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

Beyond the annotations it discloses the most important trait: nothing is transmitted, only a draft XML is prepared, saved and must be sent separately from the dashboard after user review. It also mentions XSD validation against the Czech financial administration schema and that includePending=false is the default. It does not state idempotency (what happens if the same period is generated twice) or whether an existing filing is overwritten.

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 core purpose and the non-sending caveat are front-loaded, and the remaining sentences carry operative rules rather than filler. It is dense with long parentheticals, so an agent must parse several clauses, but no sentence is purely 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?

There is no output schema, and the description compensates by describing the return payload: summary (tax liability or overpayment, return lines, KH sections, deadline), errors and warnings, and an XML download link. For an 8-parameter generation tool with a nuanced period model, the definition is complete enough 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 coverage is 100%, so the schema already carries each parameter's meaning; the description still adds real value by explaining the monthly-vs-quarterly conditional logic, the companyId default (main VAT-registered company, id from list_companies) and that includePending defaults to approved documents only. The okec and cisloUfo parameters are not elaborated on in prose, but their schema descriptions cover them.

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 opens with a specific verb and resource ("Vygeneruje NAVRH XML podani DPH") and enumerates the three exact submissions produced, each mapping to a submissionType enum value (DPHDP3/DPHKH1/DPHSHV). It also explicitly separates this from sending ("Podani se NIKAM neodesila ... odeslani probiha vyhradne v dashboardu"), which distinguishes it from sibling submit_vat_filing.

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?

It states the selection rule for the two mutually exclusive period parameters (monthly payer -> month, quarterly payer -> quarter 1-4 with quarterly period from company settings) and notes that a legal-person quarterly payer still files monthly KH, producing multiple submissions with khMonthly=true. It also covers an exclusion ("Identifikovana osoba kontrolni hlaseni nepodava") and the document-selection rule (approved only by default, DUZP else issue date, same as get_vat_summary).

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