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

Annotations already declare readOnlyHint and openWorldHint=false, and the description adds real behavior: results are newest-first, open drafts are included, credit notes appear alongside invoices, and voided/written_off statuses exist. It omits result limits and whether credit notes affect totals.

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 scope and ordering, then the returned-field list, then usage. The status enumeration is long but each item earns its place by telling the agent what it can filter/expect.

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 compensates well by describing the returned fields. Remaining gaps are minor: no result volume/pagination guidance and no note on whether open drafts are unfiltered by period.

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% with a self-describing enum and a documented default, so the schema already carries the parameter meaning. The description only says "in a period" and adds no semantics beyond the enum itself.

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 (query) and resource (invoices) scoped to a period, and enumerates the returned fields including status, type and credit-note linkage. It implicitly separates itself from query_open_invoices by noting it also returns paid/cancelled invoices, but never names the sibling explicitly.

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?

"Use for questions about specific invoices, paid or cancelled ones, or credit notes" gives clear selection context, which contrasts with the open-invoices-only sibling. No explicit exclusions or named alternatives, so it stops short of the top band.

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