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

Annotations already declare readOnlyHint=true and openWorldHint=true. The description adds valuable context by specifying 'real-time price' and listing the return fields, which clarifies the dynamic, up-to-date nature of the data. It does not disclose potential latency or error behavior, but for a simple read-only tool, the provided context is sufficient.

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 concise and well-structured: it states the core action in the first sentence, enumerates the returned data in the second, and provides use cases in the third. Each sentence adds distinct value with no waste or 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?

For a simple single-parameter tool with no output schema, the description covers the purpose, return fields, and use cases thoroughly. It does not discuss error handling or latency, but these are not critical for a straightforward read-only quote tool, making the description reasonably complete.

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 fully documents the 'ticker' parameter with a description and examples (100% coverage). The description does not add further parameter-specific information beyond restating that it is for an individual ticker symbol, so the schema carries the burden adequately.

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 uses a specific verb ('Fetch') and resource ('stock market quote') with a clear scope ('individual ticker symbol'), which distinguishes it from sibling tools like get_multiple_quotes and compare_stocks. It also enumerates the specific data points returned, leaving no ambiguity about the tool's 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?

The description clearly states intended use cases ('real-time price monitoring, investment decisions, or financial dashboards'), providing context for when to use the tool. However, it does not explicitly mention alternatives or exclusion criteria for the sibling tools, though the 'individual ticker symbol' phrasing implies single-query use.

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