more specific tools like get_app_country_ranks or get_app_history.

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 description gives a clear usage context: it is intended for a scheduled 'what happened overnight' digest, and the example question 'What happened with my apps overnight?' reinforces when to call it. It does not explicitly exclude other tools or mention alternatives, but the context is strong enough to guide selection.

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