Check if a device supports eSIM. Search by device name, model, or vendor (e.g. 'iPhone 15', 'Samsung Galaxy S24', 'Pixel 8'). Optional - useful to verify before purchase.
| Name | Required | Description | Default |
|---|---|---|---|
| query | Yes | Device name, model, or vendor to search (e.g. 'iPhone 15', 'Samsung', 'Pixel') |
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint and idempotentHint, covering the safety profile. The description adds search behavior ('Search by device name, model, or vendor') and example values, but it does not disclose the output format or what a negative match looks like. This is acceptable given annotations carry the main behavioral burden.
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 action and scope. The examples earn their place by clarifying acceptable input formats. The phrase 'Optional - useful to verify before purchase' is slightly vague ('Optional' what?) but still concise and adds usage context. No wasted bulk.
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 single-parameter read-only tool, the description covers what the tool does, what input it accepts, and when to use it. Since there is no output schema, a brief note on what the result indicates would improve completeness, but it is not essential for correct invocation. Overall adequate.
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 description coverage is 100% and the query property is already well-described in the schema. The description adds some extra layering through examples and the phrase 'device name, model, or vendor', but this is mostly redundant with the schema. Baseline 3 applies since the schema does the heavy lifting.
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?
Description uses a specific verb ('check'), clear resource ('device'), and precise scope ('supports eSIM'). It distinguishes itself from siblings like check_coverage or check_order_status by focusing on device capabilities. The examples further disambiguate its domain.
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 phrase 'useful to verify before purchase' gives a concrete when-to-use context. It doesn't explicitly name alternatives or exclusions, but among the sibling tools none overlaps directly, so the guidance is sufficient for an agent to select it appropriately.
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.
Each tool targets a distinct aspect of the eSIM purchasing workflow: coverage, device compatibility, country listing, package search, package details, checkout creation, and order status. There is no overlap between tools.
All tools follow a consistent verb_noun pattern using snake_case (check_, create_, get_, list_, search_). The verbs are specific to the action and nouns describe the resource, creating a predictable pattern.
Seven tools is well within the ideal range for a domain-specific server. Each tool covers a step in the journey from discovery to delivery, with no redundant utilities.
The tool set covers the entire eSIM purchase lifecycle: discovery (list_countries, search_packages, get_package_details), compatibility verification (check_device_compatibility), coverage assessment (check_coverage), payment (create_checkout), and order tracking (check_order_status). No obvious gaps exist for the intended use case.