Create draft Wave invoice

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

Annotations only establish that this is a non-read-only, non-destructive, non-idempotent, open-world write. The description adds real behavioral context beyond that: the record is created in DRAFT state and neither sent nor posted to the books until approve/send. It does not mention auth/permission requirements or what happens on duplicate invoice numbers, so it stops short of a 5.

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 dense sentences, front-loaded with the draft-state constraint, then prerequisites, then the riskiest parameter semantics. No filler and nothing repeated for its own sake.

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 an 11-parameter, 2-required creation tool with an output schema available, the description covers everything an agent needs to call it correctly: what it creates, the required inputs, where to get the ids, and the one parameter whose default behavior is easy to get wrong. Return values are left to the output schema, as intended.

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?

With schema coverage at 73%, the schema already documents most parameters, and the tax rule (omit sales_tax_ids for product defaults, pass [] for zero-rated) is largely restated from the schema. The description still adds value by tying the id parameters to their source tools (wave_list_customers, wave_list_products, wave_list_sales_taxes) and by surfacing the tax trap prominently rather than burying it in a nested schema.

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+resource (create a DRAFT invoice) and immediately bounds the scope: 'Nothing is sent and nothing is posted to the books.' This cleanly distinguishes it from the sibling wave_approve_invoice and wave_send_invoice, which it names.

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 preconditions ('Needs a customer id... and at least one line item with a product id') and routes the agent to the lookup siblings wave_list_customers and wave_list_products. The draft/approve/send sequencing makes the boundary between this tool and its alternatives unambiguous.

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