Financial ratios

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

The description discloses key behaviors beyond the annotations: determinism, the TTM summation rule for flow-based ratios on quarterly data, and the explicit 'null with a reason, never a guess' policy for missing inputs. These are valuable operational details not present in the schema or 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?

Two sentences with no fluff. The core purpose and ratio list are front-loaded, followed by the key behavioral nuance. Every sentence carries essential information.

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?

With an output schema present and annotations covering safety, the description addresses the most important behavioral nuance (missing inputs) and the TTM rule. It does not explain interaction between ticker and disclosure_id, but that is a minor omission given the schema descriptions.

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 description coverage is high (83%), so the baseline is 3. The description adds context about the ratios list and the TTM behavior that relates to period and frequency, but it does not explain each parameter beyond what the schema already provides. It adds marginal value without compensating for any gaps.

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 computes deterministic financial ratios and enumerates the specific ratio families (margins, liquidity, leverage, etc.). It distinguishes the tool from raw financial data tools like get_financials, though it does not explicitly name a sibling alternative.

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 usage context such as the trailing-12-month behavior for quarterly flow ratios and the null-with-reason behavior for missing inputs. However, it does not explicitly guide when to choose this tool over related tools like get_financials or get_metric_history, leaving that to the agent.

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