🧠 LeetCode MCP

An MCP server that connects your AI coding assistant (Cursor, Claude Code, or any MCP-compatible host) directly to LeetCode — browse problems, get AI coaching, and submit solutions without leaving your editor.

✨ What you can do

| | | |---|---| | 🔍 | Search and read any LeetCode problem with full statement + starter code | | 📅 | Fetch today's daily challenge | | 💡 | Get progressive hints (5 levels — from a nudge to a near-walkthrough) | | 🗺️ | Get a step-by-step conceptual walkthrough without being given the answer | | 🧪 | Review your approach before you code it | | 🐛 | Debug a failing solution with targeted feedback | | 📊 | Analyze the time and space complexity of your code | | 🚀 | Submit a solution and see the result inline | | 📜 | View your full submission history | | 👤 | See your profile and solve counts |

📋 Prerequisites

• Node.js 18 or later
• Cursor, Claude Code, or any MCP-compatible AI host
• A LeetCode account (free tier is fine)

🔌 Setup

Cursor

Add to ~/.cursor/mcp.json:

{
  "mcpServers": {
    "leetcode": {
      "command": "npx",
      "args": ["-y", "leetcode-mcp"]
    }
  }
}

Restart Cursor. Go to Settings → Features → MCP — you should see leetcode listed with a green dot.

Claude Code

claude mcp add leetcode npx -y leetcode-mcp

🔑 Connecting your account

Open an Agent chat and type:

connect my leetcode

The tool will reply with exact instructions — no guessing:

To connect your LeetCode account, grab your session key in 3 steps:

1. Open leetcode.com in your browser and make sure you're logged in
2. Press F12 (or Cmd+Option+I on Mac) to open DevTools
   → Go to Application tab → Cookies → https://leetcode.com
   → Find the row named LEETCODE_SESSION and copy its Value

3. Come back here and say:
   "connect with session key YOUR_VALUE_HERE"

Paste the value and you're done. Sessions last roughly 2 weeks of inactivity — longer if you visit LeetCode regularly in your browser.

🔄 When your session expires

Every tool will tell you clearly:

LeetCode session expired — run 'connect my leetcode' to re-authenticate.

Just follow the same 3 steps again to get a fresh key.

🔍 Checking your connection

check my leetcode status

MCP server: ✓ running
LeetCode:   ✓ logged in as gokhan (session saved 5/28/2026)
Solved:     87 (E:34 M:45 H:8)

🛠️ Tools reference

🔐 Auth tools

| Tool | What it does | |---|---| | connect | Walks you through getting your session key, then saves it | | logout | Clear the saved session | | whoami | Show your username, ranking, and solve counts | | status | Check if the server is running and your session is valid |

🔍 Problem tools

Search for problems

"find medium array problems about sliding window"
"show me 5 easy string problems"
"search for two sum"

Returns: problem ID, title, difficulty, acceptance rate, and the slug you need for other tools.

Read a problem

"get the two-sum problem"
"show me merge-intervals in typescript"
"give me the daily challenge in python"

Returns: full problem statement, constraints, examples, hints, and starter code for your chosen language (or all languages if not specified).

Supported languages: python, python3, java, cpp, c, javascript, typescript, go, rust, swift, kotlin, ruby, scala, php, csharp, dart

Today's daily challenge

"what's the daily challenge?"
"get today's leetcode problem in go"

🧠 AI coaching tools

These use your AI host's model via MCP Sampling — no API key or extra config needed.

💡 Get a hint

"give me a hint for two-sum"
"hint level 2 for longest-substring-without-repeating-characters"
"I'm stuck on coin-change, hint with my current code: [paste code]"

Five progressive levels — start at 1 and work up:

| Level | What you get | |---|---| | 1 | A one-line category nudge ("think about hashing") | | 2 | Which data structure or technique applies and why | | 3 | The key insight that makes the efficient solution possible | | 4 | The algorithm described in plain English, step by step | | 5 | A near-complete walkthrough with edge cases and complexity |

Tip: Start at level 1. Jumping to 5 skips the learning.

🗺️ Step-by-step walkthrough

"walk me through how to think about two-sum"
"explain step by step how to approach coin-change"
"explain the sliding window part of longest-substring-without-repeating-characters"

Covers: how to read the problem, what pattern applies, algorithm construction, edge cases, and complexity. Zero code given.

🧪 Review your approach

"I want to solve two-sum by iterating through all pairs — review my approach"
"my plan for merge-intervals: sort by start time, merge overlapping ones. Is this right?"

Returns: whether your approach is correct, its complexity, edge cases you might miss, and a nudge toward better if one exists.

🐛 Debug your solution

"debug my two-sum solution in python:
  [paste your code]
  it fails with: Expected [0,1] but got [0,0] for input nums=[2,7,11,15], target=9"

Finds the bug, explains why it causes the failure, shows a corrected snippet for the broken section only.

📊 Analyze complexity

"analyze the complexity of my solution in typescript: [paste code]"

Returns: time and space complexity with a trace through the loops, whether this is optimal, and any quick wins.

🚀 Submission tools

Submit a solution

"submit this python solution for two-sum: [paste code]"
"submit my typescript solution for merge-intervals: [paste code]"

Submits to LeetCode, polls until judging is done, and shows the result:

Submission ID: 1234567890
Status:        Accepted
Runtime:       52 ms
Memory:        16.4 MB
Tests:         63 / 63

Or if it fails:

Status:      Wrong Answer
Tests:       42 / 63
Failing Input:
  nums = [3,2,4], target = 6
Expected: [1,2]
Got:      [0,1]

View submission history

"show my recent submissions"
"show my submissions for two-sum"

🎯 Typical workflow

1. "connect my leetcode"               → get session key, paste it back
2. "what's the daily challenge in typescript?"
3. "walk me through how to think about [slug]"
4. "review my approach: [describe your plan]"
5. [write your solution]
6. "hint level 1 for [slug] with my code: [paste]"   ← if stuck
7. "debug my solution: [paste code + error]"          ← if failing
8. "submit this typescript solution for [slug]: [paste code]"
9. "analyze the complexity of my solution: [paste code]"

❓ Troubleshooting

The MCP server doesn't appear in Cursor

• Restart Cursor after editing mcp.json
• Make sure you're using Agent mode in chat, not normal Ask mode

"Session expired" on every tool

• Run "connect my leetcode" and follow the 3 steps to get a fresh key

submit_solution returns "Language not supported"

• Use the slug form: python3 not Python 3, cpp not C++, csharp not C#

AI coaching tools return an error about sampling

• Your host doesn't support MCP sampling. Claude Code and Cursor both do.

📁 Project structure

src/
├── server.ts           — MCP server + all tool definitions
├── auth.ts             — session storage (~/.config/leetcode-mcp/session.json)
├── leetcode-client.ts  — LeetCode GraphQL + REST API client
├── ai-helper.ts        — AI coaching prompts via MCP sampling
└── types.ts            — TypeScript types + language slug map

🔐 Privacy

Your session key is stored locally at ~/.config/leetcode-mcp/session.json and is only sent to LeetCode's own API. AI coaching uses MCP sampling through your host (Cursor, Claude Code) — no third-party services involved.