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

readOnlyHint=true already tells the agent this is a safe read, so the bar is lower. The only behavioral detail added is the at-most-6-months period cap, which is already stated verbatim in the date_to schema description, so it adds little beyond structured data. Nothing about return shape, report granularity, or rate limits.

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 compact sentences with the substantive content front-loaded. The trailing 'Printful: GET /reports/statistics' restates the operation without adding decision-relevant information, a minor bit of waste rather than a problem.

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 read-only reporting endpoint with 5/5 parameters fully described and an enum-constrained report_types list, the description covers what the agent needs to invoke it. With no output schema, some note on what the reports contain (aggregate totals vs. per-order rows) would help, but it is not essential.

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 currency, store_id, date_from/date_to and the report_types enum are all fully documented in the schema. The description adds no syntax, default, or format detail beyond what the schema provides, which is the correct baseline of 3 when the schema carries the load.

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?

Names the resource (statistics reports) and enumerates the content categories returned: sales, costs, profit and order counts, scoped to a period. An agent can distinguish it from cost-estimation siblings like printful_estimate_order_costs. It stops short of explicitly contrasting with any sibling tool, so a 4 rather than 5.

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?

Usage is only implied: 'reports for a period' suggests historical/aggregate analysis rather than order-level lookups. It gives no when-to-use versus printful_estimate_order_costs or printful_list_orders, and no prerequisites (e.g. token type). The 6-month limit is a constraint, not routing guidance.

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