Stop prompting AI coding agents like it's 2024

Your coding agents are capable of so much more—they just need an operating system. Introducing, Agent OS.

Your system for spec-driven agentic development.

Agent OS transforms AI coding agents from confused interns into productive developers. With structured workflows that capture your standards, your stack, and the unique details of your codebase, Agent OS gives your agents the specs they need to ship quality code on the first try—not the fifth.

Use it with:

Claude Code, Cursor, or any other AI coding tool.
New products or established codebases.
Big features, small fixes, or anything in between.
Any language or framework.

Why use Agent OS?

Stop wrestling with AI that writes the wrong code. Agent OS transforms coding agents from confused assistants into trusted developers who truly understand your codebase.

3 reasons why product teams use Agent OS:

1
Complete context, not just prompts

Unlike basic AI setups, Agent OS provides three layers of context that work together:

  • Standards - Your coding style, tech stack, and best practices
  • Product - Your mission, architecture, roadmap, and decisions
  • Specs - Detailed plans & tasks for each feature implementation

The result: Agents write code that looks like you wrote it—first time, every time.

2
Structured development, not chaos

Agent OS replaces random prompting and circular rewrites with a proven workflow. It automatically:

  • Writes comprehensive specs before coding begins
  • Breaks features into trackable, TDD-focused tasks
  • Documents key decisions as they happen
  • Updates your roadmap as features ship

The difference: Ship features faster with clear specs and completed tasks—not endless cycles of (re)explaining requirements and redoing work.

3
Your standards, your way

Agent OS is completely yours to shape. Define your own coding standards, write custom instructions, and adapt every workflow to match how your team operates. No rigid interfaces or prescribed processes—just markdown files you control. Works seamlessly with any AI tool or IDE you choose.

The relief: Your coding agent finally feels like a senior developer on your team—thinking your way, following your patterns, and shipping at your standards.

The Three Layers of Context

Agent OS works by layering context—just like you'd onboard a human developer. Each layer builds on the previous one, creating a complete picture of how you build software.

Agent OS - 3 layers of context

Layer 1
Your standards

Your standards define how you build software. Your stack. Your opinions. Your style. Your priorities. The standards you expect everyone on your team to follow when building anything. These should include:

  • Tech Stack — Your default frameworks, libraries, and tools
  • Code Style — Your formatting rules, naming conventions, and preferences
  • Best Practices — Your development philosophy (e.g., TDD, commit patterns, etc.)

Your standards documentation lives on your system in ~/.agent-os/standards/... and are referenced from every project, every codebase. Set once, use everywhere, override as needed.

Layer 2
Your product

At the product (codebase) layer, we document what it is we're building, why we're building it, who it's for, and the big-picture product roadmap. This includes:

  • Mission — What you're building, for whom, and why it matters
  • Roadmap — Features shipped, in progress, and planned
  • Decisions — Key architectural and technical choices (with rationale)
  • Product-specific stack — The exact versions and configurations for this codebase

Product documentation lives in your codebase (.agent-os/product/) and give agents the full picture of your product.

Layer 3
Your specs

Throughout your product's development, you'll create many specs. Each spec is a single feature or enhancement or fix, which typically represents a few hours or days of work (accellerated with the help of AI). Each spec will have its own requirements, technical specs, and tasks breakdown.

Individual feature specifications include:

  • SRD (Spec Requirements Document) — Goals for the feature, user stories, success criteria
  • Technical Specs — API design, database changes, UI requirements
  • Tasks Breakdown — Trackable step-by-step implementation plan with dependencies

Specs live in dated folders inside your codebase (.agent-os/projects/2025-12-19-user-auth/) and guide agents through each spec's implementations.

With all three layers in place, your agent has everything it needs: how you build (Standards), what you're building (Product), and what to build next (Specs). No more confusion, no more rewrites—just clean, consistent code that looks like you wrote it.

Install Agent OS

Getting started with Agent OS is a two-step process:

  1. Base Installation
    Install Agent OS on your system
  2. Tool-Specific Setup
    Set up Claude Code, Cursor, or whichever IDE you're using

Installing Agent OS in an existing codebase that's been around a while? Then see Working with Existing Codebases.

See What Gets Installed Where? to understand where all the Agent OS files will live after installation.


1
Base Installation

Everyone starts here. The fastest way to get started is by running the install script with this one-liner in your terminal:

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curl -sSL https://raw.githubusercontent.com/buildermethods/agent-os/main/setup.sh | bash
What the install script does...
Prefer manual installation?
Follow these instructions instead...

Customize your standards files

Once you've installed the base files, you'll need to customize the standards files in ~/.agent-os/standards/ to match your preferences. This is where you define your way of building software.


2
Tool-Specific Setup

With the base installation complete, now set up Agent OS for your AI tool:

Claude Code Setup

Use the the following one-liner to run the Claude Code setup script:

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curl -sSL https://raw.githubusercontent.com/buildermethods/agent-os/main/setup-claude-code.sh | bash
What the Claude Code setup script does...
Prefer manual installation?
Follow these instructions instead...

That's it! You can now use these commands in Claude Code:

  • /plan-product
  • /create-spec
  • /execute-tasks
  • /analyze-product

Cursor Setup

Using Cursor? For each project where you want to use Agent OS, use the following one-liner to run the Cursor setup script:

Important: First be sure that you're inside your project's root folder so that Cursor rules are installed inside of it.

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curl -sSL https://raw.githubusercontent.com/buildermethods/agent-os/main/setup-cursor.sh | bash
What the Cursor setup script does...
Prefer manual installation?
Follow these instructions instead...

That's it! You can now use these commands in Cursor:

  • @plan-product
  • @create-spec
  • @execute-tasks
  • @analyze-product

Hybrid Setup (Claude Code + Cursor)

Using both Claude Code and Cursor? Follow both setups above to enable Agent OS in both tools.

  1. Follow the Claude Code setup to enable global commands
  2. For each project, follow the Cursor setup to add project rules

Both tools will now work with the same Agent OS installation.

Other AI coding tools...

Agent OS is just markdown files. To adapt it for any AI tool, find where your tool looks for commands or context, then copy our command files there.

  1. Find where your tool looks for commands or context
  2. Copy our command files there, adjusting the format as needed

The command files simply point to the instructions and standards located in your ~/.agent-os/ installation.


Working with Existing Codebases

Already have a product in development? Agent OS works great with existing code:

Complete steps 1 and 2 above for your tool.

Run the @analyze-product command:

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@analyze-product

I want to install Agent OS in my existing codebase

This will analyze your codebase, understand what's already built, and create Agent OS documentation that reflects your actual implementation.


What Gets Installed Where?

After installation, you'll have:

Base Installation:

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~/.agent-os/
├── standards/
│   ├── tech-stack.md         # Your default tech choices
│   ├── code-style.md         # Your formatting preferences
│   └── best-practices.md     # Your development philosophy
└── instructions/
    ├── plan-product.md       # Agent's instructions to initialize a product
    ├── create-spec.md        # Agent's instructions to plan features
    ├── execute-tasks.md      # Agent's instructions to build and ship
    └── analyze-product.md    # Agent's instructions to add to existing code

Claude Code Addition:

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~/.claude/
├── CLAUDE.md                # Points to your default preferences
└── commands/
    ├── plan-product.md      # → points to ~/.agent-os/instructions/
    ├── create-spec.md       # → points to ~/.agent-os/instructions/
    ├── execute-tasks.md     # → points to ~/.agent-os/instructions/
    └── analyze-product.md   # → points to ~/.agent-os/instructions/

your-product/
├── .claude/
│   └── CLAUDE.md          # Points to project details and instructions
└── .agent-os/
    ├── product/           # Created by plan-product
    └── specs/             # Created by create-spec

Cursor Addition (Per Project):

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your-product/
├── .cursor/
│   └── rules/
│       ├── plan-product.mdc       # → points to ~/.agent-os/instructions/
│       ├── create-spec.mdc        # → points to ~/.agent-os/instructions/
│       ├── execute-tasks.mdc      # → points to ~/.agent-os/instructions/
│       └── analyze-product.mdc    # → points to ~/.agent-os/instructions/
├── .agent-os/
│   ├── product/                   # Created by plan-product
│   └── specs/                     # Created by create-spec
└──CLAUDE.md                       # If also using Claude Code

Using Agent OS

With Agent OS installed, you're ready to supercharge your AI coding workflow. Here's how to use each part:


Setting Your Standards

Before starting any project, customize your global standards to match how you like to build. Your agent will reference these standards constantly when planning projects and writing code, so make them reflect your actual preferences:

Edit your tech stack
~/.agent-os/standards/tech-stack.md
Edit your code style
~/.agent-os/standards/code-style.md
Edit your best practices
~/.agent-os/standards/best-practices.md

💡 Pro tip: Be opinionated! The more specific your standards, the more consistent your agent's output.


Starting a New Product

When beginning a fresh codebase, you can provide as much or as little detail as you want—though more detail leads to better results by using the @plan-product command.

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@plan-product

I want to build a SaaS tool for tracking customer feedback
Key features: feedback collection, sentiment analysis, reporting dashboard
Target users: Product managers at B2B SaaS companies
Tech stack: Use my defaults

Note: When starting a new product, feel free to provide as much or as little detail in your initial prompt. You can even invoke the @plan-product command with no other details and your agent will then prompt you for the specific details it needs to get started on your product's plan and roadmap.

Once your agent has collected the basic details it needs, it will:

  • ✅ Create .agent-os/product/ structure
  • ✅ Generate mission.md with product vision
  • ✅ Create a 5-phase roadmap
  • ✅ Document all technical decisions
  • ✅ Set up your preferred tech stack

Important: Review and edit the generated documentation to ensure it accurately reflects your vision and goals.


Adding Agent OS to Existing Products

Have an existing codebase? No problem. Use the @analyze-product command to install Agent OS into your existing codebase.

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@analyze-product

I want to install Agent OS in my existing codebase

Your agent will:

  • 🔍 Analyze your current code structure
  • 📊 Detect your tech stack and patterns
  • 📝 Create documentation reflecting what's already built
  • ✅ Add completed features to "Phase 0" in the roadmap

Important: Review the generated documentation carefully—your agent's analysis might miss nuances or business context that only you know.


Planning a Feature

Ready to build something new? You have two options:

Option 1: Ask "what's next?"

Your agent should automatically trigger the @create-spec command, check your product's roadmap.md file, and suggest the next uncompleted feature. You can confirm or adjust the feature before proceeding.

Option 2: Request a specific feature

Use the @create-spec command along with your instructions or request for a new feature or task.

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@create-spec

Let's add user authentication with email/password and OAuth

Either way, your agent will:

  • 📋 Create a Spec Requirements Document (SRD)
  • 🔧 Write technical specifications
  • 💾 Design database schemas (if needed)
  • 🔌 Document API endpoints (if needed)
  • ✅ Break down work into ordered tasks

Important: This is the most critical review point! Carefully examine the SRD, specs, and especially the task breakdown. Adjust anything that doesn't match your expectations before proceeding.

Specs live in: .agent-os/specs/2025-07-16-user-authentication/


Executing Tasks

Time to code! Start building:

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@execute-task

Work on the next task in the user authentication project

By default, your agent will complete one parent task and all its sub-tasks. You can adjust this:

  • More work: "Complete tasks 1 and 2 with all sub-tasks"
  • Less work: "Just do task 1.1 and 1.2"
  • Specific task: "Work on task 3: API endpoints"

Your agent will:

  • 📝 Follow your coding standards exactly
  • 🧪 Write tests first (if that's your style)
  • 💾 Commit with clear messages
  • ✅ Update task progress as it goes
  • 🔊 Play a sound when done

Important: While agents are great at following patterns, always review the code for business logic accuracy and edge cases before merging.


Workflow Examples

Example 1: Monday Morning

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What's next on the roadmap?

Your agent checks .agent-os/product/roadmap.md and suggests the next uncompleted feature.

Example 2: Quick Bug Fix

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@create-spec

Users report the dashboard is slow when filtering by date

Even for bug fixes, your agent creates a mini-spec with clear tasks.

Example 3: Continuing Work

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@execute-task

Continue where we left off yesterday

Your agent reads the task list and picks up exactly where it stopped.

Refining Your Agent OS

Agent OS gets better with use. Each spec teaches you something about your process, your preferences, and how to better guide your AI agents. Here's how to continuously improve your setup.


The Refinement Loop

After each feature or spec, ask yourself:

  1. What worked well?
    Patterns to document and repeat
  2. What needed correction?
    Gaps in your standards or instructions
  3. What surprised you?
    Unexpected approaches that might be worth adopting

Common Refinements

After Your First Project

  • Add specific examples to code-style.md based on actual code
  • Update best-practices.md with patterns you had to correct
  • Clarify any tech stack choices that caused confusion

After Code Reviews

  • Notice yourself making the same corrections? Add them to standards
  • Find a pattern you love? Document it so agents use it consistently
  • Spot anti-patterns? Add them to best-practices.md with clear "don't do this" examples

After Team Feedback

  • Incorporate team preferences into your standards
  • Add team-specific workflows to best-practices.md
  • Document naming conventions everyone agrees on

Where to Make Updates

Standards Files (Global - affects all specs)

  • tech-stack.md - New tool preferences, version updates
  • code-style.md - Formatting patterns, naming conventions
  • best-practices.md - Development philosophy, patterns to follow/avoid

Product Files (Product-specific)

  • roadmap.md - Adjust phases based on learnings
  • decisions.md - Document why certain approaches work (or don't)
  • tech-stack.md - Override global standards when needed

Making Refinements Stick

Be Specific

  • ❌ "Write better tests"
  • ✅ "Write integration tests first, then unit tests. Mock external services using [specific pattern]"

Show, Don't Just Tell

  • Include code examples in your standards
  • Show both good and bad patterns
  • Explain why one approach is preferred

Version Your Changes

  • Update version numbers when making significant changes
  • Keep a brief changelog at the bottom of modified files
  • This helps track what changed and when

Team Refinement

If working with a team:

  1. Schedule Regular Reviews
    Monthly or after major features
  2. Collect Patterns
    What is everyone correcting in code reviews?
  3. Reach Consensus
    Agree on patterns before adding to standards
  4. Share Updates
    Ensure everyone updates their local Agent OS files

Signs You Need Refinement

  • You're making the same corrections repeatedly
  • Agents consistently miss certain patterns
  • Code reviews reveal style inconsistencies
  • New team members point out unclear conventions
  • You discover better patterns worth standardizing

The Long Game

Remember: Agent OS is a living system. The goal isn't perfection on day one—it's continuous improvement. Each refinement makes your agents more effective and your codebase more consistent.

Your Agent OS a year from now will be dramatically better than today's, shaped by real experience and tailored to exactly how you and your team work best.

Best Practices

While Agent OS's task execution process automatically updates your roadmap and prompts for decision updates, it's good practice to regularly:

  1. Review and refine your standards
    As you see patterns in code reviews, update your standards files
  2. Regularly review roadmap.md
    Ensure it reflects actual progress and priorities
  3. Update decisions.md
    Document important choices that affect future development
  4. Refine best-practices.md
    Add patterns that help your agent think like you think

Regular maintenance keeps your Agent OS aligned with your evolving project and team needs.


Tips for Success

Review Plans Carefully

  • The planning phase is crucial—invest time here to save time later
  • Review the PRD and task breakdown before execution
  • Ask your agent to adjust plans if something doesn't look right
  • Ensure you're aligned on the approach before coding begins

Start Small

  • Don't try to document everything at once
  • Begin with basic standards, refine as you go

Be Specific

  • "Use PostgreSQL" → "Use PostgreSQL 15+ with schemas for multi-tenancy"
  • "Write tests" → "Write unit tests first, aim for 80% coverage"

Trust the Process

  • Let your agent own entire features, not just snippets
  • Review and refine rather than micromanage

Know When to Start Fresh

  • Not happy with the implementation? It's often better to revert and redo with better planning
  • Don't ask your agent to fix incorrectly implemented code—start clean with refined specs
  • A clear redo usually beats incremental fixes

Troubleshooting

Agent not following your style?

  • Check your standards files are specific enough
  • Add examples to code-style.md
  • Update best-practices.md with clear dos and don'ts

Tasks too big or too small?

  • This is a planning issue—catch it early!
  • During create-spec, review the task breakdown carefully
  • Ask your agent to adjust: "Can you break task 3 into smaller sub-tasks?"
  • Or: "Tasks 2 and 3 should be combined"

Wrong technical approach?

  • Review technical specs during the planning phase
  • Don't wait until code is written to course-correct
  • Say: "I'd prefer we use [different approach] for this"
  • Update tech-stack.md, decisions.md, or best-practices.md to prevent future issues
  • Best-practices.md is especially important—it teaches your agent to think like you

Remember: The best time to fix issues is during planning, not after code is written!

FAQ

What is Agent OS?
What makes Agent OS different?
What is 'spec-driven development'?
Is Agent OS free?
Who created Agent OS?
What's Builder Methods?
I don't use Claude Code or Cursor. Can I still use Agent OS?
Is support or coaching available for me or my team?
How can I learn more about building with AI?
I have more questions!
Builder Methods

Training for pro software developers building with AI.

Created by Brian Casel (that's me). I'm a career software developer, founder, and creator of Builder Methods and the Agent OS system for building with AI.

© 2025 CasJam Media, LLC / Builder Methods
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