Spec Loop — Design-First AI-Assisted Development

There are two common ways people use AI for coding.

Vibecoding: you describe intent, the model fills in the gaps, and you get a large diff with undocumented decisions. Review becomes archaeology. Tests are optional by accident.

Waterfall: you try to avoid that by writing a complete spec first. You can’t. Constraints appear during implementation. The spec inflates, then it either blocks change or gets ignored.

Spec Loop avoids both: write the next small spec, review it, then implement it with tests. Keep the spec local to the next step. Repeat until done.

Spec Loop is a framework of reusable skills.

Getting Started

Install the skills with npx skills

Recommended path:

Install the core task-workflow skills together.

Ensure Node.js is available so npx works.

Install Spec Loop in the current project with:

npx skills add dpolivaev/spec-loop -s '*'

Variations:

• -s '*' installs all shipped skills.
• Remove -s '*' to select skills interactively instead of installing the full bundle. That lets you skip the optional spec-loop-setup-doc-rendering and spec-loop-assess-pull-request skills, and skip spec-loop-write-glossary when your project will not use a project glossary.
• Add -g for a global install.
• Use -g --all for a global, non-interactive install for all supported agents.

For selective, single-agent, or other installation variants, see https://github.com/vercel-labs/skills.

Prepare task and glossary rendering

Spec Loop task files use embedded PlantUML diagrams and may also include Mermaid visual glossaries. Spec Loop project glossaries may include Mermaid diagrams. Prepare your editor for reviewing rendered task files and glossary files before continuing.

Ask the agent to use the spec-loop-setup-doc-rendering skill to prepare your editor preview setup.

If you do not want to use the skill and prefer manual setup, use these editor-specific references: VS Code-Based IDE Setup and JetBrains Setup Reference.

For example:

Please use the `spec-loop-setup-doc-rendering` skill to help me
prepare my editor for reviewing rendered Spec Loop task files and
glossary files.

My coding harness may run in a terminal, but I review files in
<VS Code, Cursor, another VS Code-based IDE, or JetBrains>.

When an end-to-end rendering check is useful, the skill should also suggest small Markdown and AsciiDoc probe files that exercise the relevant diagram types, including a class diagram.

If you review files in VS Code, Cursor, or another VS Code-based IDE, the same extension IDs and settings apply. When your editor exposes a supported CLI command, you can also run the helper script directly instead of asking an agent to use the skill. You can either run it from a local checkout or download the current main-branch copy directly from setup-vscode-server-based.sh. The script requires a supported editor CLI command on PATH (code, code-insiders, cursor, code.cmd, code-insiders.cmd, or cursor.cmd) and is intended for macOS, Linux, WSL, and Git Bash for Windows. Other VS Code-based IDEs should apply the same extension IDs and settings manually.

The helper automates only the server-based PlantUML preview path for supported VS Code-based IDEs together with the AsciiDoc extension used by Spec Loop glossaries. It does not automate the local-only PlantUML path or JetBrains setup.

From a local checkout:

bash skills/spec-loop-setup-doc-rendering/scripts/setup-vscode-server-based.sh --check
bash skills/spec-loop-setup-doc-rendering/scripts/setup-vscode-server-based.sh --apply

Without a local checkout:

curl -fsSLO https://raw.githubusercontent.com/dpolivaev/spec-loop/refs/heads/main/skills/spec-loop-setup-doc-rendering/scripts/setup-vscode-server-based.sh
bash setup-vscode-server-based.sh --check
bash setup-vscode-server-based.sh --apply

How to update

Project-level update:

npx skills update

Global update:

npx skills update -g

Manual fallback when npx is unavailable

If npx is not available, clone or download this repository and copy the core task-workflow skills from skills/ into your agent's skills directory. Keep that core bundle together.

Install spec-loop-write-glossary when your project uses a project glossary.

Install spec-loop-setup-doc-rendering only if you want rendering setup or troubleshooting help.

Install spec-loop-assess-pull-request only if you need retrospective review of trusted repositories.

Which directory your agent uses is agent-specific. See https://github.com/vercel-labs/skills for agent-specific installation details.

Further Reading

• How Spec Loop Works — why the workflow scales to large codebases.
• Skills Overview — the skill catalog, reading path, and reference links.
• Diagram and Rendering Policy — PlantUML default, Mermaid fallback, and rendering guidance.
• Governance, Review, and Traceability — approval boundaries, review discipline, and traceability rules.
• AI Workflow Framework Comparison — workflow trade-offs compared with other frameworks.
• Tutorials:
  • Wordle Tutorial
  • Online Art Game Tutorial

License

Licensed under the MIT License. See LICENSE.

Origin

This framework was developed and applied in Freeplane.