MCP LinkedIn Poster (TypeScript)

An MCP (Model Context Protocol) server that allows ChatGPT / Claude Desktop to post content to LinkedIn using the official LinkedIn UGC Posts API and an OAuth 2.0 access token.

This server runs locally and is designed to be registered in your ChatGPT / Claude MCP server settings.

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What this does

• Runs an MCP server over stdio
• Accepts post requests from ChatGPT / Claude
• Publishes text posts to your LinkedIn profile
• Uses LinkedIn OAuth (3-legged) authentication
• Reads secrets securely via environment variables

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Project structure

mcp-linkedin-poster/ ├─ src/ │ └─ index.ts # main MCP server (TypeScript source) ├─ dist/ │ └─ index.js # compiled output (what Node actually runs) ├─ .env # environment variables (DO NOT COMMIT) ├─ package.json ├─ tsconfig.json └─ README.md

yaml Copy code

What is dist?

dist stands for distribution.
It contains the compiled JavaScript output generated from TypeScript.

You edit src/index.ts
You run dist/index.js

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Install

npm install
Build
Compile TypeScript → JavaScript:

bash
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npx tsc
This generates:

bash
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dist/index.js
Run locally (sanity check)
bash
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node dist/index.js
If environment variables are missing you will see:

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Missing env LINKEDIN_ACCESS_TOKEN
Missing env LINKEDIN_AUTHOR_URN
That is expected until setup is complete.

Environment variables (.env)
Create a file named .env in the project root:

env
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LINKEDIN_ACCESS_TOKEN=
LINKEDIN_AUTHOR_URN=
LINKEDIN_VERSION=202502
What each variable is
Variable	Description
LINKEDIN_ACCESS_TOKEN	OAuth 2.0 member access token from LinkedIn
LINKEDIN_AUTHOR_URN	Your LinkedIn profile URN (urn:li:person:...)
LINKEDIN_VERSION	LinkedIn API version header (optional, safe to keep)

⚠️ Never commit .env
Add it to .gitignore.

How to get LINKEDIN_ACCESS_TOKEN
Go to https://www.linkedin.com/developers/

Open your LinkedIn app

Use OAuth 2.0 → Token Generator

Select scope:

w_member_social (required for posting)

Generate token

Copy it as a single line

Paste into .env:

env
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LINKEDIN_ACCESS_TOKEN=PASTE_TOKEN_HERE
How to get LINKEDIN_AUTHOR_URN
Method (recommended): LinkedIn userinfo endpoint
Curl
bash
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curl -X GET "https://api.linkedin.com/v2/userinfo" \
  -H "Authorization: Bearer YOUR_ACCESS_TOKEN" \
  -H "Content-Type: application/json"
Example response:

json
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{
  "sub": "8qD1tr1-1m",
  "name": "Your Name"
}
Your author URN becomes:

env
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LINKEDIN_AUTHOR_URN=urn:li:person:8qD1tr1-1m
Windows PowerShell version
powershell
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$token="YOUR_ACCESS_TOKEN"
Invoke-RestMethod `
  -Uri "https://api.linkedin.com/v2/userinfo" `
  -Headers @{ Authorization = "Bearer $token" }
Example: LinkedIn post via curl (UGC API)
bash
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curl -X POST "https://api.linkedin.com/v2/ugcPosts" \
  -H "Authorization: Bearer YOUR_ACCESS_TOKEN" \
  -H "X-Restli-Protocol-Version: 2.0.0" \
  -H "Content-Type: application/json" \
  -d '{
    "author": "urn:li:person:YOUR_PERSON_ID",
    "lifecycleState": "PUBLISHED",
    "specificContent": {
      "com.linkedin.ugc.ShareContent": {
        "shareCommentary": { "text": "Hello from MCP 🚀" },
        "shareMediaCategory": "NONE"
      }
    },
    "visibility": {
      "com.linkedin.ugc.MemberNetworkVisibility": "PUBLIC"
    }
  }'
A 201 Created response means success.

Registering this server in ChatGPT / Claude MCP
Add this to your MCP config:

json
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{
  "mcpServers": {
    "linkedin_poster": {
      "command": "node",
      "args": [
        "C:\\Users\\User\\Desktop\\mcp-linkedin-poster\\dist\\index.js"
      ],
      "env": {
        "LINKEDIN_ACCESS_TOKEN": "PASTE_TOKEN_HERE",
        "LINKEDIN_AUTHOR_URN": "urn:li:person:PASTE_ID_HERE",
        "LINKEDIN_VERSION": "202502"
      }
    }
  }
}
Restart ChatGPT / Claude Desktop after saving.

Common errors & fixes
❌ Missing env LINKEDIN_ACCESS_TOKEN
.env not created

MCP config missing env

Token pasted with line breaks

❌ Invalid OAuth 2.0 Access Token (code 190)
Token expired

Wrong app

Missing w_member_social scope

Regenerate token.

❌ PowerShell header error
Use a hashtable, not a string:

powershell
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-Headers @{ Authorization = "Bearer $token" }
❌ Node cannot find dist/index.js
Run commands from the project root, not src/.

Correct:

bash
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node dist\index.js
Wrong:

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node src\dist\index.js
Security notes
Treat LinkedIn tokens like passwords

Do not commit secrets

Prefer MCP environment injection over .env in production
**
for CLAUDE

    "linkedin_poster": {
      "command": "node",
      "args": [
        "C:\\Users\\User\\Desktop\\mcp-linkedin-poster\\dist\\index.js"
      ],
      "env": {
        "LINKEDIN_ACCESS_TOKEN": "",
        "LINKEDIN_AUTHOR_URN": "urn:li:person:",
        "LINKEDIN_VERSION": "202502"