How to Build a Free Local AI Coding Environment with GPT-OSS, Opencode, and Vibe Kanban

Looking to supercharge your development workflow with local, open-source AI tools? Discover how to set up a private, cost-effective AI coding environment using GPT-OSS, Opencode, and Vibe Kanban. This step-by-step guide helps API developers, backend engineers, and technical teams boost productivity, automate tasks, and streamline project management—right from your own machine.

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Why Build a Local AI Coding Stack?

Privacy: Code never leaves your machine
Cost Savings: No cloud AI expenses
Performance: Harness the power of modern AI models locally

Developers often juggle multiple tools for code generation, automation, and project tracking. By integrating GPT-OSS with Opencode and Vibe Kanban, you can streamline your workflow, manage tasks visually, and keep sensitive projects secure—ideal for API design, backend logic, or internal tooling.

Meet the Stack: GPT-OSS, Opencode, and Vibe Kanban

GPT-OSS
A free, open-weight LLM (20B and 120B parameters) designed for reasoning and code generation. Run it locally with Ollama for maximum privacy—no API keys needed.

Opencode
An open-source coding agent by SST, Opencode runs in your terminal. It reads, writes, edits, and manages your codebase using local LLMs like GPT-OSS. Fully provider-agnostic, it supports Language Server Protocols for robust code intelligence.

Vibe Kanban
A modern Kanban-style project management tool that integrates with Opencode and GitHub. Plan features, automate coding tasks, and review code changes—all in one interface.

Together, these tools create a developer-centric environment for project planning, code generation, and seamless collaboration.

Step 1: Install Opencode

Opencode is the backbone of your local AI development environment.

On macOS/Linux

Choose your preferred installation method:

# Quick script
curl -fsSL https://opencode.ai/install | bash

# Or use a package manager
npm i -g opencode-ai@latest     # Node.js
brew install sst/tap/opencode   # macOS/Linux
paru -S opencode-bin            # Arch Linux

On Windows

Download the latest opencode.exe from github.com/sst/opencode/releases.
Save it to a folder, e.g., C:\opencode.
(Optional) Add the folder to your PATH.

Verify Installation

macOS/Linux: Run opencode in your terminal.
Windows: Run C:\opencode\opencode.exe.

You should see Opencode's terminal UI (TUI). If not, check your PATH or binary location.

opencode agent

Step 2: Set Up Your Opencode Project

Let's configure Opencode for a real project: a portfolio website.

1. Create a Project Folder

mkdir opencode-vibekanban-project
cd opencode-vibekanban-project

2. Define Agent Tooling Rules

Create AGENTS.md:

# Tooling rules for Opencode
- Use Opencode tools only: read, write, edit, list, glob, grep, webfetch, bash, task, todowrite, todoread.
- Do NOT call non-existent tools like Repo_browser.*.
- Prefer `edit` for modifying existing files; use `read` to inspect before editing.

3. Configure Opencode

Create opencode.json:

{
  "$schema": "https://opencode.ai/config.json",
  "provider": {
    "ollama": {
      "npm": "@ai-sdk/openai-compatible",
      "name": "Ollama (local)",
      "options": {
        "baseURL": "http://localhost:11434/v1"
      },
      "models": {
        "gpt-oss:20b": { "name": "gpt-oss 20B (local)" }
      }
    }
  },
  "model": "ollama/gpt-oss:20b",
  "agent": {
    "build": {
      "description": "Default coding mode with only Opencode tools.",
      "tools": {
        "read": true,
        "write": true,
        "edit": true,
        "bash": true,
        "grep": true,
        "glob": true,
        "list": true,
        "webfetch": true,
        "patch": true,
        "todoread": true,
        "todowrite": true
      },
      "prompt": "{file:./AGENTS.md}"
    }
  },
  "instructions": ["AGENTS.md"]
}

To use GPT-OSS 120B:
Replace the provider and model sections:

"provider": {
  "ollama": {
    "npm": "@ai-sdk/openai-compatible",
    "name": "Ollama (local)",
    "options": {
      "baseURL": "http://localhost:11434/v1"
    },
    "models": {
      "gpt-oss:120b": { "name": "gpt-oss 120B (local)" }
    }
  }
},
"model": "ollama/gpt-oss:120b"

Step 3: Install and Run GPT-OSS with Ollama

GPT-OSS runs locally using Ollama. You'll need:

16GB+ RAM for 20B
64GB+ RAM for 120B

1. Install Ollama

Download and install from ollama.ai (macOS, Linux, or Windows with WSL2).

2. Pull the GPT-OSS Model

# For 20B (recommended for most)
ollama pull gpt-oss:20b

# For 120B (requires more resources)
ollama pull gpt-oss:120b

gpt-oss model on ollama

3. Start the Model

ollama run gpt-oss:20b
# or
ollama run gpt-oss:120b

Ensure Ollama is running at http://localhost:11434 before starting Opencode.

Step 4: Launch Opencode in Your Project

Start Opencode with your configuration:

cd opencode-vibekanban-project
opencode .
# Or on Windows:
C:\opencode\opencode.exe .

The Opencode TUI should load, showing your project directory and the selected GPT-OSS model.

configure opencode with gpt-oss model

Step 5: Generate a Portfolio Website with Opencode

Let’s build a React-based portfolio landing page for “John Doe” using GPT-OSS.

1. Prompt Opencode

Type the following in the TUI:

Create a simple portfolio landing page for a developer called John Doe in React with Vite.

Opencode will generate required files: index.html, src/App.jsx, vite.config.js, etc.

2. Run the Site

cd john-doe-portfolio
npm install
npm run dev

Visit http://localhost:5173 to preview.

simple portfolio website

3. Push to GitHub

Create a new repo (e.g., john-doe-portfolio).
Initialize and push your code:

git init
git add .
git commit -m "Initial portfolio website"
git remote add origin https://github.com/your-username/john-doe-portfolio.git
git push -u origin main

Tip: Use Opencode’s webfetch tool to pull sample code or inspiration as needed.

Step 6: Integrate Vibe Kanban for Project Management

Power up your workflow with Vibe Kanban to manage tasks and automate enhancements.

1. Install and Launch Vibe Kanban

npx vibe-kanban

Access the web UI at http://localhost:3000.

2. Configure Vibe Kanban

Coding Agent: Select Opencode (auto-detected)
IDE: Choose VS Code, Cursor, or Windsurf
GitHub: Authenticate and link your repositories

link vibe kanban with github

3. Create and Link a Project

Click “Create New Project”
Select your john-doe-portfolio repo
Name your project and continue

create a new project

Step 7: Enhance Your Project with AI-Driven Tasks

Let’s add a new feature—like updating the color scheme.

1. Add a Task

Click “New Task”
Example:
- Title: User Interface Update
- Description: Replace the black colour on the website with dark yellow
Click “Create and Start”

create a task

2. Assign the AI Agent

Choose Opencode as the coding agent
Task moves to “In Progress” and Opencode begins code changes

select opencode as your agent

3. Review and Approve

Task moves to “In Review” once done
Use the diff viewer or open in your IDE
If satisfied, click “Finish” to commit and push:

git add .
git commit -m "Added contact form"
git push

Tip: Queue multiple enhancements (like “Add dark mode,” “Optimize images”) and let Opencode automate them.

Troubleshooting

Opencode TUI not loading? Ensure Ollama is running and opencode.json is valid.
Model slow or crashing? Use the 20B model for lighter machines.
Vibe Kanban GitHub issues? Confirm authentication and repo visibility.
Mock data not working? Review todoread and todowrite logs in Opencode.
Windows binary errors? Re-download from the official releases page.

Why This Workflow Matters for Developers

Local, Secure, and Cost-Effective: No cloud dependency; your code stays private.
Advanced AI Coding: GPT-OSS rivals paid LLMs, with both lightweight and heavy-duty options.
Visual Project Management: Vibe Kanban brings clarity to software tasks and collaboration.
Open Source, Community-Driven: Contribute and shape tools you rely on.

"Opencode with GPT-OSS built my site in minutes, and Vibe Kanban kept everything organized."

For API-driven projects, integrating Apidog into your workflow ensures your documentation and team collaboration stay as streamlined as your code.

Conclusion

With GPT-OSS, Opencode, and Vibe Kanban, you can build a powerful, local AI coding environment—perfect for API development, automation, and project management. Experiment, contribute, and share your creations.

💡 Streamline API development and testing with beautiful API documentation and integrated team workflows using Apidog—replace Postman for less.

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