Calculate Position Size

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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint false, so the agent knows it's a safe read-only calculation. The description adds the specific calculation logic (shares such that stop loss costs no more than risk_percent) and the extra ATR-based stop distance output, going beyond the annotation information.

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 sentences, front-loaded with the core purpose, and the second sentence adds one useful extra output detail. No wasted words.

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 5 parameters, 100% schema coverage, and no output schema, the description fully explains what the tool computes and what it returns (shares and ATR stop distance). The read-only annotations cover side effects, so no further behavioral context is needed.

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 coverage is 100%, with all five parameters described in the schema. The description does not add significant parameter-level meaning beyond what the schema already provides; it's consistent with the schema's definitions of risk_percent and stop_loss_price.

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 a specific verb ('sizes a position') and explains the risk-based method, clearly distinguishing it from order-entry tools like draft_order. It also mentions the ATR stop distance, further clarifying its calculation role.

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 when a risk-based position size is needed ('rather than gut feel'), but it does not explicitly name alternatives or state when not to use. Among siblings like draft_order and get_portfolio_risk, the description gives enough context to infer its purpose, but lacks explicit exclusions.

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