Spec docs drift from code, or they bloat every PR. Skeeper picks neither.

It mirrors SPEC.md, ADRs, RFCs, and AI plan files into a sidecar Git repository and commits a tiny skeeper.lock to your main repo that pins every commit to exact sidecar commits. PR diffs stay focused on code, spec history stays auditable, and nothing silently drifts because the managed Git hooks fail the commit if the sidecar state cannot be proven.

✨ Highlights

• Lockfile-backed reliability. skeeper.lock records sidecar URL, source branch, namespace branch, sidecar commit, per-namespace digest, file count, and byte count.
• Strict managed hooks. The managed pre-commit and pre-merge-commit hooks sync staged content, push the sidecar, write and stage skeeper.lock, and fail closed. The managed pre-push hook verifies the lock against the sidecar remote.
• Specs stay local to their code. Edit SPEC.md, docs/specs/**, .claude/plans/**, ADRs, RFCs, or custom globs where they naturally belong.
• Shared sidecars without collisions. Namespaces isolate stored paths and sidecar branches inside one sidecar remote.
• Branch-aware history. Namespace branches use <namespace>/__branches__/<source-branch>.
• Fresh-clone hydration. skeeper hydrate restores files from the locked sidecar commits, not a best-effort latest branch.
• Agent-friendly commands. status, sync, verify, fsck, hooks check, repair status, pattern, adopt, and untrack all support deterministic output where needed.
• Skill for AI agents. A bundled skill at .agents/skills/skeeper/SKILL.md teaches coding agents the strict-sync workflow, namespaces, and recovery commands.

🎯 Who Is This For

• Teams using AI coding agents that produce SPEC.md, PRD, TechSpec, and plan markdown next to code.
• Engineering organizations running ADRs, RFCs, and design docs in-repo without making every PR a docs+code review.
• Solo developers who want full spec history (git log, git blame, branches, PRs) without polluting their main repository's diff.

📦 Installation

go install github.com/compozy/skeeper/cmd/skeeper@latest

Other release channels are available through GitHub Releases, Homebrew, NPM, and the distroless Docker image.

Prerequisites:

• git on PATH
• gh only when skeeper init creates a new GitHub sidecar repo

🔄 How It Works

Spec files live in the main worktree but are ignored by the main repository through a managed .gitignore block. The sidecar repository stores mirrored files under <namespace>/<path> and pushes them to <namespace>/__branches__/<source-branch>.

On commit, the managed pre-commit block runs last. On automatic merge commits, the managed pre-merge-commit block runs the same strict sync path because Git does not run pre-commit for merge commits. Both hooks build a plan from the staged index plus explicitly owned ignored/untracked spec paths, fetch and rebase sidecar branches, mirror content into .skeeper/, commit and push the sidecar, write skeeper.lock, and stage that lock before Git creates the main commit.

flowchart TD
    Start([👤 git commit]):::user --> UserHook[🪝 Existing user hook content]:::user
    UserHook --> Block

    subgraph Block [📦 Skeeper pre-commit block]
        direction TB
        S1[🧮 Reconcile staged specs<br/>+ ownership] --> S2[🔄 Fetch &amp; rebase<br/>sidecar branch]
        S2 --> S3[🪞 Mirror namespace files<br/>into .skeeper/]
        S3 --> S4[📤 Commit &amp; push sidecar]
        S4 --> S5[🔒 Write &amp; stage<br/>skeeper.lock]
    end

    Block --> Commit[✅ Main commit proceeds]:::ok
    Commit --> Push([🚀 git push]):::user
    Push --> Verify[🔍 Skeeper pre-push verify]:::skeeper
    Verify --> Done([🎉 Sidecar verified]):::ok

    classDef user fill:#dbeafe,stroke:#1d4ed8,color:#0c1e3e
    classDef skeeper fill:#fef3c7,stroke:#b45309,color:#3b2c00
    classDef ok fill:#dcfce7,stroke:#15803d,color:#052e16
    class S1,S2,S3,S4,S5 skeeper

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If sync fails, the commit fails. This is intentional: a committed main change should not silently drift from the sidecar. The audited bypass is SKEEPER_SKIP=1; it records .git/skeeper/bypass.json, prints a warning, and pre-push, status, fsck, and verify continue to surface stale-lock diagnostics until skeeper sync repairs the state. git commit --no-verify is unsupported because Git skips all hook code and cannot record an audit trail.

⚙️ Configuration

skeeper init writes .skeeper.yml at the repository root. Commit it.

sidecar: git@github.com:user/myproject-specs.git

namespaces:
  - name: project
    patterns:
      - "**/SPEC.md"
      - "docs/specs/**"
      - ".claude/plans/**"
      - "**/*.spec.md"
    exclude:
      - "docs/specs/private/**"

Advanced operational defaults are optional:

settings:
  guardrails:
    max_files: 100
    max_bytes: 10485760
  hooks:
    pre_push_timeout: 30s
    allow_skip_env: SKEEPER_SKIP

namespaces:
  - name: generated
    patterns:
      - "generated/specs/**"
    respect_gitignore: false

Rules:

• Unknown keys are rejected.
• Every namespace needs a name and at least one glob in patterns.
• exclude is the only public exclusion mechanism. Negative globs in patterns are rejected.
• Ownership must be unique. If two namespaces own the same file, the plan fails and asks for an exclude fix.
• respect_gitignore: false bypasses root .gitignore, nested .gitignore, .git/info/exclude, and global excludes for that namespace. .git/ and .skeeper/ are always excluded.

Local-only state lives under .git/skeeper/:

File	Purpose
transaction.json	Current resumable mutating operation and phase
bypass.json	Latest audited strict-hook bypass

🚀 Quick Start

skeeper init

Interactive init asks for the sidecar mode, repository name or URL, namespace, bootstrap command, and optional extra context globs. With flags:

skeeper init \
  --sidecar-name myproject-specs \
  --visibility private \
  --namespace project \
  --patterns "**/SPEC.md" \
  --patterns "docs/specs/**"

Use an existing shared sidecar:

skeeper init \
  --sidecar git@github.com:user/shared-specs.git \
  --namespace project \
  --patterns "**/SPEC.md"

Then edit specs and commit normally:

$EDITOR src/auth/SPEC.md
git add src/auth/service.go src/auth/SPEC.md
git commit -m "auth: design OAuth provider flow"

The pre-commit and pre-merge-commit hooks mirror specs and stage skeeper.lock. If a hook stages a new lock, review it and include it in the commit.

🛟 Failed Sync Recovery

Inspect local repair state:

skeeper repair status

Resume the recorded operation when network/auth/sidecar contention has been fixed:

skeeper repair resume

Abort only before the main index has been mutated:

skeeper repair abort

Run a fresh repair sync when a bypass or stale lock is reported:

skeeper sync
skeeper verify

📖 CLI Reference

skeeper init [flags]
skeeper sync [--dry-run] [--json] [--commit --message <msg>] [--force]
skeeper adopt <path-or-glob>... [--dry-run] [--json] [--force] [--commit --message <msg>]
skeeper untrack <path-or-glob>... [--dry-run] [--json] [--force] [--commit --message <msg>]
skeeper pattern test <glob> [--namespace <name>] [--json]
skeeper pattern add <glob> [--namespace <name>] [--exclude <glob>]... [--adopt-existing] [--dry-run] [--json] [--force] [--commit --message <msg>]
skeeper hydrate
skeeper status [--json]
skeeper log <path> [--latest]
skeeper fsck [--json] [--source-branch <branch>]
skeeper verify [--json] [--source-branch <branch>]
skeeper hooks install [--json]
skeeper hooks check [--json]
skeeper merge-driver [--json]
skeeper repair status|resume|abort [--json]
skeeper version

Command notes:

• sync uses working-tree content and stages skeeper.lock. Hook mode uses staged index content.
• adopt and untrack push sidecar coverage before removing main-index tracking.
• pattern add --adopt-existing updates .skeeper.yml, updates the managed .gitignore block, then runs the same adoption transaction.
• verify checks skeeper.lock against the sidecar remote and does not require hooks.
• fsck compares current working-tree specs against locked sidecar content and does not mutate files or refs.
• hydrate restores from locked sidecar commits by default.
• log --latest fetches the namespace branch and reads its latest history instead of the locked commit.
• hooks install removes legacy Skeeper post-commit blocks, installs strict pre-commit/pre-merge-commit/pre-push blocks, writes .gitattributes, and configures the skeeper.lock merge driver.

🤖 CI Action

Use the same-repository Action to verify skeeper.lock in CI:

name: skeeper

on:
  pull_request:
  push:
    branches: [main]

jobs:
  verify:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
        with:
          fetch-depth: 0
      - uses: compozy/skeeper@v0.1.1
        with:
          args: |
            verify
            --json
          ssh-private-key: ${{ secrets.SKEEPER_SSH_PRIVATE_KEY }}

Credential precedence:

1. ssh-private-key writes a temp key and sets GIT_SSH_COMMAND.
2. token configures HTTPS GitHub credentials.
3. Existing runner Git/SSH credentials are used when neither input is provided.

Secrets are masked before configuration. The wrapper downloads the released Skeeper binary for the action ref/tag and delegates verification to the CLI.

🩺 Troubleshooting

SKEEPER_SKIP=1 was used

Run skeeper status, then skeeper sync, then skeeper verify. The bypass journal remains visible until sync clears it.

Sidecar push was rejected

Run skeeper repair status. If the failure happened before main-index mutation, fix network/auth or sidecar contention and run skeeper repair resume. If the main index was already mutated, inspect the listed files manually.

skeeper.lock conflicts during merge

Run skeeper hooks install to ensure the merge driver is configured, then rerun the merge. Manual editing of scalar sidecar SHAs is unsupported; regenerate the lock through skeeper merge-driver or skeeper sync.

verify reports a lock mismatch

The main commit and sidecar remote disagree. Run skeeper sync, include the updated skeeper.lock, and rerun skeeper verify.

A namespace overlaps another namespace

Move shared files into exactly one namespace by adding exclude: entries. Skeeper does not use order-based precedence.

🚫 When Skeeper Is the Wrong Tool

• Repositories where specs already belong in the main diff and reviewers explicitly want them inline.
• Teams that need PR review on the spec content itself before merge — Skeeper mirrors after the main commit succeeds, by design.
• Repositories without a stable sidecar Git host: Skeeper fails the commit when the sidecar is unreachable (the audited SKEEPER_SKIP=1 bypass exists, but it is not a substitute for a working remote).
• Storing build artifacts, generated code, or large binaries. Default guardrails cap mutating plans at 100 files and 10 MiB on purpose.

🛠️ Development

mise install
bun install
make hooks-install
make verify

Common targets:

make fmt
make lint
make test
make build
make cover
make release-snapshot

Contributor guidance, commit conventions, and agent instructions live in CLAUDE.md and AGENTS.md.

📄 License

MIT