The wallet ledger: every debit and credit (deposits, purchases, refunds) with amount, running balance, and description, newest first. Read-only and paginated; filter with type. Use this to reconcile spend or answer "where did the balance go" — check_balance only gives the current number.
| Name | Required | Description | Default |
|---|---|---|---|
| page | No | 1-based page (25 transactions per page) | |
| type | No | Only show this transaction type |
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true, and the description reinforces 'Read-only' while adding useful behavioral context: pagination, newest-first ordering, and filtering by type. It does not contradict annotations and adds value beyond them.
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 sentences, front-loaded with the core purpose and followed by usage guidance. No wasted words; every phrase adds value.
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?
Even without an output schema, the description explains what is returned (amount, running balance, description), the order (newest first), and pagination. For a read-only list tool with two optional params, this is fully 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?
Schema coverage is 100% for both parameters (page and type) with their own descriptions. The tool description mentions pagination and filtering but does not add meaning beyond the schema, 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 clearly identifies the tool as the wallet ledger listing all debits and credits with amount, running balance, and description, newest first. It distinguishes itself from siblings like check_balance by stating what it provides beyond a simple balance.
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 explicitly states when to use it ('reconcile spend or answer "where did the balance go"') and names a specific alternative (check_balance) with its limitation ('only gives the current number'). This gives clear guidance.
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.