dev-loop

Automated development loop powered by GitHub Copilot CLI. Each phase shells out to copilot -p "..." --yolo with a crafted prompt. Specs follow the spec-kit convention — numbered Markdown files (NN-slug.md) with a CONSTITUTION.md defining product constraints. Each spec is processed one at a time — plan, build, review — all phases to completion before moving to the next.

Requirements

• GitHub Copilot CLI (copilot on $env:PATH)
• PowerShell 7+
• Git
• The target project directory must be a git repository (git init)

Install

From PowerShell Gallery

Install-Module -Name dev-loop

From Source

git clone https://github.com/markgar/dev-loop.git

Usage

As a module (installed from Gallery)

Invoke-DevLoop -SpecsDir '<path>' -ProjectDir '<path>' [-GitPush] [-Model <model>]

As a script (cloned from repo)

.\dev-loop.ps1 -SpecsDir '<path>' -ProjectDir '<path>' [-GitPush] [-Model <model>]

Choosing a Model

By default, Copilot CLI picks its own model. Use -Model to override:

Invoke-DevLoop -SpecsDir ./specs -ProjectDir . -Model claude-sonnet-4

Run copilot --help to see available models.

Quick Start with Sample Specs

The repo includes sample specs in spec-kit style — a CONSTITUTION.md and two numbered specs that describe a bookstore REST API:

• CONSTITUTION.md — Product constraints (tech stack, conventions, principles)
• 01-bookstore-rest-api.md — Core CRUD endpoints for a bookstore API
• 02-book-search-filtering.md — Search and filtering capabilities

mkdir ~/my-bookstore
cd ~/my-bookstore
git init

# Point dev-loop at the sample specs
'<path-to-dev-loop>/dev-loop.ps1' -SpecsDir '<path-to-dev-loop>/sample-spec' -ProjectDir .

The dev-loop will plan, build, and review each spec in order — generating the entire project from scratch in your target directory.

How It Works

Invoke-DevLoop -SpecsDir '<path>' -ProjectDir '<path>' [-GitPush]
    │
    ├── preflight.ps1  — Discover specs, constitution review
    │
    └── Per-spec loop:
        ├── plan.ps1       — Decompose spec into commit-sized tasks
        ├── plan-eval.ps1  — Review & fix the plan in-place
        ├── build.ps1      — Build next unchecked task (loops until plan complete)
        └── review.ps1     — Senior SWE code review + standards capture

The Phases

Phase	Agent	What it does
Preflight	preflight.ps1	Scans the specs directory, discovers numbered spec files, and reviews CONSTITUTION.md for anything that would interfere with the dev-loop process. Runs once per invocation.
Plan	plan.ps1	Reads a single spec and the constitution, then produces a checklist of commit-sized tasks in plan-<spec>.md. Each task = one git commit.
Plan Eval	plan-eval.ps1	Reviews the generated plan against the spec for completeness, ordering, coherence, and scope. Fixes the plan file in-place if anything is off.
Build	build.ps1	Picks up the next unchecked task from the plan, implements it, runs existing tests, checks it off, and commits. Loops until all tasks are checked.
Review	review.ps1	Acts as a senior SWE reviewer — fixes code quality issues, updates ENGINEERING_STANDARDS.md with reusable learnings, keeps copilot-instructions.md in sync, and ensures minimal documentation (README, CHANGELOG) exists.

A CONSTITUTION.md at the specs root defines product constraints included in every prompt.

Tracking

Each run creates a timestamped directory under .dev-loop/ in the target project:

.dev-loop/
└── 20260304-183305/
    ├── dev-loop.log              # Orchestrator summary
    ├── preflight.log             # Spec discovery + constitution check
    ├── 01-my-feature.log         # All phases for this spec
    ├── manifest.json             # Per-spec phase timestamps
    ├── spec-discovery.json       # Discovered specs
    ├── plan-01-my-feature.md     # Task checklist for spec 01
    └── preflight-findings.md     # (only if constitution has issues)

Phase timestamps in manifest.json enable checkpoint/resume — completed phases are skipped on re-run.

Inspecting a Run with GitHub Copilot

While dev-loop is running (or after it finishes), open the target project directory in VS Code:

code ~/my-bookstore

The .dev-loop/ tracking directory contains logs, plans, and manifests that GitHub Copilot can read. Open Copilot Chat and ask things like:

• "What phase of the dev-loop build are we in right now?"
• "Summarize what happened in spec 01."
• "Are there any failures in the latest run?"

Because everything is plain text, Copilot has full context to answer questions about the current state of the build.

Project Structure

dev-loop/
  dev-loop.ps1              # Thin launcher (clone-and-run convenience)
  README.md
  sample-spec/              # Sample specs (not published to Gallery)
  src/
    dev-loop/               # PowerShell module (published to Gallery)
      dev-loop.psd1         # Module manifest
      dev-loop.psm1         # Module implementation (Invoke-DevLoop)
      agents/               # Phase scripts

Contributing

Contributions are welcome! Please open an issue to discuss a change before submitting a pull request.

License

This project is licensed under the MIT License.