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

Annotations only declare readOnlyHint=false, openWorldHint=true and destructiveHint=false; the description adds meaningful behavioral detail beyond them — that the message goes to an external client with a portal payment link, that confirmation is on by default and toggleable, and that a Cotlet API key with app access is required. It stops short of stating delivery failures, rate limits, or whether the send is reversible.

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?

Front-loaded and readable, but the first two sentences restate each other — 'with a link to pay online' is repeated as 'with a link to the Workiz client portal' and the delivery channels are listed twice. Roughly half the text is redundant.

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 an external-send tool with no output schema, the description covers the essentials an agent needs: what is sent, how, confirmation behavior, the external-reach warning, and the auth requirement. Nothing critical is missing, though it could say what the client/tool returns or what happens on a failed send.

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%, so both the enum on 'via' (email/sms/both, default email) and the invoice_id source are already documented. The description echoes the channel options but adds no new syntax, format, or default semantics 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?

Specific verb (send) plus resource (invoice) and channels (email/text), so an agent knows exactly what the call does. However it never distinguishes itself from close siblings like workiz_send_estimate or workiz_create_invoice, leaving the routing inference to the agent.

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?

Provides confirmation guidance ('By default you confirm each call; you can switch that off') and a caution to confirm before reaching other people, which is real operational context. But it gives no when-to-use vs alternatives, no prerequisites tied to invoice state (e.g., drafted vs finalized), and no exclusion conditions.

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