Check what PikaSim plans cover a country. Returns TWO buckets: DATA eSIMs (count, price range, data amounts) and PHONE-NUMBER eSIMs (count, price range — a real carrier number with voice + SMS).
| Name | Required | Description | Default |
|---|---|---|---|
| country | Yes | ISO 3166-1 alpha-2 country code (e.g., JP, US, DE) |
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint and openWorldHint, so the safety profile is covered. The description adds behavioral context by disclosing the two-bucket response structure, including what counts as a PHONE-NUMBER eSIM (real carrier number, voice + SMS), which is a meaningful distinction beyond the schema. It does not contradict annotations.
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 exactly two sentences: the first states the primary action, the second details the return structure. Every phrase earns its place, and the use of capitalized bucket names improves readability without wordiness. It's front-loaded and efficient.
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 no output schema, the description sufficiently covers the invocation and expected response: it names the two buckets and their fields. It could add details such as currency or representation of price ranges, but the provided information is enough to understand and apply the result.
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 input schema already fully describes the country parameter with an ISO code and examples, so the description need not add parameter details. The description mentions 'a country' but adds no semantics beyond the schema's 100% coverage. 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 ('Check') and resource ('PikaSim plans cover a country'), and clearly differentiates from siblings by specifying the two return buckets (DATA eSIMs and PHONE-NUMBER eSIMs) with their respective contents. This makes the tool's purpose unambiguous and distinguishes it from general search or pricing tools.
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 implicitly conveys when to use the tool: whenever an agent needs to know which PikaSim plans cover a specific country and wants both data and phone-number options. However, it does not explicitly mention alternatives or conditions where another sibling tool should be preferred, so it lacks explicit exclusions.
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.