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Siima MCP server

Which servers in the official MCP registry are Siima's own, whether they answer, and what they offer. A program checked each of these, nobody copied them from a product page.

read 2026-10-20

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Whose server it is
  • Registry nameonline.siima/esimverified in the MCP registry

The registry name sits under siima.online. The registry only lets a publisher use that namespace after proving control of the domain through DNS or HTTP.

When we asked itchecked 2026-10-20
  • Stateanswerschecked 2026-10-20
  • Tools5
  • Server calls itselfsiima-esim
  • Server version1.0.0
  • Protocol version2025-06-18

On 2026-10-20 the server answered initialize and tools/list without a sign-in. First answer in 567 ms.

Should an agent connect itNot proven either way yet
  • Its tools do every use case we checked: purchase destination data plans ahead of departure; cover several countries on one trip with a regional plan.
  • Checked on 3 of the 7 days it takes to judge reliability.

Once connected

  • For "purchase destination data plans ahead of departure", the likely first call is search_esim_plans.
  • For "cover several countries on one trip with a regional plan", the likely first call is list_regions.
  • create_checkout_link change data without a sign-in: anyone with the address can call them.

Said by rules from the measurements above. The likely first call is a model's pick from the tool list; read its description before relying on it.

Measured dailydaily checks: 3, the first on 2026-10-20
  • INITE MCP scoreafter a weeka score needs 7 daily checks: 3 so far
  • What an agent can do with it2 of 2 use cases
  • Answeredmeasuring3 of the 7 daily checks it takes to print a share
  • Median first answer556 ms
  • Space in an agent's context≈ 1,609 tokensthe definitions of all its tools (5), which an agent carries on every turn
  • Tool definitionsB · 83 of 100
  • Typed results0 of 5 toolsdeclared outputSchema: results come typed, read once
  • Not saying whether it only reads or can destroy: 5 of 5

What an agent can do with it

  • can do · purchase destination data plans ahead of departure
  • not sure · install an eSIM at home before travelling
  • can do · cover several countries on one trip with a regional plan

Each of the product's use cases, put to Jev against this server's tool list: can an agent do it with these tools?

Worth a look

  • Tools that change data, on a server that answers without a sign-in: create_checkout_link

A program checks the server once a day: initialize and tools/list, no model. Tokens are the definitions' length at about four characters a token. The grade averages six checks of every tool's name, description, schema and annotations; it says how well the tools are described, not whether they work. The score weighs what was measured and nothing else: answering (30%), doing the product's job (25%), definitions (20%), context (10%) and use (15%). A part that was not measured is left out, and a hidden instruction caps the score at 40. The state of vendors' MCP servers: method and numbers →

Tools it offers5 tools · read 2026-10-20
  • search_esim_plans

    Search prepaid travel eSIM data plans by destination country (ISO 3166-1 alpha-2, e.g. "JP"), region (e.g. "Europe"), minimum data in GB, maximum total price, or plan duration in days. Plans come in three coverage types: "country" (one…

  • get_esim_plan

    Fetch full details of a single Siima eSIM plan by its id (from search_esim_plans). To buy: call create_checkout_link with the plan id, give the returned URL to the user. They confirm their email with a 6-digit code and pay there; nothing…

  • create_checkout_link

    Create a secure payment link on siima.online for a Siima eSIM plan (Stripe-powered, but hosted on our own site — never a redirect to checkout.stripe.com). Give the returned url to the user to complete payment. Optionally pass the buyer's…

  • list_destinations

    List all countries Siima sells a single-country eSIM plan for, with plan counts and the cheapest total price per country. Country codes are ISO 3166-1 alpha-2. Counts and prices cover country plans only, so they stay comparable — many…

  • list_regions

    List every multi-country coverage area Siima sells — regional areas such as "Europe+", "South East Asia" or "CENAM", and worldwide plans — with the countries every plan in it covers, how many plans it has, and its cheapest total price…

How to connect

Add the server to your MCP client config. Claude Desktop, Cursor and most other clients read this shape:

{
  "mcpServers": {
    "esim": {
      "type": "http",
      "url": "https://api.siima.online/mcp"
    }
  }
}

Add it

Claude Code, in a terminal

claude mcp add --transport http siima https://api.siima.online/mcp

Add to CursorAdd to VS Code

claude.ai, ChatGPT and other clients: add https://api.siima.online/mcp as a custom connector in the settings.

OpenAPI spec

4 paths, read 2026-10-20. Open the spec ↗

Each line is something a program found when it went looking: the registry entry, the server's own answer, a spec that parses. A missing line means we did not find it, not that it does not exist.