fba_profit

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

With no annotations, the description carries full burden. It discloses the inclusion of 2026 hidden fees, parameter defaults (including conservative organic traffic), and the full set of return metrics. For a calculator, this is transparent; it doesn't discuss side effects or external calls, which are not applicable.

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 well-structured: a headline purpose, a list of args that is necessary given no schema descriptions, a returns line, and a clear usage directive. Every sentence earns its place; no 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?

Given 12 parameters, no output schema, and no annotations, the description provides a complete picture: it defines all inputs, output metrics, and when to use the tool. No critical information is missing for an agent to invoke it 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 has 0% description coverage, but the description compensates excellently by listing every parameter with units, examples, and defaults (e.g., 'purchase_cost_cny: 1688/supplier unit cost in CNY (e.g. 27)'). This adds significant meaning beyond the schema's bare property names.

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 clearly identifies the tool as an FBA profit calculator for Amazon unit economics, with a specific verb ('calculates') and resource ('FBA products'). It lists outputs (breakeven price, profit, ACOS, etc.), distinguishing it from sibling tools like keyword_analyze or asin_score.

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 'USE THIS TOOL WHEN: Evaluating profit viability of a product before sourcing' provides explicit use context, but does not mention when-not-to-use or name alternatives. Since the tool's function is unique among siblings, this is sufficient but not fully exhaustive.

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