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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint, covering the safety profile. The description adds the 'live/delayed' qualifier and lists returned fields, but does not elaborate on delays or other behavioral nuances. It adds modest value beyond annotations without contradiction.

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 sentence that front-loads the purpose and immediately gives a concrete example. Every word earns its place, and the structure is highly efficient for an agent scanning tool definitions.

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?

With no output schema, the description must convey what data will be returned, and it does list the key components (bid/ask/mid/last, change, volume). It omits potential details like currency or timestamp, but for a simple quote tool this is adequate. The optional fiftyTwoWeek parameter is only in the schema, not the description, which is acceptable given schema coverage.

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 provides 100% parameter descriptions, so the baseline is 3. The description contributes an example call but no additional semantics beyond what the schema already explains. It does not clarify the _apiKey format or fiftyTwoWeek effect beyond the schema.

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 a stock quote with specific data points (bid/ask/mid/last, change, volume) and includes a concrete example. This distinguishes it from sibling tools like marketdata_candles or marketdata_option_quote, which target different instruments or data shapes.

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 implies usage for stock quotes but does not explicitly contrast with alternatives or state when not to use it. An agent could infer that options-related tools are for options, but no direct guidance is given, leaving room for ambiguity.

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