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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=false, so the safety profile of this pure-computation tool is fully covered. The description adds the return field (targetExitPrice) which is useful given there is no output schema, but it discloses nothing further about determinism, fee handling, or edge cases.

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?

Front-loaded with the core verb and resource, then two illustrative queries, then the return value. Every sentence earns its place and there is no filler.

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?

For a deterministic read-only calculator whose safety is covered by annotations and whose parameters are fully documented in the schema, the description is nearly complete and even covers the return field in the absence of an output schema. Detailed inverse/linear output handling is left to the schema, which is acceptable.

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 all 9 parameters, including the three enums (side, targetMode, contractType) and fee defaults, are already documented in the schema. The description only restates the PnL/ROE distinction without adding syntax or format detail beyond the schema.

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?

States a specific verb (Calculate) plus the exact resource (the exit price needed to hit a target PnL or ROE percentage), and disambiguates the two target modes. An agent can immediately distinguish this from sibling entry/sizing tools like run_average_down or run_position_sizing.

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?

Gives concrete trigger phrasing ('at what price do I take profit to make $500?', 'where should I set TP for 20% ROE?'), which clearly signals when to call it. However, it does not name alternatives (e.g., run_scale_out, run_pnl_planning, run_breakeven_planning) or state when NOT to use it.

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