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

Annotations already cover the safety profile (readOnlyHint=true, destructiveHint=false, openWorldHint=true), so the bar is low. The description adds the underlying endpoints, but says nothing about not-found behavior, code case-sensitivity, or error responses.

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 short sentences, front-loaded with the resource and keying rule; the returned fields are listed compactly. The raw endpoint strings are arguably redundant with the tool itself, but they are brief.

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 simple read-only getter with two optional params and no output schema, the description covers retrieval modes, exclusivity, and return contents. Minor gaps remain around failure modes and whether code lookups are exact-match.

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 schema documents both fields and the baseline would be 3. The description adds the mutual-exclusivity/'exactly one' rule that the schema cannot express (no oneOf), making it materially more useful than the schema alone.

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 and resource (fetch one sales order) plus the two keying options and the fields returned (customer, items, prices, taxes, status). The singular 'One sales order' implicitly separates it from vintrace_list_sales_orders, but no sibling is named explicitly.

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 'Give exactly one' rule tells the agent not to pass both keys, which is a useful constraint, but there is no statement of when to prefer this over the list tool or what to do when the id/code is unknown. Usage is only implied by the required key.

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