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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safe read-only nature is covered. The description adds useful behavioral detail about what market data fields are returned (volume, market cap, P/E ratio, etc.) but does not discuss data latency, market hours, symbol validity, or error behavior. It does not contradict the annotations.

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 two sentences, front-loaded with the core action, and includes both return fields and representative user queries. It is reasonably concise, though the long field list could be slightly trimmed without losing critical information.

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, read-only tool with no output schema, the description is largely complete: it states what the tool does, what data it returns, and when to use it. It does not cover edge cases such as invalid symbols, market closure behavior, or data delay, but those are not critical for selecting and invoking a basic stock quote 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 coverage is 100%: the only parameter, symbol, is already described with examples in the input schema. The description does not add additional semantic meaning beyond restating that this handles stock price questions, so the baseline score of 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 clearly states the tool gets the latest available stock price and market data for a single symbol, which is a specific verb+resource. It differentiates from siblings like stock_history and stock_quote_batch by emphasizing 'latest available' and singular stock/equity price questions, though it does not explicitly name those alternatives.

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 gives concrete example queries ('what's the stock price of X?', 'how is AAPL doing?') and says to use it for any stock/equity price question. This provides clear context for when the tool is appropriate, but it does not mention exclusions or direct users to alternatives for history, comparison, or batch quotes.

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