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

The description adds rich behavioral context beyond the readOnlyHint and openWorldHint annotations: it discloses the 100-item cap, the return set (reliability status, accounts, tax office), the absence of name/address, the one-entry-per-DIČ behavior, and the meaning of NENALEZEN. This gives the agent a clear picture of the tool's edge cases and output semantics.

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 description is tightly structured in three sentences. The first sentence states the core function and limit, the second adds the key differentiator and use case, and the third clarifies output mapping and special sentinel. Every sentence provides value with 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?

Given there is no output schema, the description adequately explains the return value shape (reliability status, accounts, tax office), the one-entry-per-input behavior, and the interpretation of NENALEZEN. It also covers the API limit and use case, making it complete for a screening tool despite the missing output schema.

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?

The input schema already has 100% description coverage for both parameters (dics and icos), including the IČO-to-DIČ conversion. The description adds some behavioral context ('up to 100', 'one entry per input DIČ') but does not meaningfully expand on parameter semantics beyond what the schema already states, so the baseline of 3 is appropriate.

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 ('Bulk reliability check') and clearly identifies the resource (up to 100 Czech subjects) and scope (one ADIS request). It also explicitly contrasts with the single-subject sibling tool and describes the returned fields, distinguishing it from check_dph_payer and list_unreliable_payers.

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 provides clear context: it is 'lighter than the single-subject check' and 'useful for screening invoice-issuer lists or supplier portfolios.' It does not explicitly state when not to use it or name alternatives directly, but the comparison to the single-subject check implies when a more detailed lookup might be needed.

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