invoices_email_history

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

Annotations already declare readOnlyHint, idempotentHint, and non-destructive behavior, so the safety profile is covered. The description still earns credit by disclosing what the response contains — delivery status, open/click tracking, bounce info, and sender identity — which annotations do not convey and which matters for an audit use case.

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?

Two sentences, no filler: the first front-loads what is returned, the second gives the use case. Nothing is repeated from the schema or annotations.

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?

With no output schema, the field enumeration is the right compensation and makes the tool callable with confidence. Minor gaps remain: no mention of whether history is paginated or bounded, and no statement that this only reads existing emails rather than triggering new ones.

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% (uuid = Invoice UUID, companyId = Company UUID override with active-company fallback), so the schema carries parameter meaning. The description adds nothing about the identifiers and does not explain the company-override behavior in prose, leaving it at the 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 ('Get the complete history of emails sent for an invoice') and enumerates the payload contents, so an agent can tell it apart from the mutating invoices_email sibling. It stops short of naming invoices_email or delivery_notes_email_history as the contrasting alternative, so differentiation is inferable rather than explicit.

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 second sentence gives intended scenarios ('audit trails', 'verifying client received the invoice'), which implies when to reach for it. There is no explicit when-not guidance or pointer to the sibling that actually sends mail (invoices_email) or to defaults configuration.

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