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

Annotations already indicate readOnlyHint=true, openWorldHint=true, idempotentHint=true, and destructiveHint=false, covering safety. The description adds performance context ('cheapest and fastest way') and clarifies it returns real-time snapshot data. It does not mention pagination or limits, but for a simple single-stock snapshot this is acceptable. 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 efficiently structured: it front-loads the return fields, then states the required parameter, gives usage guidance, and names alternatives. No filler or redundant phrases. Every clause contributes to the agent's decision or call correctness.

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 an output schema present, the description doesn't need to explain return values, yet it still lists the fields. It covers the sole parameter, provides usage context, and differentiates from related tools. For a simple read-only snapshot tool, everything an agent needs to invoke it correctly is present.

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%: the only parameter `ticker` is fully documented in the schema ('The stock ticker symbol (e.g. AAPL, MSFT).'). The description repeats that `ticker` is required, which adds no new meaning beyond the schema. A baseline score of 3 is appropriate given exhaustive schema docs.

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 the current price of one stock with specific fields (`price`, `day_change`, `day_change_percent`, `time`). It explicitly distinguishes itself from sibling tools: `get_financial_prices` for historical series and `get_financial_financial_metrics_snapshot` for valuation multiples. The verb 'get' and resource 'financial prices snapshot' are specific, making the purpose unambiguous.

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 gives explicit when-to-use guidance: 'Use it whenever the question is "what is it trading at now"'. It also provides direct alternatives for different use cases, naming `get_financial_prices` for date range bars and `get_financial_financial_metrics_snapshot` for valuation multiples. This clearly tells the agent when to choose this tool and when not to.

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