Send a drafted invoice to its client (moves it to sent and emails it).
Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.
{
"id": 1,
"jsonrpc": "2.0",
"method": "tools/call",
"params": {
"arguments": {
"invoice_id": "<invoice_id>"
},
"name": "send_invoice"
}
}| Name | Required | Description | Default |
|---|---|---|---|
| invoice_id | Yes | The invoice's id. |
Changes observed during successful MCP inspections.
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description carries the full burden; it does disclose the two most important behaviors — the status transition to sent and the outbound email to the client — which is meaningful for a mutation tool. It does not say whether the action is reversible, what happens if the email fails, or whether repeat calls are idempotent.
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?
A single well-formed sentence with the action front-loaded and the parenthetical carrying the two key side effects. Nothing is wasted, though the parenthetical could have been used to flag irreversibility instead of restating the state change.
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 no annotations and no output schema, the description covers the essential what-happens but leaves gaps an agent would care about: failure modes, reversibility, and how its result differs from a plain status update. Adequate as a minimum viable definition, not complete.
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% for the single invoice_id parameter, so the schema already documents the input; the description contributes only the implication that the id must reference an invoice in drafted state. No additional format or sourcing guidance is given beyond the schema baseline.
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 ("Send a drafted invoice to its client") and adds the two consequences of the action. An agent can distinguish it from a generic send or a chase, though the description does not explicitly contrast it with the sibling approve_and_send, which sounds adjacent.
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?
Usage is only implied via the qualifier "drafted", which hints the invoice must already exist in draft state before this tool is appropriate. There is no explicit when-not guidance, no statement about alternatives such as approve_and_send or chase_invoice, and no mention of prerequisites or authorization.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
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