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

Annotations already establish readOnly/idempotent/non-destructive/closed-world, so the bar is lower, and the description still adds real behavioral context: quotes are delayed ~15 minutes, values are in PLN, the TTM P/E falls back to the last annual filing, and the payload is a snapshot plus a few daily bars rather than full OHLCV history. It stops short of stating auth requirements, rate limits, or behavior when the company has no listing.

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?

It is a dense but well-structured pair of sentences that front-loads the resource and then the returned fields, which is justified given there is no output schema. The long field enumeration is functional rather than padding, though it could be tightened slightly.

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 no output schema, the description carries the burden of describing return values and does so thoroughly, including units (PLN), latency (15-minute delay), and scope limits (snapshot, not full history). The remaining gap is failure/edge-case behavior — no listing found, multiple name matches, or which identifier wins — which an agent would want for a zero-required-parameter 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 description coverage is 100%, so the three parameters (krs, nip, name) are already documented, and all are optional. The description restates the same identification guidance ('Keyed by NIP'; 'Identify company by name, KRS, or NIP') without adding format or precedence detail beyond the schema, so the baseline 3 applies.

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 gives a specific verb+resource ('Get Warsaw Stock Exchange listing for a company') and then enumerates exactly what is returned (ticker, ISIN, market, close/change, market cap, EPS, P/E, dividends), which cleanly separates it from the sibling registry tools like get_company or get_company_people. An agent can tell this is the market-data tool without opening any schema.

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 gives the lookup key guidance ('Keyed by NIP', 'Identify company by name, KRS, or NIP'), which is useful selection context. However, it never contrasts itself with the obvious sibling get_company (company registry data), nor states when-not to use it (e.g. for historical OHLCV, which it only hints at). Usage is therefore implied rather than directed.

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