Harpy 🦅

A CLI toolkit and Model Context Protocol (MCP) server for competitive programming. Converts problem statements into decoupled C++ templates, runs brute-force differential testing to eliminate AI test-case hallucination, and synchronizes test cases directly with CPH and local compilers.

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✨ Features

• 📑 Decoupled Code Templates: Converts problem descriptions into clean, typed solve(...) function templates with fast I/O in main(), separating I/O parsing from core algorithmic logic.
• ⚡ Instant Scaffolding & Background Test Synthesis: Scaffolds starter code, problem specifications, and CPH files in <200ms, while synthesizing and verifying edge/stress test cases in the background via detached processes (--async).
• 🎯 Brute-Force Differential Testing & Batch Oracle: Eliminates AI test-case hallucination. Runs a simple brute-force Python script locally across edge cases, boundary conditions ($N=0, 1$, negative numbers), and randomized stress tests to generate 100% verified expected outputs in a single batched process.
• ⚡ Competitive Programming Helper (CPH) Sync:
  • Live HTTP dispatch to VS Code / Antigravity CPH extension on port 27121.
  • Generates native .cph/ .prob files directly for offline use.
• 🧪 Fast Local Test Runner (harpy test):
  • Compiles C++ (g++ -O3 -std=c++17), Python, and Java.
  • Formats results with color-coded tables, execution time, and side-by-side failure diffs.
• 🤖 Universal Model Context Protocol (MCP) Server:
  • Exposes deterministic tools (setup_problem, oracle_generate_tests, sync_cph, test_solution) for coding agents in VS Code, Antigravity, Cursor, Windsurf, Claude Desktop, and Zed.
• 🔇 Distraction-Free Workspace: Auto-configures .tabignore to silence intrusive inline AI autocomplete while you code algorithms.

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🚀 Quickstart

1. Installation

Option A: 1-Command Installer (Recommended — Zero Python needed, auto-configures PATH)

• Linux & macOS:

  curl -fsSL https://raw.githubusercontent.com/Seronic2001/harpy/master/install.sh | bash
  

• Windows (PowerShell):

  irm https://raw.githubusercontent.com/Seronic2001/harpy/master/install.ps1 | iex
  

Option B: Via pip

pip install harpy-cp

Note: If harpy is not recognized immediately in your terminal due to PATH settings, you can run any Harpy command directly using:

python -m harpy setup-ai    # or 'py -m harpy setup-ai' on Windows

To upgrade Harpy:

pip install --upgrade harpy-cp

2. Configure AI & Shell Completion (1-Command Setup)

# Auto-installs Antigravity skill & registers Harpy MCP server
harpy setup-ai

# Enable fast tab-completion for problem slugs and solutions
harpy completion install

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💻 CLI Usage

Initialize a DSA Workspace

In any folder where you want to practice problems (e.g. ~/dsa-prep):

mkdir -p ~/dsa-prep && cd ~/dsa-prep
harpy init

What harpy init sets up:

• Scaffolds a problems/ directory.
• Configures .tabignore and .antigravityignore so inline ghost AI suggestions don't distract you while solving problems.

Create & Scaffold Problems (1-Command Setup)

Create a categorized problem workspace, run reference oracle test verification, and sync to CPH in a single command:

# Instant scaffolding (<0.2s) with detached background test synthesis
harpy create -s spec.json --async

# Or wait synchronously for test generation and verification
harpy create -s spec.json --sync

# Or pipe specification directly via stdin
cat spec.json | harpy create - --async

# Quick flag-based setup
harpy create --title "Two Sum" --category "sorting-and-searching" --difficulty "Easy"

Synthesize Additional Tests / Stress Test

# Run algorithmic test generator and verify with reference oracle
harpy generate-tests problems/two-sum

# Or run in the background with alias
harpy stress problems/two-sum -b

Test Solutions Locally

# Auto-resolves problem slugs and files inside problems/
harpy test lexicographically-minimal-walk

# Or direct file paths
harpy test problems/two-sum/solution.cpp

Output:

⚡ Harpy Test Runner: Testing solution.cpp (cpp)
            Test Results             
┏━━━━━━━━┳━━━━━━━━┳━━━━━━━━┳━━━━━━━━┓
┃ Case # ┃  Type  ┃ Status ┃   Time ┃
┡━━━━━━━━╇━━━━━━━━╇━━━━━━━━╇━━━━━━━━┩
│   01   │ sample │ ✔ PASS │ 2.7 ms │
│   02   │ sample │ ✔ PASS │ 3.0 ms │
│   03   │ edge   │ ✔ PASS │ 2.9 ms │
│   04   │ stress │ ✔ PASS │ 5.1 ms │
└────────┴────────┴────────┴────────┘
✨ All 4 test cases passed!

Push to CPH Extension

Push problem metadata and test cases to your active CPH listener in VS Code or Antigravity:

harpy push problems/maximum-subarray-sum

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🛠️ IDE Setup Guide

Harpy connects to any editor via two open standards:

1. Model Context Protocol (MCP): Lets AI assistants formulate problems, run brute-force differential testing, and execute test runners.
2. CPH Protocol & .cph/ Files: Integrates directly with the Competitive Programming Helper extension.

IDE Compatibility Matrix

IDE / Editor	AI Assistant (MCP)	CPH GUI Test Runner	Integrated CLI	Autocomplete Mute (.tabignore)
VS Code	✔ (Roo Code / Cline / Copilot)	✔ (CPH Extension)	✔	✔
Google Antigravity	✔ (Native 1-Command)	✔ (CPH Extension)	✔	✔
Cursor	✔ (Native Composer MCP)	✔ (CPH via Open VSX/Marketplace)	✔	✔
Windsurf	✔ (Native Cascade MCP)	✔ (CPH Extension)	✔	✔
Zed	✔ (Context Servers)	— (Uses CLI harpy test)	✔	✔
Claude Desktop	✔ (Native MCP)	— (Uses CLI harpy test)	✔	✔
Neovim / JetBrains	— (Terminal / LLM plugins)	✔ (Competitive Companion / CLI)	✔	✔

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1. VS Code

CPH Extension Setup

1. Install the Competitive Programming Helper (cph) extension from the VS Code Marketplace: ext install divyanshuaggarwal.competitive-programming-helper
2. When you push a problem using harpy push <slug>, it opens directly in the CPH sidebar with all test cases preloaded.
3. Offline support: Harpy automatically creates .cph/.<slug>.cpp_<hash>.prob files so tests load even without an active network connection.

AI Assistant (Roo Code / Cline / GitHub Copilot Chat)

Add Harpy to your MCP settings file (e.g. cline_mcp_settings.json or .vscode/mcp.json):

{
  "mcpServers": {
    "harpy": {
      "command": "python3",
      "args": ["-m", "harpy.mcp_server"]
    }
  }
}

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2. Google Antigravity IDE

Harpy has first-class native integration with Antigravity:

1. Run the one-command installer:

   harpy setup-ai
   

   This automatically:
   • Registers the MCP server in ~/.gemini/config/mcp_config.json.
   • Installs the multimodal harpy-cp skill globally in ~/.gemini/config/skills/harpy-cp/SKILL.md.
2. Open any folder (harpy init), drop a screenshot of a problem or contest into chat, and say:

   "Set this problem up."

3. Antigravity automatically:
   • Formulates problem.md.
   • Writes <slug>.cpp with typed LeetCode solve(...) signature.
   • Runs the brute-force Python script to verify sample, edge, and stress cases.
   • Syncs with CPH and gives you a clickable file link to your code.

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3. Cursor

1. Open Cursor Settings (Cmd+, or Ctrl+,) → Features → MCP.
2. Click + Add New MCP Server:
   • Name: harpy
   • Type: command
   • Command: python3 -m harpy.mcp_server
3. Alternatively, create a .cursor/mcp.json file in your workspace:

   {
     "mcpServers": {
       "harpy": {
         "command": "python3",
         "args": ["-m", "harpy.mcp_server"]
       }
     }
   }
   

4. Add to your .cursorrules (optional, for optimal prompt alignment):

   When asked to set up a competitive programming or algorithm problem:
   1. Use the `harpy_setup_problem` tool.
   2. Leave the body of `solve(...)` empty for the user with pre-filled typed parameters from `main()`.
   3. Write a brute-force Python script and use `harpy_oracle_generate_tests`.
   4. Sync to CPH using `harpy_sync_cph`.
   

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4. Windsurf (Codeium)

Windsurf supports MCP via Cascade:

1. Open or create ~/.codeium/windsurf/mcp_config.json (or workspace .windsurf/mcp.json):

   {
     "mcpServers": {
       "harpy": {
         "command": "python3",
         "args": ["-m", "harpy.mcp_server"]
       }
     }
   }
   

2. Restart Cascade. Harpy tools will appear with a green indicator in the tools list.

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5. Claude Desktop

In ~/.config/Claude/claude_desktop_config.json (Linux/macOS) or %APPDATA%\Claude\claude_desktop_config.json (Windows):

{
  "mcpServers": {
    "harpy": {
      "command": "python3",
      "args": ["-m", "harpy.mcp_server"]
    }
  }
}

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6. Zed Editor

Zed supports context servers via ~/.config/zed/settings.json:

{
  "context_servers": {
    "harpy": {
      "command": {
        "path": "python3",
        "args": ["-m", "harpy.mcp_server"]
      }
    }
  }
}

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7. Neovim & Terminal-First Workflow

For Neovim, tmux, and terminal-first users:

1. Interactive Testing: Run harpy test <slug> in a side tmux pane, floating terminal, or Neovim terminal (:terminal harpy test <slug>).
2. Watch Mode: Use with entr or nodemon to automatically test whenever you save your solution:

   ls problems/<slug>/*.cpp | entr -c harpy test <slug>
   

3. Tab Completion: Auto-completes subcommands, problem slugs, and solution files:

   harpy test lexi<TAB>
   

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📁 Problem Structure

Harpy automatically organizes problems by algorithmic topic into standard CSES category subfolders:

problems/<category>/<slug>/
├── problem.md         # LeetCode-style specification with LaTeX constraints
├── problem.json       # Structured problem metadata & test cases
├── <slug>.cpp         # Starter template with pre-filled typed solve(...)
├── tests/
│   ├── in_01.txt      # Input for test case 1
│   ├── out_01.txt     # Verified expected output for test case 1
│   └── ...
└── .cph/
    └── .<slug>.cpp_<hash>.prob  # Native CPH offline test file

Supported CSES categories include dynamic-programming, graph-algorithms, tree-algorithms, sorting-and-searching, greedy-algorithms, range-queries, mathematics, string-algorithms, geometry, bit-manipulation, introductory-problems, and advanced-techniques.

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🧪 Development & Testing

Run unit tests:

pytest -v

Build standalone package:

python3 -m build

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📄 License

This project is licensed under the MIT License.