search_nip

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

The annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint, but the description adds valuable behavioral context beyond those hints: it discloses the daily rate limit for the `search` method, lists specific error codes (invalid_nip, invalid_date, not_found, rate_limit_daily, upstream_error), and explicitly describes the return fields. This is a strong disclosure of operational 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?

The description is a compact four-sentence paragraph, front-loaded with the primary purpose. It then efficiently covers return data, rate limits, and error codes without redundant explanations. Every sentence earns its place, and the structure is clean.

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, so the description correctly compensates by listing the returned fields (VAT status, name, REGON, KRS, address, registration/deregistration dates, bank accounts). It also addresses rate limits and possible errors. For a simple tool with two parameters, this is complete and actionable.

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 covers both parameters thoroughly: `nip` has format details (10 digits, optional hyphens) and `date` has format (YYYY-MM-DD) and default value (today). The description adds little parameter-specific meaning; it only reinforces that lookup is by NIP. With 100% schema coverage, 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 uses a specific verb 'Sprawdza' and clearly identifies the resource: 'podmiot w Wykazie Podatnikow VAT (biala lista) po numerze NIP'. It distinguishes itself from sibling tools like search_regon and search_bank_account by specifying NIP as the lookup key and enumerating the returned data (VAT status, name, REGON, KRS, address, dates, bank accounts).

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 clearly indicates when to use the tool: to verify a taxpayer in the VAT registry by NIP. It also provides practical usage context such as the daily limit (100/day per IP) and error codes. However, it does not explicitly mention alternative tools for REGON or bank account lookups, so it stops short of full when-not-to-use guidance.

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