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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It reveals nothing: not that this is a read-only computation, not whether it requires numeric inputs, not what it returns, and not that the two inputs are netted together. For a tool with zero structured safety signals this is a critical gap.

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 single sentence repeats the same phrase twice with a colon, which is redundancy rather than conciseness. Brevity here reflects under-specification, not efficiency; there is no front-loaded purpose or useful structure to speak of.

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 no annotations, no output schema, and a two-parameter computation, the description should minimally state the formula, the expected input format, and the return shape. It supplies none of these, leaving the agent with essentially the tool name alone to work from.

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?

Both parameters have schema descriptions, but they are themselves tautological ('OperatingCashFlow to process'), so the nominal 100% coverage conveys no real meaning. The description adds nothing: it never states that FCF is derived by subtracting capitalExpenditure from operatingCashFlow, nor what units or format the string inputs expect.

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 is a pure tautology: it restates the tool name 'x402-free-cash-flow' as 'Free Cash Flow: Free Cash Flow' and adds no verb. An agent cannot tell from the text whether this computes FCF (= operating cash flow − capital expenditure), looks it up, or formats it. The resource is identifiable but the action is not.

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?

There is no when-to-use guidance, no prerequisites, and no mention of alternatives. The sibling list contains many finance tools (x402-price-to-cash-flow, x402-cash-conversion-cycle, x402-operating-cycle), and nothing here distinguishes this tool from them or states the conditions under which FCF is the right call.

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