MCP tools

The MCP server at https://mcp.tmphost.io/mcp has one tool, file, with four actions: upload, download, get and url.

LLM-friendly version (Markdown): https://tmphost.io/docs/mcp.md

When to use MCP

Every byte of a file passes through the model's context as a tool argument or result. If the agent can run shell commands, the CLI uploads from disk instead and keeps large files out of the context. Use MCP when there is no shell, or for small files the agent has just written.

For text files (.html, .css, .js, .md, .json, .svg, .txt) set format to textContent and send the text as is. It is a third smaller than base64 and stays readable. Use base64Content only for binary files.

Connect

The server speaks streamable HTTP. Add it to any MCP client; clients that support OAuth open the browser to sign in through app.tmphost.io the first time they connect.

MCP client config (JSON)

{
  "mcpServers": {
    "tmphost": {
      "type": "http",
      "url": "https://mcp.tmphost.io/mcp"
    }
  }
}

Claude Code

$ claude mcp add --transport http tmphost https://mcp.tmphost.io/mcp

Arguments

Argument	Description
action	Required. `upload`, `download`, `get` or `url`.
id	Folder id. `upload` without it creates a new folder; with it, adds or replaces files in that folder. Required by the other actions.
ttl	Lifetime of a new folder in whole minutes, such as `30m` or `2h` (default `30m`). `upload` only, and only without `id`.
fileName	File name, without directories, such as `index.html`.
path	Directory inside the folder, such as `site/css`, at most 5 levels. Empty for the folder root.
format	Which field carries the content: `base64Content` (default) or `textContent`. `upload` and `download` only.
textContent	UTF-8 text content, as is. `upload` with `format: "textContent"`.
base64Content	Base64 content. `upload` with `format: "base64Content"`.

Result fields

Each action fills its part; empty fields are left out.

Field	Description
id	The folder id. Keep it to add files later.
url	Public URL of the file (`upload`), the folder (`get`) or what `url` asked for.
expiresAt	When the folder is deleted, RFC 3339 in UTC. `upload` returns it only for a new folder.
fileName, path, size	The file's name, directory and size in bytes.
creditsSpent	Credits the upload cost.
textContent, base64Content	The downloaded file, in the field `format` named.
files	`get`: every file as `fileName`, `path`, `size`, `url`.

Examples

The ids, times and URLs below are examples; take the real ones from each result.

Upload an HTML page as text, in a new folder

Call file

{
  "action": "upload",
  "ttl": "2h",
  "fileName": "index.html",
  "format": "textContent",
  "textContent": "<!doctype html><title>Report</title><link rel=\"stylesheet\" href=\"css/style.css\"><h1>Q3 report</h1>"
}

Result

{
  "id": "k7q2m9xa",
  "url": "https://k7q2m9xa.file.tmphost.io/index.html",
  "expiresAt": "2026-10-19T23:08:00Z",
  "fileName": "index.html",
  "size": 98,
  "creditsSpent": 4
}

A file under 1 MB in a 2 hour folder costs 1 × 4 = 4 credits. Because index.html is at the root, the folder URL https://k7q2m9xa.file.tmphost.io/ serves the page too.

Add a stylesheet to the same folder, in a directory

Call file

{
  "action": "upload",
  "id": "k7q2m9xa",
  "path": "css",
  "fileName": "style.css",
  "format": "textContent",
  "textContent": "body{font:16px/1.5 system-ui;margin:40px}"
}

Result

{
  "id": "k7q2m9xa",
  "url": "https://k7q2m9xa.file.tmphost.io/css/style.css",
  "fileName": "style.css",
  "path": "css",
  "size": 41,
  "creditsSpent": 4
}

With id, leave out ttl: the folder keeps its expiry, and the cost counts its remaining lifetime.

Upload an image as base64

Call file

{
  "action": "upload",
  "id": "k7q2m9xa",
  "path": "img",
  "fileName": "logo.png",
  "base64Content": "iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAADUlEQVR42mNkYPhfDwAChwGA60e6kgAAAABJRU5ErkJggg=="
}

Result

{
  "id": "k7q2m9xa",
  "url": "https://k7q2m9xa.file.tmphost.io/img/logo.png",
  "fileName": "logo.png",
  "path": "img",
  "size": 70,
  "creditsSpent": 4
}

format defaults to base64Content, so it can be left out here.

Replace a file in place

Upload to the same id, path and fileName again. The URL stays https://k7q2m9xa.file.tmphost.io/index.html, so a link already shared shows the new version.

Call file

{
  "action": "upload",
  "id": "k7q2m9xa",
  "fileName": "index.html",
  "format": "textContent",
  "textContent": "<!doctype html><title>Report</title><link rel=\"stylesheet\" href=\"css/style.css\"><h1>Q3 report (final)</h1>"
}

List a folder's files

Call file

{ "action": "get", "id": "k7q2m9xa" }

Result

{
  "id": "k7q2m9xa",
  "url": "https://k7q2m9xa.file.tmphost.io/",
  "expiresAt": "2026-10-19T23:08:00Z",
  "files": [
    { "fileName": "style.css", "path": "css", "size": 41, "url": "https://k7q2m9xa.file.tmphost.io/css/style.css" },
    { "fileName": "logo.png", "path": "img", "size": 70, "url": "https://k7q2m9xa.file.tmphost.io/img/logo.png" },
    { "fileName": "index.html", "path": "", "size": 106, "url": "https://k7q2m9xa.file.tmphost.io/index.html" }
  ]
}

Get a URL

The URL of a folder (id), a directory (id, path, ending with /) or a file (id, fileName, optional path). The file does not have to exist yet.

Call file

{ "action": "url", "id": "k7q2m9xa", "path": "img", "fileName": "logo.png" }

Result

{
  "id": "k7q2m9xa",
  "url": "https://k7q2m9xa.file.tmphost.io/img/logo.png",
  "expiresAt": "2026-10-19T23:08:00Z",
  "fileName": "logo.png",
  "path": "img"
}

Download a text file

Call file

{ "action": "download", "id": "k7q2m9xa", "path": "css", "fileName": "style.css", "format": "textContent" }

Result

{
  "id": "k7q2m9xa",
  "fileName": "style.css",
  "path": "css",
  "size": 41,
  "textContent": "body{font:16px/1.5 system-ui;margin:40px}"
}

A download as textContent fails for a file that is not UTF-8 text; download it with format: "base64Content" instead.

Errors

A failed call returns an error message that says what to change:

Message	Fix
textContent needs format textContent	Add `"format": "textContent"`, or send `base64Content`.
base64Content must be base64	Send standard base64, or the text itself as `textContent`.
ttl only applies to a new folder: leave out id or ttl	A folder's expiry is set when it is created.
ttl must be whole minutes, such as 30m or 2h	Use a duration like `45m` or `6h`.
fileName is required and must not contain /	Put directories in `path`.
the file is not UTF-8 text: download it with format base64Content	Use `base64Content` for binary files.