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

Beyond the annotations, the description discloses important prerequisites: a claimed Last Price credential and a claimed workspace, including that self-registered sandbox keys receive a 403 until the workspace is claimed. It does not contradict the annotations and adds real operational context for an agent attempting the call.

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?

The description is short and front-loads the purpose before listing parameters and prerequisites. It is well structured, though the parameter summary partially duplicates the already-rich schema.

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 mutation tool with annotations, full schema coverage, and no output schema, the description covers the essential call requirements: purpose, required fields, optional fields, and auth/workspace prerequisites. It could say more about side effects on order totals, but nothing required for correct invocation is missing.

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 the schema already carries parameter documentation. The description restates the required fields and optional quantity/metadata defaults, but adds no new syntax, constraints, or semantics beyond what the schema provides. Baseline 3 is appropriate.

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?

The description states a specific verb and resource: add a line item to an order. It also names the required fields, making the operation easy to distinguish from create_order or update_order. It stops short of explicitly naming sibling alternatives or contrasting when to use this versus update_order.

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 by 'Add a line item to an order' and the parameter summary, but there is no explicit when-to-use/when-not-to-use guidance or comparison to siblings like update_order or list_order_lines. The prerequisites are useful, but alternative-selection guidance is absent.

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