Next invoice number

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

Annotations already declare readOnlyHint=true, idempotentHint=true, openWorldHint=false, and destructiveHint=false, so the safety profile is fully covered by structured data. The description adds only the nuance that the number is 'suggested' rather than guaranteed, and says nothing about whether the value is reserved or how it is derived. Adequate, but adds little beyond the annotations.

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?

One tight sentence that front-loads the return value and immediately illustrates the format. There is no filler or redundant restatement of the tool name.

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?

An output schema exists, so return values need not be explained, and the single required parameter is fully documented. For a trivial read-only lookup this is nearly complete; the only missing nuance is whether the returned number is reserved or merely advisory.

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% and the single 'year' parameter is fully documented in the schema, including its 2000-2100 range and an example. The description's 'INV-2026-004' example reinforces the year-to-number relationship but adds no syntax or semantics beyond what the schema already supplies. 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 exactly what is returned (the suggested next invoice number) scoped to a year, with a concrete format example ('INV-2026-004'). It is a noun phrase rather than a verb+resource, but it is unambiguous and distinguishable from invoice siblings like create_invoice, list_invoices, and get_invoice.

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 description gives no when-to-use guidance, no prerequisites, and names no alternatives. The usage (call it before creating an invoice) must be inferred entirely from the name and context. 'Suggested' hints the value is advisory, but nothing states when it should be consulted or whether it reserves the number.

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