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

Goes well beyond readOnly/idempotent annotations: warns that coverage varies, that missing data is not zero, that monetary fields are in millions of the issuer's reporting currency (EUR or USD, not necessarily PLN despite the field suffix), and that fields lacking complete provenance are absent. The dataQuality.blocksComputation and withheld semantics explain why a null appears — exactly the non-obvious behavior an agent would otherwise misread.

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?

Front-loads purpose in the first clause, then moves to resolution rules and then to return-value caveats in a logical order; every sentence carries information. It is dense and backtick-heavy, sitting near the upper limit of comfortable length, but nothing is redundant.

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 must explain the response shape and it does: values.<field> internals, currency/unit/report date/source URL provenance, reportScope standalone vs consolidated, and the null-vs-withheld distinction. An agent can interpret the payload correctly without guessing.

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 both parameters are already documented, giving a baseline of 3. The description adds only that instruments resolve by ticker, alias or ISIN, which extends the schema's narrow 'KGH.PL canonicalized' note but does not clarify quartersBack behavior.

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+resource and enumerates the KPI families (revenue, EBITDA, EBIT, net income, EPS, balance sheet, cash flow) plus reported vs adjusted. It is distinguishable in substance from get_financial_ratios and get_public_price_history, but it never names those siblings, so route selection rests on the agent's own inference.

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?

Usage is only implied: the quarterly-KPI framing suggests annual/ratio/dividend queries belong elsewhere, but no explicit when-to-use or when-not statement and no named alternative appear. The agent must infer the boundary from the sibling names alone.

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