price_correlation

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

With no annotations, the description must carry the full burden of behavioral disclosure. It states the core computation ('compute price correlation matrix') and implies a return value (the matrix), but does not explicitly mention side effects, data source, or error handling. For a simple calculation tool, this is adequate but not rich in behavior detail.

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, with two clear sentences and a terse Args list. It front-loads the main purpose, then adds supporting detail without redundancy. Every sentence earns its place, and the structure is easy to parse.

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?

Despite being a simple tool, the description covers the core functionality, output type (correlation matrix), and parameter details. It does not mention edge cases or return format nuances, but given the absence of an output schema and the tool's simplicity, the description is sufficiently complete for an agent to use it correctly.

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 schema provides no descriptions for the two parameters, but the description compensates by specifying the format for symbols ('comma-separated ticker symbols'), the minimum count ('minimum 2'), and the allowed values for period ('1mo, 3mo, 6mo, 1y'). This goes beyond the schema's structural details and gives the agent the information needed to invoke the tool correctly.

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 opens with 'Compute price correlation matrix between multiple symbols,' which is a specific verb+resource pair that clearly distinguishes it from sibling tools like price_history or risk_assessment. The mention of 'multiple symbols' further clarifies its scope and differentiates it from single-symbol tools.

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 phrase 'Useful for portfolio diversification analysis' provides clear contextual guidance for when to use the tool. However, it does not explicitly state when not to use it or name alternative tools, though the context is sufficient to infer appropriate usage.

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