SpecKit Companioninstall

OPEN SOURCE · RUNS IN YOUR EDITOR

Spec-driven development,
one level up.

Read a run instead of a folder. Keep what you learned instead of archiving it. Send your review notes back to your agent by writing in the margin, not by re-prompting from scratch.

Your specs. Your pipeline. Your record. Your repo.

Install for VS CodeRead the docs

The whole run on one page: what it was for, what it decided, and what traced to a test.

Want to learn spec-driven development, start to finish? soon

A course with Spec Kit: take a vague idea to a spec, a plan, tasks and shipped code.See the outline

You stop reading four markdown files

A finished run becomes one page: what it was for, how it was approached, where in the codebase it landed, and what it decided against — with a coverage table that puts untraced requirements first.

Read the Overview guide
Overview · the run’s story
The Overview's content column: the intent the run answers to, each phase with the time it took, the approach, the corner of the codebase it changed, how it was sized, and the expectations fence.

Every picture is the extension itself. The first four are short clips.

VS CodeGitHub Copilot appClaude Code

Install it where you work

Three steps wherever you are. They all read the same spec files, so you can use more than one.

VS Code

  1. Get Spec Kit

    GitHub’s toolkit for spec-driven development. The stock PyPI `specify-cli` has no `extension` command, so use this build.

    uv tool install specify-cli --from git+https://github.com/github/spec-kit.git --force

  2. Add the Companion extension for Spec Kitoptional

    Recommended. It records each run and adds the Companion pipeline. The same command updates it later.

    specify extension add companion --from https://github.com/alfredoperez/speckit-companion/releases/download/companion-latest/companion.zip --force

  3. Install the VS Code extension

    The workspace: viewer, review, live runs, overview. Then choose your assistant in the picker it shows.

    Open in VS Code
The spec viewer in a VS Code tab: a spec marked Implementing, its documents as tabs, and the Tasks tab at 50% with the first two tasks ticked.
The spec viewer, in a VS Code tab. The full workspace: sidebar, viewer, review, live runs and the Overview.
See the full VS Code path, with what to expect at each step

GitHub Copilot app

  1. Get Spec Kit

    GitHub’s toolkit for spec-driven development. The stock PyPI `specify-cli` has no `extension` command, so use this build. Then set the project up for Copilot, from its root.

    uv tool install specify-cli --from git+https://github.com/github/spec-kit.git --force
    specify init --here --integration copilot

  2. Add the Companion extension for Spec Kitoptional

    Recommended. It records each run and adds the Companion pipeline. The same command updates it later.

    specify extension add companion --from https://github.com/alfredoperez/speckit-companion/releases/download/companion-latest/companion.zip --force

  3. Add the board

    From a checkout of the SpecKit Companion repository. Swap <project> for your project, then commit to your default branch.

    cp -R apps/copilot-canvas/com.github.copilot/extensions/speckit-companion <project>/.github/extensions/speckit-companion

  4. Accept the repository content and start a new session

    Choose Review repository content, then Accept for new sessions. Only a new session gets the board. Then ask for it.

    Open the SpecKit Companion canvas.
The spec board in the GitHub Copilot app: every spec with its status on the left, and the selected spec on the right with its four steps and a Run implement button.
The spec board, beside the chat. Every spec in the repo, and a button that runs the next step.
See the full Copilot app path, with what to expect at each step

Claude Code

  1. Get Spec Kit

    GitHub’s toolkit for spec-driven development. The stock PyPI `specify-cli` has no `extension` command, so use this build. Then set the project up for Claude Code, from its root.

    uv tool install specify-cli --from git+https://github.com/github/spec-kit.git --force
    specify init --here --integration claude

  2. Add the Companion extension for Spec Kitoptional

    Recommended. It records each run and adds the Companion pipeline. The same command updates it later.

    specify extension add companion --from https://github.com/alfredoperez/speckit-companion/releases/download/companion-latest/companion.zip --force

  3. Add the mod

    Needs Claude Code 2.1.287 or later. In a session that is already open, run /reload-plugins, then /speckit-tracker.

    claude plugin marketplace add https://speckit-companion.dev/plugins/marketplace.json
    claude plugin install speckit-companion@speckit-companion
The Companion pane in a Claude Code terminal: the four steps with Implement running, the documents the spec has, and its tasks at 3 of 6.
The tracker pane, beside the transcript. One line above the prompt, and the steps and tasks in your terminal.
See the full Claude Code path, with what to expect at each step

Your pipeline, drawn as a boardbeta

The Workflow Builder shows what your assistant does at each Companion step. Change it on the board, then build. It ships in the VS Code extension today, in beta, and it is still changing.

The Workflow Builder: specify, plan, tasks and implement as four columns, each with its phases and nodes. Two steps are marked changed, and hooks from companion.yml sit before and after the nodes they are attached to.
The Workflow Builder, in a VS Code tab

  • See the run before you start one

    Each step is a column. Inside it are its phases, the nodes your assistant reads, and the files a run writes.

  • Spot what is yours

    Anything your project changed carries one color. A chip in the header says how many steps differ from shipped.

  • Edit, move or replace a node

    Rewrite a node, drag it to reorder, or swap it for an alternative. Your version is saved in your repo and the shipped one is untouched.

  • Attach your own work

    Add a skill, an instruction, a shell command or a node of your own before or after any node. Your assistant reads it at that point.

  • Build when you are ready

    Add a step, or start a workflow from a preset. Nothing takes effect until you press Build, and a failed build changes nothing.

It opens from the circuit icon at the top of the Specs view, and needs the Companion extension for Spec Kit.Read the Workflow Builder guide

Also in the box

The smaller things you get with the VS Code extension.

Watch it run, keep the record

Phases and timing while the agent works, written to one file you can commit.

Track progress

Twelve providers

Terminal CLIs, IDE chat, the Claude Code panel. Not every provider supports every piece.

Compare providers

Steering in view

The standing instruction files your assistant already reads, listed in one view.

Steering

Check the code against the spec

On a finished spec, one button sends Spec Kit’s converge command.

Converge

Tasks to issues

Turn the task list into GitHub issues from the Tasks tab. It asks first.

The tasks step

Answer where you read

A report marks what it still needs to know. Answer on the page.

Fix a bug

60–68% leaner specs

Ceremony sized to the change, not to the template. The Companion pipeline skips the sections a typical change never needs.

Read the methodology

A vague requirement dies here, before it becomes wrong code

Install where you work

jumps to quick start · pick VS Code, the Copilot app or Claude Code