Use in ToolGate

In the ToolGate console, open Server packages, then Marketplace, and install this package. These values identify exactly what you install:

{
    "marketplace": "olo-labs-marketplace",
    "packageId": "examples.downloads",
    "version": "0.1.0",
    "packageDigest": "sha256:c257c9f6cadf7a79ac7e69714d0ebf7fb00217b96cf17c90160bdcfd10043c15"
}

Overview

File download

Tools: downloads.fetch. Part of the Java Tool SDK examples.

Downloads <folder>/<file> from the file server the administrator approved into a local directory, and returns where it landed: the absolute path, a file: URL, a shared URL when the directory is published (for example behind a web server or a file share), the size and the SHA-256.

Safety

There is no URL argument. The server is the DownloadHost setting and the route allows only /<folder>/<file>, each a plain name, so a model cannot reach other hosts or internal services.
Downloads are capped at 32 MiB (maxResponseBytes on the route) and 50 s.
The file is written to a temporary file and moved into place atomically, under a validated name, and never replaces an existing file unless overwrite is true.
Under ToolGate the Tool Host's broker makes the request; add @HttpAuth to the route if the server needs credentials.

Settings

Globals unless marked. Set them in toolgate.dev.json for development, as TOOLGATE_GLOBAL_<NAME> (or TOOLGATE_DESTINATION_<NAME>, TOOLGATE_SECRET_<NAME>) for a standalone jar, or on the deployment under ToolGate.

Setting	Default	Meaning
`DownloadHost` (destination)	none	Host of the file server, such as `files.example.com`. HTTPS on 443.
`DownloadDir`	`downloads`	Directory files are saved in. Absolute under a Tool Host.
`PublicBaseUrl`	`none`	URL at which `DownloadDir` is shared, such as `https://files.example.com/incoming/`.

Your server lays files out deeper than one folder? Add a route for that shape, such as /{a}/{b}/{file}, and list it in the tool's routes. A route is part of the tool's descriptor, so an administrator approves any change.

Try it

cp toolgate.dev.example.json toolgate.dev.json   # then edit it; never commit toolgate.dev.json
toolgate dev                                      # an MCP server over stdio
toolgate pack                                     # build/toolgate/file-download-0.1.0.tgpkg

Things to ask a model connected to it:

"Download reports/2026-10.csv and give me the link."
"Fetch builds/app-1.4.2.zip again, replacing the old copy."

Source repository
License: Apache-2.0

Tools

downloads.fetch Idempotent: Download a file Downloads <folder>/<file> from the approved file server into the download directory and returns its local path, file URL, shared URL, size and SHA-256.

Settings it needs

Name	Kind	Type	Default	Description
`DownloadHost`	destination			Host of destination file-server
`DownloadDir`	global	STRING	`downloads`	Directory downloaded files are saved in. Use an absolute path under a Tool Host.
`PublicBaseUrl`	global	STRING	`none`	URL at which DownloadDir is shared, such as https://files.example.com/downloads/, or none.

Versions

Version	API change	Compatibility	Published
0.1.0	none	Java 17, protocol 2	15 Oct 2026 - 11:55

Publisher

ToolGate Examples, OLO Labs

Publisher details are supplied by the publisher. Validation checks package format, not code safety.

Download a file - ToolGate tool package