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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false, so the safety profile is clear. The description adds behavioral detail about output granularity (one row per app) and the comparison to the preceding equal-length window, which is not evident from schema alone. However, it does not cover potential edge cases like empty results or behavior when no tracked apps exist.

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 compact and well-structured: one sentence for output shape, one sentence for usage, and one example. Every sentence carries meaning; no filler.

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?

The tool has a full output schema and strong annotations, so the description doesn't need to explain return schema. It adequately covers the main use case and points to sibling for deeper analysis. However, the lack of parameter semantics is a gap in overall completeness, and the description could explicitly state that countries/platforms are optional filters to fully complete the picture.

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 coverage is 0% — no parameter descriptions are provided. The description only alludes to a date window ('over the last 7 days') and mentions countries as a metric, but does not explain that countries, platforms, end, and rangeDays are optional filters for the summary. With zero schema coverage, the description should compensate by explaining parameter roles, but it does not, leaving the agent to infer from names.

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 the tool returns one row per tracked app with specific metrics (countries charted, top 5/25 placements, change vs prior window, best position). It also explicitly contrasts with sibling tool get_app_country_ranks, differentiating portfolio-level summary from per-app drill-down.

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 explicit usage guidance: 'Use this for "how is my portfolio doing", then get_app_country_ranks to drill into one app.' It also provides an example question ('How did my apps do over the last 7 days?') that clarifies appropriate invocation.

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