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

Annotations already declare readOnlyHint=false, destructiveHint=false, and openWorldHint=true, so the external-send nature is covered structurally. The description adds two useful constraints beyond the annotations: the invoice must be paid, and the address is the buyer's on-file address (not caller-supplied). It says nothing about repeat-send limits, failure modes, or whether a resend is 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?

Three sentences say essentially the same thing three times ('Re-send the receipt email to the buyer on file' / 'Emails the receipt ... again to the buyer's address on file' / 'Sends an email to the buyer'). The opening sentence is well front-loaded, but two of three sentences are pure restatement and fail to earn their place.

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 simple two-parameter tool with full schema coverage and no output schema, the description covers the core action adequately. It omits what an agent would want to know before calling: whether resending repeatedly is allowed, what happens if the invoice is unpaid, and any confirmation of effect.

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 (id, business) are already documented in the schema, and the description adds no syntax, format, or semantics beyond that. Baseline 3 applies when the schema carries the parameter burden.

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 (re-send the receipt email) and clarifies the recipient is the buyer on file, so the action is unambiguous. It does not distinguish itself from the sibling agenta_invoices_receipt, which an agent may confuse with this one.

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?

No when-to-use guidance, no preconditions, and no mention of the closely named sibling agenta_invoices_receipt as an alternative. The only signal is the name itself, which the agent must infer from.

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