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

Annotations indicate a non-read-only, non-destructive operation, and the description aligns with that by saying 'Create a draft invoice.' It adds useful context beyond the annotations: the invoice starts with one line item using the deal's amount, and client_name defaults from the deal's company/title. However, it does not disclose potential side effects on the deal (e.g., marking it as invoiced) or clarify how tax_rate, due_date, and other options affect the invoice.

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 two concise sentences that front-load the core action and the most important default. Every word earns its place with no redundancy 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?

The description conveys the essential purpose and a key default, but for a 7-parameter tool with low schema coverage, it leaves significant gaps: it does not explain most parameters, prerequisites (e.g., the deal must exist and be owned by the caller), or edge cases (e.g., repeated calls creating multiple drafts). Since an output schema exists, return values are covered elsewhere, but the overall package is only minimally viable.

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 29%, so the tool description must compensate for the undocumented parameters. It only clarifies deal_id (required) and client_name (defaulted from the deal), leaving notes, due_date, tax_rate, client_email, and payment_terms unexplained. This is insufficient for reliable parameter selection and usage.

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 clearly states a specific verb ('Create') and resource ('a draft invoice from one of the caller's deals'), making the tool's purpose distinct. It also specifies a key behavior ('one line item for the deal's amount') and a default behavior for client_name, which differentiates it from generic invoice creation tools like create_invoice.

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 the tool—when you want to create a draft invoice from a specific deal—by emphasizing deal_id is required. However, it provides no explicit exclusions or alternatives, such as noting that create_invoice is intended for blank invoices or that add_invoice_line_item handles additional line items. This lack of comparative guidance is a gap.

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