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

Beyond the annotations (readOnly=false, destructive=false, openWorld=true), the description discloses what is copied (lines, totals, attached details), the quote status change to Converted, the guard on non-approved quotes, that the invoice is not sent, the per-call confirmation behavior, that it 'reaches other people', and the required API key scope. Rich behavioral context.

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 leads with the core action and side effects, then layers preconditions and alternatives. It is somewhat long and repeats the core action ('Turn an approved quote into an invoice' / 'Creates an invoice from a quote'), but nearly every sentence adds non-redundant information.

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 two-parameter mutation with no output schema, the description covers preconditions, side effects, error behavior (returns quote status), confirmation requirements, and auth needs. Nothing an agent needs to call it correctly is missing.

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 both parameters (company, quote_number) are already well documented, including where quote_number comes from. The description adds no additional parameter syntax or format detail beyond the schema, so the baseline of 3 applies.

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 names a specific verb and resource ('Turn an approved quote into an invoice') and immediately explains the side effects (creates invoice, links the two, marks quote Converted). This clearly distinguishes it from siblings like create_invoice or send_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?

It explicitly states when to use it (approved quotes not auto-converted by Invoice Ninja's own workflow setting), what happens if the precondition fails (call stops and returns the status), and names the alternative for sending (send_invoice). This is about as complete as usage guidance gets.

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