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

Annotations already declare readOnlyHint=true, so the safety profile is covered, and the description adds the GET /contact/ endpoint and pagination via rows_limit/rows_offset. It does not describe return ordering, total counts, or empty-result behavior, so it is adequate but not rich beyond the structured fields.

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?

Tight and front-loaded: the search verb and resource lead, followed by return fields, filters, pagination, and endpoint, with no filler sentences. The dense field listing is efficient rather than padded.

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?

For a read-only list tool with 100% schema coverage, no required params, and no output schema, the description covers filters, pagination, returned fields, and the HTTP endpoint. Nothing critical is missing, though it could clarify the 'tel' vs 'phone' naming and result semantics.

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 description coverage is 100%, so every parameter is already documented in the schema, making 3 the baseline. The description merely restates the filters (though it says 'phone' where the schema param is 'tel') and adds no syntax or format detail beyond the schema.

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 ('Search the address book'), and enumerates the returned fields (id, name, company, ICO, DIC, address, e-mail, phone, days_due), so the agent knows exactly what it retrieves. It does not explicitly name a sibling to distinguish itself from, but list-vs-get is inherent in the name.

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 says which attributes can be filtered (q, ICO, DIC, name, e-mail, phone), which implies usage context, but it never states when to use this versus vyfakturuj_get_contact or other list tools, nor any exclusions. Usage is implied rather than explicit.

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