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

Annotations already declare destructiveHint=true, idempotentHint=true, and readOnlyHint=false, so the safety profile is covered. The description adds genuinely non-structured context: the required purchase_orders:write scope and the business rule that blocks deletion of lines with received stock, which an agent cannot infer from annotations or schema.

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?

Three short sentences, front-loaded with the action, then the auth requirement, then the refusal condition. No filler, and the most decision-relevant constraint is not buried.

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 single-parameter destructive delete with annotations covering safety and no output schema, the description supplies the two things structured data lacks: the required scope and the blocking precondition. Return/error shape is unspecified, but that is minor given the delete semantics.

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?

Only one parameter (id) with 100% schema description coverage, so the schema already fully documents it. The description adds nothing about the id beyond implying which entity it identifies; the baseline 3 applies when the schema carries the parameter burden.

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?

Specific verb ('Delete') plus precise resource ('a purchase order line item'), which cleanly separates it from update_purchase_order_line, delete_purchase_order, and delete_purchase_order_link. An agent can identify the target entity and operation without opening the 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?

States a concrete precondition for successful use: lines with stock received are refused until quantity_received is reset to 0. It does not name a preferred alternative tool or explicitly route away from update_purchase_order_line, but the operational when-to-use constraint is clear.

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