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+---
+name: feature-branch-must-merge-to-track-branch
+title: Feature branches must merge into the project's declared track branch
+category: architecture
+severity: required
+---
+
+# Feature branches must merge into the project's declared track branch
+
+## Rule
+
+When a project declares a track branch in `CLAUDE.md`, all feature branches
+MUST merge into that track branch — not into `main` directly. `main` is
+reserved for releases and hotfixes.
+
+## Track branch declaration
+
+The track branch is declared once in `CLAUDE.md`:
+
+```yaml
+# Declares the integration target for this development sprint/module
+trackBranch: purchase
+```
+
+If no `trackBranch` is declared, `main` is the default and feature branches
+merge there directly.
+
+## Why
+
+In multi-module or multi-sprint projects, a named track branch acts as an
+integration buffer:
+
+| Without track branch | With track branch |
+|---|---|
+| Every feature branch merges to `main` | Features collect on track branch |
+| `main` accumulates partial, in-flight work | `main` stays clean for hotfixes |
+| A hotfix requires reverting or cherry-picking | A hotfix branches from `main` unaffected |
+
+The rule protects the invariant: **`main` is deployable at any moment.**
+
+## Merge requirements
+
+1. Feature branch must compile and pass before merge
+2. Merge uses `--no-ff` to preserve branch history in the log
+3. After merge: BC dev status is set to `Done` (see `[[git-lifecycle-must-sync-bc-status]]`)
+
+## The branching model
+
+```
+main
+ └── <track-branch>          (e.g. "purchase" — lives for one sprint/module)
+       └── feature/<name>    ← development happens here
+       └── feature/<name>
+       └── bugfix/<name>
+ └── hotfix/<name>           ← branches from main, merges back to main
+```
+
+At release: track-branch → main (via PR, after full QA).
+
+## Non-compliant
+
+```bash
+# Merging a feature directly to main when a track branch is declared in CLAUDE.md
+git checkout main
+git merge feature/my-feature   # violates rule
+```
+
+## Compliant
+
+```bash
+# Read track branch from CLAUDE.md → merge there
+git checkout purchase
+git merge --no-ff feature/my-feature
+# Then sync BC: gitHubDevStatus = "Done"
+```
+
+## Scope
+
+Applies to every CURABIS project with a `trackBranch` declaration in `CLAUDE.md`.
+Projects without a declaration use `main` as the track branch — no change needed.