Claude fill PDF: Instafill.ai MCP integration
Use Claude to fill out PDF forms directly from the chat. Connect Instafill.ai to Claude.ai, Claude Desktop, or Claude Code CLI and ask Claude to find, fill out, and download your forms - without leaving the conversation.
What This Integration Does
If you have ever searched for how to fill out a PDF with Claude, this is the answer. Instafill.ai connects to Claude through MCP (Model Context Protocol) - an open standard that lets AI assistants securely access external tools and data. Once connected, Claude has direct access to your Instafill.ai workspace: your forms, your fill history, predefined profiles, etc.
Instead of opening a PDF manually, copying field names, and entering data by hand, you describe what you need in plain language and Claude handles the rest. You can fill out PDF forms with Claude AI across three clients - Claude.ai (web and mobile), Claude Desktop (Windows and macOS), and Claude Code CLI.
Once connected, you can ask Claude things like:
- "I want to upload a new form"
- "Show me all forms available in my workspace"
- "Fill out the CMS-1500 claim form with my patient's information"
- "Find the prior authorization form and fill it out using my saved profile"
- "Download the completed form from my last session"
Claude finds the right form, fills it out using the data you provide, sources attached or saved profiles, and returns a download link when it is done.
Before You Start
You need:
- A Claude account - Claude.ai, Claude Desktop, or Claude Code CLI
- An Instafill.ai account - you can create one for free during the setup flow
No developer mode required. No extra configuration needed.
Setup: Choose Your Claude Client
Option 1 - Claude.ai (Web and Mobile)
Best for: everyday form filling tasks, users who work in a browser or on mobile, and teams that do not want to install additional software.
Steps:
- Go to claude.ai/customize/connectors
- Click the + icon, then click Add custom connector
- In the "Remote MCP server URL" field, enter:
https://mcp.instafill.ai/mcp - Save the connector and click Connect
- Sign in to your Instafill.ai account, select your workspace, and approve permissions
The connection is live. Go back to any Claude.ai conversation and start asking questions.
Option 2 - Claude Desktop
Best for: users who prefer a native desktop application, workflows that involve local files, and anyone who wants Instafill.ai accessible without keeping a browser tab open.
Claude Desktop is Anthropic's standalone application for Windows and macOS. Connecting Instafill.ai to Claude Desktop means you can fill out PDF forms from your desktop environment - particularly useful if you are already working with local PDF files and do not want to switch to a browser.
Steps:
- Open Claude Desktop and navigate to Settings > Connectors
- Click Add Custom Connector
- In the "Remote MCP server URL" field, enter:
https://mcp.instafill.ai/mcp - Click Connect and follow the OAuth flow to sign in to your Instafill.ai account
- Select your workspace and approve permissions
Once connected, Instafill.ai tools are available in all your Claude Desktop conversations.
Full instructions are in the Instafill.ai MCP Server Documentation.
Option 3 - Claude Code CLI
Best for: developers, technical teams, and anyone who wants to automate form filling as part of a larger workflow or integrate it into scripts and pipelines.
Claude Code is Anthropic's command-line tool for working with Claude in a terminal environment. Connecting Instafill.ai to Claude Code lets you trigger form fill jobs programmatically, chain them with other operations, and build automated document workflows without a graphical interface.
This is the right option if you want to do things like:
- Automatically fill out forms as part of a data processing pipeline
- Integrate Instafill.ai into a development or deployment workflow
- Run batch fill jobs from the terminal without opening a browser
- Test and build custom integrations against the Instafill.ai MCP tools
Steps:
- Install Claude Code CLI if you have not already - see the Claude Code documentation
- Run this command in your terminal:
claude mcp add --transport http instafill https://mcp.instafill.ai/mcp - Launch Claude Code in your project directory:
claude - Use the
/mcpcommand to view connected MCP servers and authenticate:/mcp - Select "Authenticate" when prompted and complete the OAuth flow in your browser
Once authenticated, Instafill.ai tools are available through natural language inside Claude Code, just like in Claude.ai.
How to Fill Out PDF Forms with Claude
Once the connector is active, filling out a PDF form is a conversation. Here are some examples of how to use it.
Browse your forms:
"List all my forms" "Find the I-9 form" "Show me all my filled forms from this week"
Fill out a form:
"Fill out the prior authorization form with the following patient details: ..." "Fill out the CMS-1500 form using my saved profile for Dr. Smith's practice"
Claude fills out the form using the data you provide in the conversation. Your data goes directly to Instafill.ai servers - it is not stored in your Claude conversation history.
Track and download:
"Is my form ready?" "Download the completed form"
Claude checks the status and returns a download link when the fill is complete. Download links are valid for 10 minutes.
Manage profiles:
"Create a new profile" "Show me my saved profiles"
What Claude Can Do with Your Instafill.ai Workspace
The integration gives Claude access to 16 tools across your workspace:
| What you can do | How to ask Claude |
|---|---|
| See all form templates | "List my forms" |
| Find a specific form | "Find the CMS-1500 form" |
| See completed fill jobs | "Show my filled forms" |
| Fill out a form | "Fill out the prior auth form with my patient data" |
| Check fill status | "Is my form ready?" |
| Download a filled form | "Download the completed form" |
| Upload a new form | "I want to upload a new form" |
| Create a profile | "Create a new profile" |
| View saved profiles | "Show me my saved profiles" |
Use Cases
ABA Therapy and Behavioral Health
ABA practices deal with high documentation volume every day - session notes, progress reports, prior authorizations, CMS-1500 claims, and insurance packets. Most of these are the same forms filled out with different client data each time.
With Claude connected to Instafill.ai, a BCBA or office staff member can paste session notes directly into the chat and ask Claude to fill out the right form from them. No switching between the patient record, the PDF, and the billing system - everything happens in one conversation.
For example:
"Here are today's session notes for patient John D. Fill out the CMS-1500 claim form using this information: [type or paste notes]"
Claude fills out the form and returns a download link in seconds.
Healthcare and Medical Practices
Credentialing packets are one of the most time-consuming forms of paperwork in healthcare - the same provider information repeated across 20 to 30 pages for different insurers or facilities.
With Instafill.ai, you upload the provider's CV, license documents, and any supporting files once. Then ask Claude to fill out the credentialing packet using those uploaded documents as the source. It reads across multiple file formats - PDF, DOCX, TXT - and maps the right information to the right fields automatically.
"Fill out the CAQH credentialing form using the documents I just uploaded"
Legal Practices and Immigration Attorneys
Immigration attorneys work with the same client data across multiple USCIS forms - I-485, I-131, I-765, G-1145 - often in the same case. Rather than re-entering the same information for each form, staff can upload the client's source documents once and ask Claude to fill out each form from them in sequence.
"Fill out form I-765 using the client intake document I uploaded"
The same uploaded source works across multiple fill jobs. No re-uploading, no re-entering.
HR and Operations Teams
Onboarding paperwork involves forms that rarely change but need to be filled out fresh for every new hire. HR staff can type the employee's details directly into the Claude conversation and ask Instafill.ai to fill out the relevant forms on the spot - I-9 verifications, state tax forms, direct deposit authorizations - without building any templates or profiles in advance.
"New hire: Jane Smith, SSN ending 4521, start date May 1. Fill out the I-9 and the state withholding form"
Construction and Contracting
Prequalification packets and subcontractor agreements often run to dozens of pages. Rather than filling them out manually or maintaining templates, project teams can upload the company's existing capability statement or past project list as a source document and ask Claude to fill out any new prequalification form from it.
"Fill out this prequalification packet using our company capability statement PDF"
The source document stays on file in Instafill.ai and can be reused for every new packet that comes in.
How Claude Differs from ChatGPT for PDF Form Filling
Both Claude and ChatGPT connect to the same Instafill.ai MCP server and have access to the same 16 tools. The main difference is how you provide your form data:
- With Claude - you provide your data directly in the conversation. Claude reads it and passes it to Instafill.ai. This makes the flow faster and more conversational.
- With ChatGPT - data is entered through a secure widget that opens outside the chat. This keeps the data out of the conversation history, which some users prefer for sensitive information.
Both approaches are secure. Your data is transmitted directly to Instafill.ai servers and is not retained by either AI assistant.
If you want to connect ChatGPT instead, see Connect Instafill.ai to ChatGPT with MCP.
Common Questions
Do I need a paid Claude plan?
No. A free Claude account is enough to connect Instafill.ai via MCP.
Which Claude client should I use?
If you just want to fill out forms without any technical setup, use Claude.ai - it works in your browser and on mobile. If you prefer a native app experience, use Claude Desktop. If you are a developer or want to automate form filling as part of a pipeline, use Claude Code CLI.
Is my data secure when I fill out forms through Claude?
Yes. The OAuth flow means Claude never sees your Instafill.ai password. Data you share in the conversation is passed directly to Instafill.ai servers. It is not stored in your Claude conversation history after the session. Learn more at Instafill.ai Security.
Can I use saved profiles with Claude?
Yes. You can ask Claude to use any saved profile from your workspace - "Fill out this form using my saved profile for [name]" - and Claude will pass the profile data to Instafill.ai automatically.
What happens if Claude cannot find my form?
Ask Claude to list all your forms first. If the form is not listed, it may not be uploaded to your workspace yet. Ask Claude to upload a new form and follow the link it provides.
Can I revoke Claude's access to my Instafill.ai workspace?
Yes. You can revoke access at any time by removing the connector from Claude's settings page.