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

With no annotations provided, the description carries full behavioral burden. It only states the return format and cashflow structure, omitting details about error handling, convergence behavior, or assumptions (e.g., periodic cash flows). For a financial tool, this is insufficient.

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 sentences that front-load the purpose. It avoids unnecessary words, though it could be improved by separating parameter details more clearly.

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?

Given the complexity of IRR calculation and absence of output schema/annotations, the description is incomplete. It does not address edge cases like multiple IRRs, non-convergence, or cashflow periodicity, leaving important gaps for an AI agent.

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 0%, so the description must compensate. It explains the cashflows array format and makes the guess parameter implicit (only default shown in schema). The description adds meaningful context for cashflows but neglects to explain the guess parameter's role.

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 calculates Internal Rate of Return (IRR) for cashflows, with a specific verb and resource. It distinguishes from sibling tools like calculate_npv and calculate_statistics by focusing on IRR.

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 the required format for cashflows (initial investment negative, then cash flows) and mentions the return value, giving context on when to use. However, it does not offer explicit guidance on when not to use or discuss alternatives like calculate_npv.

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