Read the inbox of a long-term SMS rental: all received messages, newest first, plus the number's status and expiry. Read-only; poll it when the user expects a message. The receiptId comes from rent_sms_number or list_sms_orders. Requires a connected agent wallet.
| Name | Required | Description | Default |
|---|---|---|---|
| receiptId | Yes | The rental receipt ID from rent_sms_number or list_sms_orders |
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint, and the description reinforces it with 'Read-only' and adds behavioral details: polling suitability, requirement of a connected agent wallet, and return contents (messages, status, expiry). This goes beyond the annotation without contradiction.
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 focused sentences front-load the core purpose, then efficiently cover usage, prerequisites, and return content. No unnecessary words or repetition of schema fields.
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 single-parameter read-only tool with rich annotations, the description fully covers what the tool does, when to use it, prerequisites, and what it returns. No output schema exists, so describing the response content is sufficient.
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 covers 100% of the single parameter, and the description adds value by explaining where the receiptId originates (rent_sms_number or list_sms_orders), which is helpful context beyond the schema description.
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 reads the inbox of a long-term SMS rental, listing received messages newest first plus status and expiry. It distinguishes itself from siblings like cancel_sms_rental or list_sms_rentals by focusing on the inbox 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?
Provides clear when-to-use guidance: 'poll it when the user expects a message' and specifies the receiptId source. It lacks explicit exclusion of alternatives but gives sufficient context for correct selection among sibling rental tools.
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.