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

Annotations already declare readOnlyHint=true, so the safety profile is covered; the description adds genuinely useful behavior: default sort order, paging via total/next_start, and the distinction between company-currency (sumCelkem, zbyvaUhradit) and document-currency (*Men) money fields. It stops short of describing the default field set or result size limits.

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 dense sentences, front-loaded with purpose and ordering, then filtering scope, then return/semantics. No filler, though the money-field sentence is packed tightly enough that it reads as a glossary dump rather than prose.

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?

With no output schema, the description responsibly states what comes back (total, next_start). All 10 parameters are documented in the schema, so the burden is light; the only gap is not stating which fields are returned by default, which matters for an agent deciding whether to pass 'fields'.

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 the baseline is 3, but the description adds semantic meaning the schema lacks: the money-field name mapping and the instruction to pass 'fields' for other properties. It doesn't clarify the default field set that 'fields' overrides, which is the main remaining ambiguity.

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 specific verb and resource ('List received invoices') and disambiguates with the parenthetical 'bills from suppliers', which separates it from the sibling abraflexi_list_issued_invoices. Default ordering ('newest first by default') is stated up front.

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 when the tool applies (filtering by status, code, dates, text) but never names an alternative or an exclusion — e.g. it doesn't say to use abraflexi_get_received_invoice for a single bill or abraflexi_list_issued_invoices for outgoing invoices. Usage is inferable but not spelled out.

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