get_fundamentals

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

With no annotations, the description carries the full burden of behavioral disclosure. It does disclose an important trait: 'Fields may be null if not available for a given symbol/exchange'. However, it does not describe output structure, error behavior, data freshness, or symbol validation, so the behavioral picture remains partial.

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 concise and front-loaded: it opens with the core purpose, follows with the null-field caveat, and ends with a clear Args section. No sentence is wasted, and the structure is easy to scan.

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 simple one-parameter tool with no output schema, the description is largely complete: it states the tool's purpose, lists representative fields, documents the only parameter, and flags nullability. It could be strengthened by briefly describing the expected return shape or behavior for invalid symbols, but these are minor gaps given the tool's low complexity.

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 schema provides only the property name 'symbol', but the description adds meaningful semantics: 'Stock ticker symbol, e.g. "AAPL" or "MSFT"'. This fully compensates for the 0% schema description coverage and gives the agent concrete examples for the single required parameter.

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 states a specific verb and resource: 'Get valuation/financial ratios for a stock symbol', and lists concrete fields such as P/E, market cap, EPS, and dividend yield. This clearly distinguishes it from sibling tools like get_quote, get_candles, and get_technical_indicators, which are about prices and technical analysis rather than fundamentals.

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 implies when to use the tool (when you need valuation or financial ratios) but provides no explicit guidance on alternatives or exclusions. It does not mention that get_quote should be used for current price or get_candles for historical prices, leaving the routing to inference.

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