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

Annotations already declare destructiveHint=true and openWorldHint=true, but the description adds substantial context beyond them: submitted status does not imply email delivery, submission mutates invoice state, requires lineItems/details pre-set via update-invoice-draft, and may queue PEPPOL/IRAS external delivery and reporting.

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?

Five dense sentences, all front-loaded and each carrying a distinct warning (delivery semantics, state change, prerequisites, external side effects, alternatives). Slightly long but no sentence is wasted.

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 destructive, open-world write with no output schema, the description covers the state change, delivery caveats, prerequisites, external reporting, and return content (document links), leaving nothing essential unstated.

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 67%, so the schema carries most parameter meaning. The description adds the prerequisite relationship (invoice details and lineItems already set via update-invoice-draft) but does not clarify the nested invoice object or ID formats.

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 ('Submit a draft invoice and return its document links, or return existing links for a non-draft invoice') and explicitly differentiates the dual behavior. An agent can distinguish this from preview-invoice and get-invoice-document-links without opening a schema.

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?

It names both alternatives and the conditions that select them: 'Use preview-invoice to inspect a draft without submission, or get-invoice-document-links to retrieve links without submission.' It also states a hard gate: 'Confirm the user intends to submit.'

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