List available top-up packages for an existing eSIM, including price and data amount. Use this before topup_esim to find valid package codes. Requires an agent-wallet API key (ak_live_).
| Name | Required | Description | Default |
|---|---|---|---|
| iccid | Yes | ICCID of the eSIM to get top-up options for |
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true, and the description adds meaningful context beyond that: it requires an agent-wallet API key (ak_live_), applies to existing eSIMs, and indicates output contains package codes with price/data. This is richer than merely restating the annotation, though it doesn't cover failure modes or response format.
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?
Three concise sentences each serve a distinct purpose: what the tool does, when to use it, and a credential requirement. No redundant wording, and the key information is front-loaded.
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 simple one-parameter read-only tool with no output schema, the description covers purpose, usage sequence, output content, and API key requirement. It lacks explicit error/edge-case handling, but that is not essential for this level of complexity, making it nearly complete.
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?
The single parameter iccid is fully described in the schema with 'ICCID of the eSIM to get top-up options for'. The description adds marginal context by saying 'existing eSIM' and 'valid package codes', but the schema already carries the semantic weight, so baseline 3 is appropriate.
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 ('List') and resource ('available top-up packages for an existing eSIM'), and specifies the output includes price and data amount. It also distinguishes this from the sibling topup_esim by showing how it fits into the workflow.
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?
Explicitly states 'Use this before topup_esim to find valid package codes', naming the exact alternative and giving a clear sequence. Also mentions the required API key type, which helps the agent decide when this tool is appropriate.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Add one secure layer between your agents and this server.
There is notable overlap between search tools (search, search_esim_packages, search_phone_plans) and detail tools (fetch, get_package_details, get_pricing, get_phone_plan_pricing). While descriptions clarify some differences, agents may struggle to pick the right tool without careful reading, especially between 'search' and 'search_esim_packages' and between 'fetch' and 'get_package_details'.
Most tools follow a clear verb_noun convention (e.g., purchase_esim, list_orders, get_balance). A few are single verbs like 'fetch' and 'search', which stand out but are still recognizable as actions. Overall the pattern is predictable and readable.
With 31 tools, this is a large set. The server covers several distinct sub-domains (eSIM data, phone-number eSIM, SMS verification, SMS rentals, wallet management), which justifies some size, but the count is on the high side and could be consolidated (e.g., merging search tools or detail-fetching tools).
The tool surface covers the full lifecycle for each product line: search, view details, purchase, list, check status, top-up/cancel, plus wallet management. The only minor gap is a lack of explicit update tools (e.g., changing a phone plan), but core workflows are well supported.