Issue a credit note

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

With no annotations, the description carries the full burden. It discloses that the tool returns a draft that can still be revised, and that credit_note_finalize 'burns the final CN number,' which is important lifecycle context. It doesn't mention authentication requirements, rate limits, or that duplicate_ok exists, but the draft/finalize distinction is the key behavioral trait.

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 sentences, front-loaded with the core action and immediately followed by the key lifecycle detail (draft vs. finalize). Every phrase earns its place; no repetition or filler.

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?

Given the tool has 9 parameters, full schema coverage, and no output schema, the description covers the essential context: what it does, how it differs from finalize, and the draft return. It omits mention of optional parameters like issue_date, invoice_ref, and duplicate_ok, but the schema covers them fully, so the description is adequate though not exhaustive.

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 documents all parameters thoroughly. The description lists the key parameters (recipient, reason with examples, line items with quantity, unit price, tax rate, currency) but adds no semantic nuance beyond what's in the schema. Baseline 3 is appropriate when the schema does the heavy lifting.

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+resource ('Issue a credit note') and specifies it can be against an invoice or standalone. It connects to sibling tools by explicitly naming 'credit_note_finalize' and explaining the draft vs. final distinction, which is critical for distinguishing it from credit_note_update and credit_note_finalize.

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 description implies when to use this tool (when you want to create a credit note, either standalone or tied to an invoice) and clarifies the draft state, implying the finalize step is separate. However, it doesn't explicitly say when NOT to use it (e.g., for modifying an existing note, use credit_note_update) beyond the finalize contrast.

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