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

Annotations only declare write/non-destructive, and the description adds the material side effects: assignment of the next number in the series and possible automatic accounting by ABRA Flexi based on the invoice type. It also discloses the dry_run validation-only path, which is exactly the context an agent needs before a mutation.

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 tightly packed sentences, front-loaded with the WRITE marker and the resource, then side effects, then the dry_run recommendation, then prerequisite lookups. No filler.

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?

No output schema exists, and the description partially compensates by explaining that dry_run returns computed totals and validation errors. It could say a bit more about what a successful save returns (e.g. the created document code), but for a 10-parameter creation tool this is close to 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?

Schema coverage is 100%, so baseline is 3; the description adds value by naming the evidence (typ-faktury-vydane) for document_type_code and pointing to the contact lookup for customer_code, and by promoting dry_run as the recommended first call. It does not elaborate on item-level fields, but the schema already documents those fully.

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?

Uses a specific verb and resource plus the Czech evidence name (faktura-vydana) and states the line-item dimension. It is clearly distinguishable from read-side siblings like abraflexi_list_issued_invoices and abraflexi_get_issued_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?

Explicitly recommends dry_run first, states what the tool does NOT do (send, mark paid, e-mail), and routes the agent to abraflexi_list_records and abraflexi_list_contacts to obtain the required codes. Both when-to-use and how-to-resolve-prerequisites are covered.

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