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

With no annotations, the description carries the full burden and does disclose meaningful behavior: drafts are reported separately from finalized documents and currencies are never added together, which tells the agent exactly how the aggregation is scoped. It also flags that the call is free. It does not confirm read-only status or permission requirements, but for a no-parameter summary the key behavioral semantics are covered.

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 tight sentences, front-loaded with the core action and its outputs, with the two key aggregation rules attached immediately after. 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?

There is no output schema, so the description must convey the return shape and it does: counts by state and totals per currency. It leaves minor questions open (e.g., whether deleted or archived sales are counted, what 'sold value' includes relative to discounts), but is complete enough to call correctly.

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 takes zero parameters, so there is nothing for the description to clarify and the baseline of 4 applies. No hidden filtering inputs are implied.

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 (summarize) and resource (the sales book), then enumerates exactly what is computed: draft vs finalized document counts and total sold value per currency. This is clearly distinguishable from siblings like sale_list or sale_get, which retrieve records rather than aggregate them.

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 never says when to prefer this over sale_list or sale_get, nor any precondition for calling it. 'Free' hints that it is a cheap call, but that is a cost note, not usage guidance.

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