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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=true, so the safety profile is covered. The description adds useful context about what a call returns (header fields, line items), but says nothing about permissions, rate limits, or the behavior of the sparse-field selector.

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?

A single front-loaded sentence that names the resource, scope, and returned content, followed by a short endpoint reference. Tight overall, though the raw GET path is partly redundant with 'by id' and the enumerated field list is dense.

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?

With no output schema, the description carries the return-value burden and does so by listing header fields and line items, which is adequate for a read tool. The remaining gap is the undocumented `fields` selector behavior, which the agent cannot infer from schema or description.

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 only 50%: purchase_order_id carries a description while the `fields` parameter has none anywhere. The description's 'by id' merely restates the required parameter and does not explain that `fields` is a sparse-fieldset selector (pattern/maxLength of 2000), so it fails to compensate for the coverage gap.

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 (get) plus resource (one purchase order, transfer or assembly order by id) and enumerates the payload contents (header fields and line items). 'One ... by id' implicitly but clearly separates it from the sibling list_purchase_orders, and the scoping to a single document separates it from the connection/stock-update siblings.

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 implied rather than stated: 'by id' tells the agent a purchase_order_id is required, which implies you must already know the id (likely from list_purchase_orders). There is no explicit when-to-use, when-not-to-use, or named alternative for fetching related resources like connections or stock updates.

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