Get invoice

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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint, so the safety profile is covered. The description adds genuine value by disclosing the exact contents of the response (payments with date, amount, method, status; retainage; balance due in dollars), which matters because there is no output schema. It omits error behavior for an invalid/missing invoice_id.

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, front-loaded with the resource and its scope. The second sentence largely restates the first's field list with more detail, so there is mild redundancy, but no filler.

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 description carries the return-value burden and does so thoroughly. What's missing is minor: behavior on a nonexistent invoice and any permission/scope requirements.

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?

Only one parameter and schema coverage is 100% – the schema itself says 'From list_invoices.' The description adds no format or constraint detail for invoice_id, so 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 a specific verb (get) and resource (invoice) and enumerates the payload: status, project, customer, dates, terms, retainage, totals, line items, payments. An agent can tell it returns a single fully-hydrated invoice rather than a list, though the description never names list_invoices as the contrasting sibling.

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 or when-not-to-use guidance, and no explanation of the relationship to list_invoices or update_invoice. Usage is only inferable from the name and the detailed field list; the only routing hint ('From list_invoices') lives in the schema, not the description.

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