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

Annotations already flag this as non-read-only and open-world, but the description adds genuinely useful context beyond them: it reaches other people, so confirmation before each call is advised, per-call confirmation can be toggled off, and a scoped Cotlet API key is required. That is real behavioral disclosure.

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 core operation is front-loaded, which is good, but the second sentence largely restates the first ('Approve the invoice and email it to the customer, with payment reminders if enabled' vs. 'Approves a draft invoice and emails it to the customer, with payment reminders if you enabled them'). The duplication wastes space.

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 mutation/send tool with no output schema, the description covers the key operational facts an agent needs: approval semantics, external visibility, confirmation expectation, and auth requirements. It stops short of downstream consequences such as whether the invoice becomes non-editable after approval.

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 invoice_id, message, and send_me_a_copy are already documented with defaults. The description restates the template default for the email text but adds no syntax, format, or edge-case detail beyond the schema, so the baseline 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?

States specific verbs (approve, email) and the resource (invoice), plus the side effects (payment reminders, template-driven email text). An agent can distinguish this from tradify_send_quote or tradify_list_invoices without opening any 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?

The description implies when to use it (approving a draft invoice and sending it to the customer) but gives no explicit exclusions or alternative routing, e.g. no guidance on send vs. create_invoice_from_quote or on drafts that should not be approved. Usage is inferable rather than stated.

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