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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds that this is global coverage statistics spanning supply and demand, which adds some context beyond the annotations. However, it doesn't clarify whether the results are aggregates only or include per-node breakdowns, pagination, or time-dependency.

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?

One short sentence with zero filler. It front-loads 'Global coverage statistics' and immediately enumerates the meaningful dimensions in parenthetical detail. Every word earns its place.

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?

Given that there is an output schema, zero parameters, and annotations already cover the safety profile, the description is largely complete. It conveys the global scope and the supply/demand distinction. A minor gap is not explicitly stating that this is an aggregate overview rather than a per-entity lookup, but the sibling list and output schema help fill that in.

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 tool has 0 parameters, and schema description coverage is 100%, so there are no parameter semantics for the description to add. Per calibration, 0 params with full coverage earns a baseline 4; the description's mention of 'supply' and 'demand' provides meaningful context about what the global statistics represent.

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 states a clear verb+resource ('Global coverage statistics') and enumerates the specific dimensions (GTINs, nodes, makers, retailers), which distinguishes it from sibling tools like find_makers or find_retailers. However, it doesn't explicitly differentiate it from other statistics-like tools such as node_market or list_nodes, so it stops short of a 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?

The description implies usage for global supply/demand coverage analysis and distinguishes supply vs demand roles, but it doesn't explicitly state when to use this tool versus alternatives like find_makers or find_retailers. It provides no exclusions or alternative routing, so it's adequate but not explicit.

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