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

Since no annotations are present, the description carries the burden and does well by stating it returns a single numeric value, omits certain metadata, and does not support crypto. It could mention error behavior or data delays, but for a simple lookup, this is sufficient disclosure.

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 well-structured with three sentences: the core function, the comparison to stock_quote, and the crypto exclusion. Every sentence provides value without redundant fluff, making it concise and front-loaded.

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?

Given the tool's simple nature (one required parameter, no output schema), the description is complete: it defines the return type, clarifies scope, and points to alternatives. No critical information is missing for an agent to select and invoke it correctly.

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 fully documents the symbol parameter with examples and validation (100% coverage), so the description adds little beyond restating 'ticker symbol'. Baseline 3 is appropriate since the schema does the heavy lifting and the description does not conflict or add meaningful new detail.

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 clearly states the tool retrieves the current trading price for a stock by ticker, and explicitly differentiates itself from stock_quote as a lightweight variant. It specifies the return value as a single numeric price, leaving no ambiguity about its function.

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?

Provides explicit usage guidance: use when only raw price is needed, prefer stock_quote for additional fields, and use crypto_price/crypto_price_lite for cryptocurrencies. This directly addresses when and when not to use the tool versus alternatives.

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