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

Annotations already establish read-only, non-destructive and open-world behavior, so the bar is lower. The description still adds genuine operational context: data provenance (straight from SEC filings), a metered cost of 6 credits, and the fact that several metrics are pre-computed rather than returned raw, which is real value 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?

It is a single front-loaded sentence that carries the resource, scope, source, derived metrics and cost with little waste. The opening 'Cash Flow Statement: Cash Flow Statement returns…' duplicates the title and name, a minor 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?

With an output schema present and full parameter documentation, the description only needs to cover scope, provenance and cost, all of which it does. An agent has enough to decide to call it and interpret the results 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?

Schema description coverage is 100%, so the year/quarter defaults and 404-on-missing-period behavior are already documented in the schema. The description only reinforces the ticker-based lookup and US-public-company restriction, adding little parameter-level meaning beyond that baseline.

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 names a specific result (operating, investing and financing cash flows) for a specific resource class (US public company by ticker) and adds the derived metrics it returns (free cash flow, FCF margin, cash conversion). That distinguishes it from adjacent finance siblings such as BalanceSheet, IncomeStatement and FinancialRatios without needing to name them.

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?

Usage is only implied: an agent can infer it should call this when it needs cash-flow data for a US-listed ticker, and the stated credit cost helps triage between tools. There is no explicit when-to-use versus alternatives guidance and no exclusions, such as the fact that non-US issuers are out of scope.

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