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

Annotations only say read-only/non-destructive/non-open-world, and the description adds substantial behavior the agent could not infer: async IN_PROGRESS handling with retry_after_seconds, that CANCELLED means no Amazon EPR data rather than no obligations, data-quality flags returned, and that registration numbers are read-back-only and manually entered in Seller Central.

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?

Front-loaded warning (READ-ONLY) and resource, followed by returns, usage, and operational caveats in a logical order; dense but nearly every sentence carries non-redundant information, though the run-on enumeration of return fields is heavy.

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 no output schema, the description fully compensates by listing returned dimensions (units, total and material weights, period start/end, quality flags, top ASINs) and covering the async/cancellation lifecycle and the manual-registration boundary.

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 100%, so the baseline is 3, but the description reinforces the closed-period constraint ('current/future periods are rejected', 'Default: last closed month') and clarifies that limit only controls top-ASIN listing while summaries always cover all rows.

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 (read an Amazon EPR report for one seller outpost and one closed period), names the underlying SP-API endpoints, and enumerates the exact returned metrics. An agent can distinguish it from sibling compliance/audit tools (audit_compliance) without opening a schema.

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?

Explicitly says what it is for ('prepare or check an EPR declaration... for a consultant or producer compliance scheme') and what it is not ('support data, not a legal certification'), plus a clear when-not: EPR registration numbers cannot be uploaded or changed via any API. It does not name an alternative sibling tool, so it stops short of a 5.

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