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

Annotations already mark the tool as read-only, idempotent, and non-destructive. The description adds valuable behavioral context: data is delayed rather than real-time, the source is Yahoo Finance, and there is a per-call cost of $0.005—information not available from annotations or schema.

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 a single compact line that front-loads the core purpose and then adds source, cost, and endpoint details. Every element contributes meaningful information with no redundancy or filler.

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 one-parameter read-only tool with no output schema, the description provides enough to invoke it correctly: asset class, data delay, source, and cost. It could name the specific quote fields, but that is not necessary for selecting or calling the 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 description coverage is 100%, so the schema already documents the single 'symbol' parameter with an example. The description does not add parameter-level detail, so the baseline score of 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 clearly states the tool returns a delayed quote and key stats for equities, ETFs, and indices, naming Yahoo Finance as the source. This scope distinguishes it from sibling tools like v1_crypto_price and v1_fx, which cover different asset classes.

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 asset-class scope ('equity/ETF/index') tells the agent when this tool is appropriate, and by contrast implies crypto and FX are handled elsewhere. It does not explicitly name alternatives or give exclusion conditions, but the context is clear enough for correct selection among the listed siblings.

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