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

Annotations already declare this a safe, idempotent, closed-world read, so the description is not burdened with safety disclosure. It adds genuine behavioral context beyond the annotations: the result is deterministically computed by the same function as a known calculator page ('not estimated'), and it discloses the shape of the return (inputs, each result with its unit, formula, and page link).

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?

Three sentences, front-loaded with the computed outputs, followed by provenance and return format. Minor redundancy: the page link is referenced twice ('linked in the result' and 'the page link'), and the educational disclaimer is boilerplate, but overall it is tight.

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?

There is no output schema, and the description compensates by stating what is returned (inputs, each result with its unit, the formula, the page link). With 100% parameter coverage and a closed-world read annotation, an agent has enough to call and interpret the tool 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 schema already documents entry, stop, target, exit, and lang with units and constraints. The description only echoes that exit is optional and an R multiple, adding little beyond the schema. Baseline 3 is appropriate when the 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 names a specific verb and a concrete set of outputs (risk/reward ratio, breakeven win rate, optional R multiple), which is far more specific than a tautology. It is clearly a calculator, and the outputs differentiate it in substance from siblings like calculate_kelly_criterion or calculate_position_size, though it never names an alternative explicitly.

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 implied by 'of a planned trade,' which signals a pre-trade evaluation context, but there is no explicit when-to-use, when-not-to-use, or routing to a sibling calculator. An agent can infer the scenario but must guess about overlap with calculate_expectancy or calculate_position_size.

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