Download a sales or finance report

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

Annotations already cover the safety profile (readOnly, idempotent, openWorld, non-destructive), so the description adds value beyond that by disclosing the raw return format (gzipped TSV), what parsed output the caller gets (row count, columns, simple totals, first rows), and the auth/role requirement. It stops short of noting rate limits or failure modes, keeping it at 4.

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 sentences, no filler. Behavior and output shape are front-loaded, and the credential prerequisites follow. Every clause carries information an agent needs.

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?

There is no output schema, so the description carries the burden of explaining returns, and it does so adequately (row count, columns, totals, first rows). Combined with the disclosed auth requirements and format, an agent has what it needs to invoke correctly; only failure/error semantics are omitted.

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?

With 60% schema coverage, the schema already documents most parameters (rows, save_to, version, region_code, report_date, report_type). The description adds meaning the schema lacks: vendor_number may be supplied directly or via the ASC_VENDOR_NUMBER environment variable, and where to obtain it, which is genuinely useful for the only required-adjacent auth parameter.

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?

States a specific verb+resource ("Downloads a sales or finance report"), names the source format (Apple gzipped TSV), and clarifies the dual behavior (optional save plus parsed summary output). No sibling tool downloads reports, so it is unambiguously distinguishable from list_apps/get_reviews/etc.

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?

Gives concrete prerequisites for use: the vendor number must come from App Store Connect > Payments and Financial Reports, and a key with the Finance or Sales role is required. There is no explicit when-not-to-use clause or named alternative, but no sibling competes for this task, so the context is sufficient.

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