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

With no annotations provided, the description carries the full burden of behavioral disclosure. It does disclose what is returned (single numeric value) and what is omitted (high/low, percentage change, etc.), and it notes the limitation of not supporting crypto. However, it lacks details on data freshness/delay, error behavior for invalid tickers, or rate limits, which are relevant for a price lookup tool. This is adequate but not rich.

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 efficient and front-loaded, with the core purpose in the first sentence. It uses a few sentences to convey purpose, scope, alternatives, and exclusions, and every sentence adds value. It is slightly longer than strictly necessary but remains clear and not verbose.

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 fairly complete: it explains the return type, what is omitted, when to use this versus stock_quote, and what not to use it for (crypto). Minor gaps remain about data sources, update frequency, and error handling, but these are not critical for a lightweight price lookup. The description competently covers the main contextual needs.

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 already provides 100% coverage for the single parameter 'symbol', with a detailed description and examples. The tool description adds little beyond restating 'by ticker symbol,' so it does not meaningfully augment the schema. The baseline of 3 is appropriate since the schema does the heavy lifting.

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 immediately identifies the tool as retrieving the current trading price for a publicly listed stock by ticker, and specifies the output as a single numeric value. It also explicitly distinguishes itself from the sibling stock_quote by stating 'lightweight variant' and listing omitted fields, making the purpose and scope unmistakable.

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 provides clear when-to-use guidance: 'Use stock_price_lite when only the raw current price is needed for a quick lookup or calculation. Prefer stock_quote when the agent also needs price change, intraday range, company information, or a fully structured response.' It also explicitly excludes cryptocurrency and directs users to crypto_price or crypto_price_lite, offering clear alternatives.

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