stock-quote

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

Annotations already declare readOnly and non-destructive behavior. The description adds useful behavioral context beyond annotations: per-call cost, wallet requirement, Yahoo Finance backing, keyless access, practical absence of rate limits, and 'clean JSON' output. No contradiction with 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 dense but well organized: cost/wallet requirement first, then core behavior and fields, then alternative routing, then data source, then symbol formats. Every sentence contributes useful information without redundancy.

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 output schema exists and the description covers returned fields, data source, authentication/cost, supported symbol classes, and exclusions, there is no significant missing context for an agent to call this tool 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?

Schema description coverage is 100%, so the schema already documents both symbol and Idempotency-Key. The description's symbol examples reinforce the schema but do not add meaning beyond it; baseline 3 is appropriate.

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 names a specific verb and resource: 'Live stock/index/FX/crypto quote' with a precise list of returned fields. It also distinguishes this tool as a 'single-symbol NOW read,' which clearly separates it from historical or pre/post-market tools.

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 explicitly states when to use alternatives: 'for OHLC time series use stock-history, for pre/post-market use premarket-quote, and for crypto pairs crypto-price returns richer market fields.' This gives an agent direct routing guidance.

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