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

Annotations already declare readOnlyHint=true, so safety is covered; the description still adds real context by enumerating the returned row fields (id, number, type, VS, currency, total, flags/flags_decoded with decoded meanings, public/PDF URLs) and confirming paging. It omits rate limits, auth requirements, and total-result counting behavior.

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?

One dense paragraph, front-loaded with purpose, the sibling alternative, and the high-frequency sort hint before the longer return-field enumeration. Each clause carries information, though it runs long and could be split for scanability.

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, so the description correctly carries the burden of describing the row shape (including decoded flags and URL fields) and paging. Combined with a fully documented 11-parameter schema, an agent has everything needed to call it 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 coverage is 100%, so the baseline is 3; the description adds a small amount of meaning by consolidating the filter set (q, customer id, type, number, VS, currency, creation date range) and by giving a default sort example. It does not add new syntax beyond what the schema documents for sort, type codes, or date formats.

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 (search/list) plus the resource family in local terms (faktury, zalohove faktury, proformy, objednavky) and explicitly distinguishes itself from vyfakturuj_get_invoice. An agent can tell what this tool returns without opening the schema.

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?

Routes the agent to the correct sibling: 'use vyfakturuj_get_invoice for the whole document with items', and gives a concrete usage hint ('pass sort=date_created~desc for the newest first'). No explicit when-not guidance (e.g. interaction with list_contacts or other list tools) beyond the single alternative.

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