peek_invoice_number

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

No annotations are provided, so the description carries the full burden. It does disclose the single most important trait — that nothing is reserved and the counter is not advanced — but omits whether the number could change before issuance, any permission requirements, or side effects. Adequate but not complete for an unannotated tool.

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 compact sentence with no waste, and the non-reserving caveat is placed immediately after the purpose. It is arguably terse enough to leave gaps, but nothing is redundant.

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?

A one-optional-parameter read tool with an output schema, so return values need not be explained. The description covers purpose and the non-reserving guarantee; only explicit guidance on its relationship to issue_invoice is missing.

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%, with issue_date documented as YYYY-MM-DD defaulting to today. The description adds nothing about the parameter, which is acceptable given the schema already covers it, but it does not explain how the date affects the returned number.

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 concrete resource and action: returns the next invoice number according to the records. The parenthetical '(nic nerezervuje)' distinguishes it from the write-side siblings such as issue_invoice, though the name itself carries much of that load.

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 non-reserving note implies a preview/peek use case, but the description never explicitly says when to call this instead of issue_invoice or how the result should be used. The distinction is implied rather than stated.

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