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

Annotations already declare readOnlyHint=true and title, so the description adds value by stating 'Deterministic mathematical execution with zero language model confabulation,' which reassures the agent of no hallucination risk. This goes beyond the bare annotations, but could further detail edge cases (e.g., handling of missing periods or negative values).

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 two concise sentences, front-loaded with the core purpose and followed by a key behavioral guarantee. Every sentence earns its place without redundancy.

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 output schema exists and parameters are fully described in the schema, the description covers the essential context for a deterministic computation tool. It lacks mention of error handling or period validation, but for a well-typed tool with an output schema, this is nearly complete.

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?

With 100% schema description coverage, the description does not need to elaborate on parameters. However, it provides no parameter-specific details beyond the schema, such as clarifying that 'company' expects ticker or name consistently, or that 'low_tokens' only affects output, not behavior. Baseline 3 is appropriate as schema does the heavy lifting.

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 uses specific language: 'Exact compound annual growth rate (CAGR) calculation over verified SEC filing facts,' clearly indicating a resource (SEC filings) and verb (compute). It distinguishes itself from siblings by mentioning deterministic execution and zero confabulation, which contrasts with potential LLM-based tools like query_financial_sec.

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 usage for accurate CAGR calculations but does not explicitly state when to use it over siblings like lattice_arith_evaluate or query_sec_metric_exact. Alternatives are not named, and no when-not-to-use guidance is provided, leaving the agent to infer context.

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