beel_get_recurring_next_occurrence

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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds critical behavioral detail: 'Nothing is persisted and no numbering is consumed' and 'computed from the current issuer, recipient and series data.' It also flags fiscal guardrails that must be read before calling. This goes beyond annotations to clarify side-effect-free semantics. No contradiction.

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?

The description is well-structured with a clear opening statement of purpose, an endpoint line, and a bulleted list of guardrails. It is efficient and front-loaded with the key behavior. The endpoint line is arguably redundant (tool name and schema imply it) but not harmful. The overall structure is clean and readable.

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?

Given the tool's complexity—fiscal implications and no output schema—the description covers the essential behavior (preview, no side effects) and points to guardrail resources and beel_docs_search for exhaustive rules. It does not describe the return format or error scenarios, but these are not critical for a read-only preview with no output schema. It sufficiently equips an agent to call correctly.

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 50%: company_id has a detailed description, but recurring_invoice_id has none. The tool description does not compensate—it only refers to 'this recurring template' generically and does not explain what recurring_invoice_id identifies. Since the description fails to add meaning for the undocumented parameter, the score is low.

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 clearly states the tool returns the invoice that would be produced by the next generation of a recurring template, computed from current data, and explicitly notes that nothing is persisted and no numbering is consumed. This distinguishes it from sibling tools like beel_generate_recurring_invoice_now, which would actually generate, and from beel_get_recurring_invoice which retrieves existing invoices. The verb 'Returns' and specific resource make the purpose unambiguous.

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 implies the tool is for previewing (no persistence, no numbering consumed) but does not explicitly state when to use it versus alternatives like beel_generate_recurring_invoice_now or when to avoid it. It mentions guardrails and points to beel_docs_search for exhaustive rules, but lacks explicit when/when-not or alternative comparison. The usage context is clear enough to infer, but not explicitly guided.

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