Mcp MCP Server

@quario/mcp

Let an agent turn JSON data into a PDF, Excel, Word, HTML or CSV report. This MCP server gives Claude and other MCP clients two tools. validate_report checks a report definition, and render_report writes it to a file. One definition renders to all five formats, and the agent gets back a path, never the file's bytes.

• Five formats. One JSON definition renders to pdf, xlsx, docx, html and csv.
• Fixable errors. Each problem names the path it sits at, such as data: expected a JSONPath string. The agent repairs that spot and tries again.
• Files, not bytes. render_report writes to disk and returns the path and size. A report costs the agent one line of context, whatever its size.
• The host stays in charge. Query budgets, link schemes, the data root and the output directory come from the launch configuration. No tool argument changes them.
• No overwrites. A name that exists gets -1, then -2, and so on.
• Local. It runs over stdio, and npx @quario/mcp starts it.

A render_report call and its result:

{
  "definition": {
    "data": "$.orders[*]",
    "detail": { "columns": [{ "header": "Total", "value": "{{ @.price * @.qty }}" }] }
  },
  "target": "pdf",
  "data": { "orders": [{ "price": 250, "qty": 2 }] },
  "filename": "orders"
}

The tool answers Wrote orders.pdf (1.3 kB): /tmp/quario-mcp/orders.pdf.

The server is open source. The engine it runs is not. This package is Apache-2.0. It installs quario and the five render targets. Those packages are commercial software under the Quario License. Evaluation is free. Without a license key, every render carries an unlicensed mark.

Contents

• Getting started
• Configuration
• The trust line
• validate_report
• render_report
• Not in this release
• Development
• License

---

Getting started

1. Check Node. The server needs Node 22 or later.

node --version

2. Add the server to your client. The package carries the engine and the five render targets, so there is nothing else to install.

Claude Code, for evaluation without a key:

claude mcp add quario -- npx -y @quario/mcp

Claude Code, with a license key:

claude mcp add quario -e QUARIO_LICENSE=quario_... -- npx -y @quario/mcp

Claude Desktop, in claude_desktop_config.json:

{
  "mcpServers": {
    "quario": {
      "command": "npx",
      "args": ["-y", "@quario/mcp"],
      "env": { "QUARIO_LICENSE": "quario_..." }
    }
  }
}

Leave out the env line to evaluate without a key.

3. Ask for a report. Restart the client, then ask the agent for one:

Render a PDF of these orders with a product column and a total column: Desk, 250, qty 2.

The agent answers with the path of the file it wrote. The file goes to quario-mcp under the system temp directory unless QUARIO_OUT_DIR says otherwise.

4. Let it read your files (optional). Inline data works everywhere. To let the agent pass a JSON file by dataPath, set QUARIO_DATA_ROOT to the directory that holds it. Claude Code sets CLAUDE_PROJECT_DIR, and the server uses that when QUARIO_DATA_ROOT is unset.

---

Configuration

The server reads its configuration from environment variables. There are no flags and no config file. An empty variable counts as unset.

A value the server cannot run with stops it at startup. The message goes to stderr. That covers a budget that does not parse, a scheme the engine refuses, a data root that does not exist, and an output directory the server cannot create or write. A license key that fails verification is the one exception: the server starts, and the output carries the mark.

The trust line

The configuration the host sets in the environment is the host. The agent that calls the tools is an author, and the engine treats an author as untrusted. So no tool argument reaches a host setting: the query budgets, the href schemes, registered functions, fonts, the license key, the data root and the output directory come from the environment alone.

locale, currency, timeZone and the target options are the exception. They change how a report looks, not what the server can read, run or write, so a call may set them.

---

validate_report

Reads a definition for problems without rendering it.

The definition field carries the full JSON Schema of the report document, descriptions included, so an agent reads the document's semantics from the tool itself. The server reads the envelope against that schema and hands the definition to the engine unchecked. The engine reports a fault as one problem at the path it sits at, which is more use to an agent than the schema's list of every subschema that failed.

A problem is a successful result, never an error. The result carries structuredContent with { problems, warnings }, and one text block with the same object as JSON. Both copies are complete, because one client gives the model the structured copy and another gives it the text.

• A problem is { path, source?, message, code?, start?, end? }. code, start and end come from the located diagnostic when the engine has one.
• A warning is { path, message }.

render_report

Renders a definition to one target and writes the output to a file.

The tool plans the definition against its target, so a required declaration that target loses is a problem. A definition with problems returns the same { problems, warnings } as validate_report, marked isError.

options passes to the target factory. The server refuses fonts and paths. An unknown key returns the factory's own message as an error. The csv target takes no options.

Render data

• Give exactly one of data and dataPath. Both, or neither, is an error.
• dataPath resolves inside the data root. The server tests the path after it resolves symlinks, so a link cannot leave the root. Without a data root, the server refuses dataPath.
• The file holds JSON. A file that does not parse returns the server's own message, and never the file's text.
• An image arrives in one of two forms. { "$image": "assets/logo.png" } names a file inside the data root. { "$base64": "<base64>" } carries the bytes inline. Prefer $image, because a picture in base64 costs the agent's context on every call.
• An object whose only key is $image or $base64 decodes to bytes before the render. This happens at any depth, in inline data and in files alike. The definition reads the bytes as usual: =$.input.logo.
• An $image path resolves against the data root, also inside a dataPath file. The server tests the path after it resolves symlinks. The file must be a PNG or a JPEG. The server reads no other file. A data file reference therefore cannot copy an arbitrary file into a document. Without a data root, the server refuses $image.
• The server reads each file once per call, however many times the data names it.
• A refusal is an error that names its path in the data, such as $.input.logo. That covers a string that is not base64, and an $image that does not exist, leaves the root, or is not an image.

The output file

Every target writes a file and returns its location, never its content.

• The file goes to QUARIO_OUT_DIR.
• filename is a basename. It holds no separator and is not ... The server forces the target's extension. Without a filename, the name is report-<timestamp>.<ext>.
• The server never overwrites. A name that exists gets -1, then -2, and so on.
• The result carries structuredContent with { path, target, bytes }, and the text Wrote <name> (<size>): <absolute path>.

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Not in this release

Registered functions, host fonts, and remote transport.

---

Development

npm run check is the local gate. It runs formatting, lint, the dead-code checks, the size budget, the unit and type suites, and the complexity check. CI runs the same gate. A green check locally means a green pull request.

AGENTS.md holds the conventions for this repo. docs/adr holds the decisions that a reader is most likely to undo.

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License

Copyright 2026 Robin van der Vleuten

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.

The quario and @quario/* packages this server installs have their own license. See the LICENSE file in each of those packages.