An MCP (Model Context Protocol) server that lets AI assistants such as Claude Desktop, Claude Code and Cursor fill PDF forms through the FillWise API (POST /api/v1/pdf/fill). Runs over stdio.

Tools:

fill_pdf: takes a PDF path on disk, source text and optional attachments, writes the filled PDF next to the original (<name>.filled.pdf by default).
fill_pdf_base64: same, but takes the PDF as base64 and returns base64. For clients without filesystem access.

Both work with AcroForm PDFs (real form fields, mode: acroform) and digital flat PDFs (no fields, values are drawn at computed positions, mode: flat). Scanned PDFs without a text layer are rejected. Review the result before using it, especially in flat mode.

Limits (set by the API): PDF up to 14 MB, data up to 60000 characters, up to 4 attachments (jpeg, png, webp or pdf, up to 5 MB each), pages as a string like "1, 3-6".

Requirements

Node.js 18 or newer.
A FillWise API key. Create one at https://fillwise.ai/account, section "API keys". Fills made through the API spend the account's regular fill quota.

Install and run

From npm (published, https://www.npmjs.com/package/fillwise-mcp):

npx -y fillwise-mcp

From this repository:

cd mcp && npm install
FILLWISE_API_KEY=fw_live_... node mcp/src/index.js

Environment variables:

FILLWISE_API_KEY (required)
FILLWISE_API_URL (optional, default https://fillwise.ai)

Claude Desktop

Add to claude_desktop_config.json (Settings, Developer, Edit Config):

{
  "mcpServers": {
    "fillwise": {
      "command": "npx",
      "args": ["-y", "fillwise-mcp"],
      "env": { "FILLWISE_API_KEY": "fw_live_..." }
    }
  }
}

Running from a local checkout instead: "command": "node", "args": ["/absolute/path/to/fillwise_app/mcp/src/index.js"].

Claude Code

claude mcp add fillwise -e FILLWISE_API_KEY=fw_live_... -- npx -y fillwise-mcp

Cursor

Add to .cursor/mcp.json in the project (or ~/.cursor/mcp.json globally):

{
  "mcpServers": {
    "fillwise": {
      "command": "npx",
      "args": ["-y", "fillwise-mcp"],
      "env": { "FILLWISE_API_KEY": "fw_live_..." }
    }
  }
}

Example prompt

"Fill /Users/me/forms/w9.pdf with the data from /Users/me/forms/company-profile.txt" or paste the details directly: "Fill /Users/me/forms/w9.pdf: JLH Associates LLC, 123 Main St, Trenton NJ 08601, EIN 12-3456789".

Errors

The tools return plain messages for the API error codes: missing or invalid key (401), scanned PDF (422), spent quota or rate limit (429), AI provider failure (502, the fill is not charged).

Publishing (npm and the official MCP Registry)

package.json carries mcpName and server.json describes the server for the official registry (registry.modelcontextprotocol.io), from which PulseMCP and Glama build their listings. Bump the version in package.json, server.json (twice) and src/index.js together, then:

cd mcp
npm publish --access public                 # needs `npm login` as the package owner
mcp-publisher login github                  # as filipp-nekahev: owns io.github.filipp-nekahev/*
mcp-publisher publish                       # versions are immutable once published

mcp-publisher is a single binary from https://github.com/modelcontextprotocol/registry/releases (mcp-publisher validate checks server.json without publishing).