Finalize an invoice

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

Annotations already declare this is a non-read-only, non-destructive, non-idempotent mutation. The description goes beyond them by naming what actually changes (number assigned, amounts frozen, payable URL exposed) and by disclosing two failure conditions: zero total or a past due date. It stops short of saying what happens on a repeated call or what permissions are needed, so a 4 rather than 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?

Two short paragraphs with the operative effects front-loaded and the blocking conditions placed last where they are easy to scan. The opening sentence restates the title verbatim and earns nothing, which is the main deduction.

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 one-parameter mutation with full annotation coverage, the definition supplies what an agent needs: the required state (draft), the observable effects, and the two conditions that cause failure. The absence of any note on the response shape is a minor gap, since there is no output schema to fall back on.

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 coverage is 100% and the single `id` parameter is fully documented as the `inv_…` identifier, so the schema carries the load. The description adds only the implicit constraint that the referenced invoice must be a draft; it gives no further detail on the id's form or accepted sources. 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?

States a specific verb and resource ("Finalize a draft invoice") and enumerates the concrete effects: it gets its number, amounts freeze, and `hosted_invoice_url` becomes a payable page. That is far more specific than the title. It does not explicitly distinguish itself from nearby siblings like void_invoice or mark_invoice_uncollectible, which is the only thing keeping it off a 5.

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 usage via preconditions -- the invoice must be a draft, have a non-zero total, and not be past due -- which tells an agent when the call will succeed. However, it never states when to choose this over update_invoice, void_invoice, or mark_invoice_uncollectible, so the alternative-selection guidance is left to inference.

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