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

With annotations already indicating read-only and idempotent behavior, the description adds value by explaining the return behavior (periods used, null when no defensible bridge) and the exact calculation logic. This goes beyond the 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 a single, well-structured sentence. It front-loads the purpose, includes the calculation method, and notes the null condition, with no wasted words.

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?

The tool has only one parameter and no output schema. The description covers the calculation methodology, the return value (periods used), and the null condition, making it complete for an agent to understand expected behavior.

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% for the single 'company' parameter (Ticker, company name, or CIK). The description does not add additional parameter semantics beyond what the schema already provides, so baseline 3 is appropriate.

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 specifies a clear verb ('Calculate') and resource ('trailing-twelve-month SEC-tagged R&D expense and operating cash flow'), and outlines the methodology. It distinguishes itself from sibling tools like get_company_financials by focusing on a specific derived metric.

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 implies the tool is for computing TTM R&D burn from SEC filings, which is clear context. It does not explicitly list alternatives or exclusions, but the context is evident given sibling tools like get_liquidity_runway. A 4 is appropriate for clear context without exclusions.

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