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

The description adds substantial behavior beyond the readOnlyHint and openWorldHint annotations: it explains that PDF-only filings (including all IFRS groups) are not in the dataset and that an empty answer is not evidence of absence, and it discloses the payment mechanism and cost (x402, $0.01). This directly informs the agent how to interpret results and plan payment. No contradiction with annotations.

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?

Each sentence contributes: the opening states the core function, the middle enumerates returned data and coverage caveats, and the closing covers payment. Despite its length, nothing is filler; the critical caveats (empty result ≠ no accounts, sole traders excluded) are front-loaded before payment details.

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 an output schema present and annotations covering read-only and open-world behavior, the description covers the remaining agent-relevant context: what fields to expect, how to interpret absence of data, which entities are excluded for GDPR, and how to pay. No significant missing information stands out for a list-style tool.

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 value by stating the exact cost ('$0.01 in USDC or EURC') and how the x402/api_key payment paths relate, which is not fully spelled out in the schema descriptions. The main parameter (ico) is already well documented by the schema's pattern and example, so the description need not repeat it.

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-resource pair: 'list the fiscal years of a Slovak company' and enumerates the exact fields returned (closing date, period, filing type, form model, scope, link), distinguishing it from the sibling get_slovak_company_filing by its listing scope. It also explicitly carves out what it does not cover (PDF-only IFRS filings, sole traders), leaving no ambiguity about the tool's function.

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 gives clear context: use it when you need the structured annual-account history for a Slovak IČO, and it warns when it will not help (PDF-only IFRS groups and sole traders are absent). However, it never explicitly names the alternative tool (e.g., get_slovak_company_filing) or states a when-not-to-use selection rule, so it stops short of the 'explicit alternatives' bar.

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