Search sales invoices

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

Annotations already declare readOnlyHint=true and openWorldHint=false, covering the safety profile. The description adds meaningful behavioral context beyond annotations: the default exclusion of proformas when document_type is absent, and the full-document behavior when `number` is supplied.

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?

Three short sentences, all earning their place. The main action and scope are front-loaded, followed by the two most important behavioral caveats. No filler or repetition of obvious type information.

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 read-only search tool with no required parameters and no output schema, the description provides enough orientation: search facets, the number shortcut, and the proforma default. Output expectations are largely covered by the response_format parameter schema, so the definition is complete for correct invocation.

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?

With schema description coverage around 60%, the description only partially compensates. It reiterates the `number` behavior already present in the schema and adds the proforma-default nuance for document_type. The generic mention of "customer" gives little semantic value for the three undocumented customer-related parameters.

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?

Description opens with a specific verb and resource: "Find sales documents", enumerates the document types in Bulgarian, and lists search dimensions (period, customer, type, number). This clearly distinguishes the tool from sales-oriented siblings like nula_search_bills and nula_get_invoice_pdf.

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?

Provides clear, actionable usage context: passing `number` returns a full document with lines, and omitting `document_type` excludes proformas. It does not explicitly name sibling alternatives or when-not-to-use conditions, but the sales scope plus parameter guidance makes invocation conditions clear.

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