SimFuse eSIM Storefront

List eSIM destinations

list-destinations

Read-onlyIdempotent

Find the countries SimFuse sells eSIMs for, with the cheapest plan price ("from" price) for each in the currency you ask for. Start here when someone names a place: it turns "Portugal" into the two-letter country code the other tools take, and shows what that destination starts at. For one destination, follow it with list-plans; for a trip covering two or more countries, use plan-trip instead. Read-only, and it answers from the SimFuse catalog alone.

Tool call template

This tool declares no required parameters. Add optional parameters from the input schema as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {},
    "name": "list-destinations"
  }
}

Input Schema

Name	Required	Description
`limit`	No	Optional. Maximum destinations to return, 1 to 300. Defaults to 300, which is the whole list.
`search`	No	Optional. Match destinations by name, ISO 3166-1 alpha-2 or alpha-3 code, case-insensitively. A partial name works: "port" matches Portugal. Omit to list every destination.
`currency`	No	Optional. ISO 4217 three-letter code the "from" prices are quoted in, e.g. "USD", "EUR", "GBP". Defaults to EUR. An unknown code falls back to EUR rather than failing.

Output Schema

Name	Required	Description
`total`	Yes	How many destinations matched, before `limit` was applied.
`currency`	Yes	ISO 4217 code every from_price_cents below is quoted in, e.g. "EUR".
`returned`	Yes	How many destinations are in this response.
`destinations`	Yes	The matching destinations. Empty when nothing matched.

Schema Changelog

Changes observed during successful MCP inspections.

First observedNov 7, 2026

TDQS

A4.5/5.0

Behavior4/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint, idempotentHint, and openWorldHint=false, so the safety profile is covered; the description adds substantive behavior by explaining that prices are the cheapest available plan per destination and that this tool performs the human-name → ISO alpha-2 code translation the other tools depend on. The "answers from the SimFuse catalog alone" line largely restates openWorldHint=false and the read-only claim restates readOnlyHint, which keeps it from a 5, but the price-derivation and code-mapping context is genuine added value.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Front-loads what the tool returns before any routing advice, then moves to alternatives and scope. Four short sentences, each carrying distinct information (purpose, entry condition, sibling routing, data source), with no redundancy.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

An output schema exists, so return values need not be explained, and all three parameters are fully documented in the schema. What remains for the description — when to reach for this versus list-plans, plan-trip, or get-destination-info, and that the data is catalog-only — is fully covered.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100% and all three parameters (limit, search, currency) carry min/max, defaults, and format notes, so the schema does the heavy lifting. The description only lightly gestures at currency ("in the currency you ask for") and alludes to name matching via the Portugal example, but adds no syntax or semantics the schema lacks — the baseline of 3 applies.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb (find/list) and resource (countries SimFuse sells eSIMs for) plus the payload (cheapest "from" price per destination in a requested currency). It explicitly distinguishes itself from the two most confusable siblings — list-plans for a single destination and plan-trip for multi-country trips — so an agent can route without opening any schema.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines5/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

Gives an explicit entry condition ("Start here when someone names a place") and a concrete disambiguation rule: one destination → list-plans, two or more → plan-trip. The when-to-use is stated positively and the alternatives are named with the condition that selects them.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

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