list_expense_document_numbers

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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, covering the safety profile. The description adds that validation checks availability, implying a boolean-like result, but does not disclose return format, edge cases, or behavior beyond that. No contradiction with 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?

A single, front-loaded sentence that communicates the tool's function without any wasted words. It is appropriately concise for the simplicity of the tool.

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 one-parameter, read-only validation tool, the description is adequate but leaves ambiguity about the return format (e.g., boolean vs. list). The tool name suggests 'list' while the description says 'validate', and with no output schema, a bit more detail on the response would make this more complete.

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?

The schema provides a somewhat tautological description for the only parameter ('document number to validate'), but the tool description adds the key semantic that the validation checks 'availability'. This clarifies what 'validate' actually means, going beyond the schema's wording.

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?

The description uses the specific verb 'validate' and references document number availability, clearly stating the tool's core purpose. However, it does not mention 'expense' or distinguish this from the sibling tool list_purchase_document_numbers, so differentiation is left to the tool name.

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 provides no guidance on when to use this tool versus alternatives, nor does it reference the similar sibling list_purchase_document_numbers. The agent must infer usage context solely from the name and general validation semantics.

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