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

Annotations already declare readOnlyHint=true, so the safety profile is covered. The description's value-add is the return-field breakdown, which is genuinely useful behavioral context given there is no output schema. However, it discloses nothing about rate limits, data freshness/delay, or the REST endpoint's auth needs, keeping it at a minimum-viable level.

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?

Two tight sentences; the purpose is front-loaded and the field list is compact and informative. No filler or redundant restatement of the name.

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 tool with no output schema, the description compensates well by enumerating the returned fields. Minor gaps remain, such as currency/units and whether the quote is delayed, but nothing essential to invoking it is missing.

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%, and the single symbol parameter is fully documented in the schema with an example ('AAPL'). The description adds no parameter syntax or format detail beyond what the schema already provides, so the baseline 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?

States a specific resource ('real-time quote for a stock') and enumerates the exact return fields, so an agent knows precisely what this returns. It is clearly distinct from siblings like basic_financials or company_profile, though it does not explicitly name the differentiation.

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?

There is no when-to-use guidance or mention of alternatives. With fifteen sibling tools, nothing tells the agent to reach for finnhub_quote versus basic_financials or price_target for valuation-style data. Usage is only implied by the name.

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