Purchases a compatible top-up package using the wallet balance. Requires a valid session token.
| Name | Required | Description | Default |
|---|---|---|---|
| token | No | The secure session token returned by verify_agent_otp. | |
| orderId | Yes | The ID of the active eSIM order. | |
| packageCode | Yes | The top-up package code to purchase. |
Changes observed during successful MCP inspections.
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description must disclose behavior. It indicates that the purchase uses wallet balance (implied deduction) and requires a token, but omits details on success/failure handling, reversibility, or idempotency.
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 concise sentences, no wasted words, and front-loaded with the core action.
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?
The description covers the main action and requirement, but could be more complete by mentioning that the package must be from get_topup_packages or that the order must be active.
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%, and the description reinforces the token's origin (verify_agent_otp) but does not add significant meaning beyond what the schema already provides.
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 uses a specific verb ('Purchases') and resource ('compatible top-up package') and clearly distinguishes from siblings like purchase_esim_with_wallet and get_topup_packages.
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 mentions the session token requirement from verify_agent_otp, but does not explicitly state when not to use this tool or compare with alternatives like other purchase methods.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
