feat(init)!: make git extension opt-in and remove --no-git at v0.10.0

docs/installation.md

@@ -6,7 +6,7 @@
 - AI coding agent: [Claude Code](https://www.anthropic.com/claude-code), [GitHub Copilot](https://code.visualstudio.com/), [Codebuddy CLI](https://www.codebuddy.ai/cli), [Gemini CLI](https://github.com/google-gemini/gemini-cli), or [Pi Coding Agent](https://pi.dev)
 - [uv](https://docs.astral.sh/uv/) for package management (recommended) or [pipx](https://pipx.pypa.io/) for persistent installation
 - [Python 3.11+](https://www.python.org/downloads/)
-- [Git](https://git-scm.com/downloads)
+- [Git](https://git-scm.com/downloads) _(optional — required only when the git extension is enabled)_
 
 ## Installation
 

docs/local-development.md

@@ -162,7 +162,7 @@ rm -rf .venv dist build *.egg-info
 |---------|-----|
 | `ModuleNotFoundError: typer` | Run `uv pip install -e .` |
 | Scripts not executable (Linux) | Re-run init or `chmod +x scripts/*.sh` |
-| Git step skipped | You passed `--no-git` or Git not installed |
+| Git step skipped | Git not installed on your system |
 | Wrong script type downloaded | Pass `--script sh` or `--script ps` explicitly |
 | TLS errors on corporate network | Configure your environment's certificate store or proxy. The `--skip-tls` flag is deprecated and has no effect. |
 

docs/reference/core.md

@@ -15,16 +15,13 @@ specify init [<project_name>]
 | `--script sh\|ps`        | Script type: `sh` (bash/zsh) or `ps` (PowerShell)                       |
 | `--here`                 | Initialize in the current directory instead of creating a new one        |
 | `--force`                | Force merge/overwrite when initializing in an existing directory         |
-| `--no-git`               | Skip git repository initialization                                       |
 | `--ignore-agent-tools`   | Skip checks for AI coding agent CLI tools                                |
 | `--preset <id>`          | Install a preset during initialization                                   |
-| `--branch-numbering`     | Branch numbering strategy: `sequential` (default) or `timestamp`         |
 
 Creates a new Spec Kit project with the necessary directory structure, templates, scripts, and AI coding agent integration files.
 
 > [!NOTE]
-> The git extension is currently enabled by default during `specify init`.
-> Starting in `v0.10.0`, it will require explicit opt-in. To add it after init, run `specify extension add git`.
+> Git repository initialization and branching are managed by the **git extension**, which is not installed by default. Run `specify extension add git` after init to enable git workflows.
 
 Use `<project_name>` to create a new directory, or `--here` (or `.`) to initialize in the current directory. If the directory already has files, use `--force` to merge without confirmation.
 
@@ -45,14 +42,8 @@ specify init --here --force --integration copilot
 # Use PowerShell scripts (Windows/cross-platform)
 specify init my-project --integration copilot --script ps
 
-# Skip git initialization
-specify init my-project --integration copilot --no-git
-
 # Install a preset during initialization
 specify init my-project --integration copilot --preset compliance
-
-# Use timestamp-based branch numbering (useful for distributed teams)
-specify init my-project --integration copilot --branch-numbering timestamp
 ```
 
 ### Environment Variables
@@ -67,7 +58,7 @@ specify init my-project --integration copilot --branch-numbering timestamp
 specify check
 ```
 
-Checks that required tools are available on your system: `git` and any CLI-based AI coding agents. IDE-based agents are skipped since they don't require a CLI tool.
+Checks that CLI-based AI coding agents are available on your system. IDE-based agents are skipped since they don't require a CLI tool.
 
 This command stays offline. If a command behaves like an older Spec Kit version or an expected CLI feature is missing, run `specify self check` to check whether your local CLI is behind the latest release.
 

docs/upgrade.md

@@ -257,58 +257,28 @@ rm speckit.old-command-name.md
 # Restart your IDE
 ```
 
-### Scenario 4: "I'm working on a project without Git"
+### Scenario 4: "I don't want the git extension"
 
-If you initialized your project with `--no-git`, you can still upgrade:
+The git extension is now opt-in, so upgrades do not install it unless you add it explicitly.
 
 ```bash
 # Manually back up files you customized
-cp .specify/memory/constitution.md /tmp/constitution-backup.md
+cp .specify/memory/constitution.md .specify/memory/constitution.backup.md
 
 # Run upgrade
-specify init --here --force --integration copilot --no-git
+specify init --here --force --integration copilot
 
 # Restore customizations
-mv /tmp/constitution-backup.md .specify/memory/constitution.md
-```
-
-The `--no-git` flag skips git initialization but doesn't affect file updates.
-
----
-
-## Using `--no-git` Flag
-
-The `--no-git` flag tells Spec Kit to **skip git repository initialization**. This is useful when:
-
-- You manage version control differently (Mercurial, SVN, etc.)
-- Your project is part of a larger monorepo with existing git setup
-- You're experimenting and don't want version control yet
-
-**During initial setup:**
-
-```bash
-specify init my-project --integration copilot --no-git
+mv .specify/memory/constitution.backup.md .specify/memory/constitution.md
 ```
 
-**During upgrade:**
+If you later decide you want the git extension's commands and hooks, install it explicitly:
 
 ```bash
-specify init --here --force --integration copilot --no-git
+specify extension add git
 ```
 
-### What `--no-git` does NOT do
-
-❌ Does NOT prevent file updates
-❌ Does NOT skip slash command installation
-❌ Does NOT affect template merging
-
-It **only** skips running `git init` and creating the initial commit.
-
-### Working without Git
-
-If you use `--no-git`, you'll need to manage feature directories manually:
-
-**Set the `SPECIFY_FEATURE` environment variable** before using planning commands:
+Projects that do not use Git can still work with Spec Kit by setting `SPECIFY_FEATURE` manually before planning commands:
 
 ```bash
 # Bash/Zsh
@@ -318,10 +288,6 @@ export SPECIFY_FEATURE="001-my-feature"
 $env:SPECIFY_FEATURE = "001-my-feature"
 ```
 
-This tells Spec Kit which feature directory to use when creating specs, plans, and tasks.
-
-**Why this matters:** Without git, Spec Kit can't detect your current branch name to determine the active feature. The environment variable provides that context manually.
-
 ---
 
 ## Troubleshooting

extensions/git/commands/speckit.git.feature.md

@@ -31,8 +31,9 @@ If the user explicitly provided `GIT_BRANCH_NAME` (e.g., via environment variabl
 Determine the branch numbering strategy by checking configuration in this order:
 
 1. Check `.specify/extensions/git/git-config.yml` for `branch_numbering` value
-2. Check `.specify/init-options.json` for `branch_numbering` value (backward compatibility)
-3. Default to `sequential` if neither exists
+2. Check `.specify/init-options.json` for `feature_numbering` value (inherit from core)
+3. Check `.specify/init-options.json` for `branch_numbering` value (deprecated, backward compatibility — will be removed in a future release)
+4. Default to `sequential` if none of the above exist
 
 ## Execution
 

scripts/bash/check-prerequisites.sh

@@ -111,9 +111,6 @@ if $PATHS_ONLY; then
     exit 0
 fi
 
-# Validate branch name
-check_feature_branch "$CURRENT_BRANCH" "$HAS_GIT" || exit 1
-
 # Validate required directories and files
 if [[ ! -d "$FEATURE_DIR" ]]; then
     echo "ERROR: Feature directory not found: $FEATURE_DIR" >&2