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

No annotations are provided, so the description carries the full burden of behavioral disclosure. However, it only restates the purpose and does not disclose whether this is a read-only operation, the output format, or any constraints like the need for both from and to dates. This lack of behavioral detail is a significant gap.

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, consisting of two sentences that are front-loaded with the main action and followed by the use case. Every word contributes value, 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 straightforward calculation tool with a well-documented schema, the description is adequate but not comprehensive. It lacks sibling differentiation and does not mention any prerequisites, output shape, or edge cases, leaving the agent to infer details from the schema alone.

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 descriptions for all five parameters (100% coverage), so the description does not need to explain them. The description adds no extra meaning beyond what the schema already states, aligning with the baseline of 3.

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's function: 'Calculate the Standard Deviation for a stock using the FMP Standard Deviation API.' It uses a specific verb (calculate) and resource (standard deviation for a stock), and the second sentence explains its purpose in volatility/risk analysis, distinguishing it from other technical indicator tools like getSMA or getRSI.

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 provides clear context for when to use the tool: 'This tool helps users analyze volatility and risk associated with historical price data.' It implies usage for risk assessment but does not explicitly mention alternatives or when not to use it, which keeps it slightly below a 5.

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