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

The description discloses key behaviors beyond the annotations: payment is charged, codes are single-use and non-expiring, supported languages (en/ja), and the warning 'Treat codes like cash'. These are not in the annotations and add useful context. It does not contradict the provided annotation hints (readOnlyHint=false, idempotentHint=true).

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?

Two sentences pack a lot of information (price, quantity, unit cost, language, expiry, cash-like warning) without unnecessary words. The core purpose is front-loaded ('Volume pricing for style_report') and the warning is a natural close. It is slightly dense but each clause earns its place.

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 output schema, the description appropriately states what the tool returns (10 single-use credit codes). It covers pricing, language, expiry, and the code-handling warning. The payment-flow details (e.g., omitting x_payment to get requirements) are already in the schema, so the description is sufficiently complete for an agent to call 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%, and the x_payment parameter is already well-documented in the schema (base64 header, omission behavior). The description does not add parameter-level meaning beyond mentioning a '$19.90 payment' which aligns with the schema's payment concept. Since schema carries the full parameter semantics, baseline 3 applies.

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 resource (style_report) and the action (payment returns 10 single-use credit codes). It distinguishes report_pack from style_report itself by framing it as 'Volume pricing'. However, the verb is implicit ('returns' rather than an explicit 'purchase' or 'buy'), so it's slightly less direct than a fully specified action.

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 pricing comparison '$1.99/unit vs $2.99 single' implies usage when multiple style_report calls are needed, and the reference to style_report indicates a relationship to that sibling. But there is no explicit 'use this when' or 'use style_report for single calls' guidance, and no mention of when not to use it. The guidance is implied but not stated.

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