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

With no annotations, the description carries the behavioral burden. It discloses key traits: the agent never holds a key, results appear on the page, the link is free, top-up links can be paid by anyone, and eSIM links deliver to the payer. It does not mention the API return value or error behavior, but the provided traits go beyond the schema.

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 relatively long but every sentence adds value: purpose, use case, security trait, delivery semantics, cost, and referral benefit. It front-loads the core purpose and usage condition, though some marketing phrasing like 'send it to family' could be trimmed.

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 tool with 8 parameters, no annotations, and no output schema, the description should clearly state what the tool returns to the caller. It describes the payer's experience (result appears on the page) but does not explicitly say the tool returns a checkout URL or link. This gap leaves the agent uncertain about the direct response, making it incomplete.

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 75%, so the description adds meaningful context beyond the schema. It explains `ref` as an Algorand address for referral earnings, and maps `type` values (topup/esim) to payment and delivery behavior. However, `offerId` remains unexplained, so it doesn't fully compensate for the undocumented parameter.

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 creates a checkout link where a human pays from their own Algorand wallet, which is a specific verb, resource, and payment model. It distinguishes from likely sibling 'buy' by emphasizing 'no wallet' and self-payment, though it does not name the sibling explicitly.

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?

It gives explicit when-to-use guidance: 'Use this when you have no wallet, or when the person should approve and pay themselves.' It also clarifies delivery semantics for top-up vs. eSIM links, but does not state when not to use or explicitly name alternatives, so it falls short of a 5.

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