buy_email_pack

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

No annotations exist, but the description discloses that the tool returns a Stripe checkout URL (not a direct credit) and that credits activate under specific conditions. This adds behavioral context beyond what annotations would cover.

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, packed with essential details (price, quantity, activation conditions, return type) without any 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?

Given no output schema, the description adequately explains the return value (Stripe checkout URL) and activation logic. However, it does not mention potential error cases or prerequisites (e.g., having a custom sender domain already registered).

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 clear parameter descriptions. The description does not add new information beyond the schema, as it only restates 'email' and 'wallet' identifiers. Baseline 3 for high coverage.

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 states the tool purchases a $5 email pack of 10,000 non-expiring emails, specifying price, quantity, and activation conditions. It distinguishes from siblings like 'tier_checkout' or 'check_balance' by focusing on email pack purchase.

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 provides clear usage context: purchase when tier daily limit is exhausted and a custom sender domain is verified. It tells what the tool returns (Stripe URL) but does not explicitly mention when not to use it or alternatives.

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