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

Annotations already declare readOnlyHint=true, and the description adds real context beyond that: the feed is ordered by version ascending, it has no date filter, pagination uses next_after and terminates when data is empty, and it enumerates the returned fields. The stop condition for pagination is the kind of operational detail annotations cannot express.

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?

Ordering and sync purpose come first, the exclusion second, then the payload shape and the pagination recipe. Every clause carries information; there is no filler or repetition of the title.

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?

No output schema exists, and the description compensates by listing the returned per-sale fields (id, date, invoice_number, state, customer_id, source, payments, line_items, totals). Combined with the pagination termination rule, an agent has everything needed to call and consume this 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?

Schema description coverage is 100%, so 'after', 'before', and 'page_size' are already fully documented. The description reinforces the pagination loop ('Paginate with next_after, stop when data is empty') but adds no format or constraint detail beyond the schema, and never mentions 'before'. Baseline 3 is appropriate when the schema carries the weight.

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 resource (sales) plus its ordering semantics (version order, oldest changes first) and its intended use (sync everything that changed). It explicitly carves itself out from search_sales and sales_summary with 'It has NO date filter', so an agent can distinguish it from siblings without reading either 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?

Gives explicit when-to-use ('the way to sync everything that changed') and explicit when-not-to-use with the named alternatives ('for a period use search_sales or sales_summary'). The condition selecting the alternative is fully stated, not inferred.

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