diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 9c8920f..b0966ca 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -60,3 +60,23 @@ jobs:
         run: python -m pip install --upgrade pip pyyaml pytest jsonschema langgraph
       - name: LangGraph recipe end-to-end
         run: python -B -m pytest -q -p no:cacheprovider scripts/test_langgraph_recipe.py
+
+  action-dogfood:
+    name: action (dogfood on flagship example)
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      # The repo root's live .loop/ is gitignored, so it does not exist in a fresh
+      # CI checkout — the tracked flagship example is the contract the action gates
+      # (doctor-clean, inspect 90/strong in the action's dependency-free install).
+      - uses: ./
+        with:
+          path: "examples/coverage-repair"
+          fail-under-score: "90"
+
+      - name: pre-commit consumer fixture
+        # bare `python` is on PATH here because the preceding `uses: ./` composite step ran setup-python
+        # (persisted via GITHUB_PATH) — keep the action step before this one.
+        run: |
+          python -m pip install --quiet pre-commit pytest pyyaml
+          python -B -m pytest -q -p no:cacheprovider scripts/test_precommit_hook.py
diff --git a/.pre-commit-hooks.yaml b/.pre-commit-hooks.yaml
new file mode 100644
index 0000000..a992d6b
--- /dev/null
+++ b/.pre-commit-hooks.yaml
@@ -0,0 +1,7 @@
+- id: loop-doctor
+  name: loop doctor (loop-contract validity gate)
+  description: "Validate the repo's .loop/ contract objects; fails on a dishonest or malformed contract."
+  entry: loop doctor .
+  language: python
+  pass_filenames: false
+  always_run: true
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 6116702..dc2b415 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -61,6 +61,32 @@ firewall never locks a session — and a strict no-op for every repo without a
   (`python3 ${CLAUDE_PLUGIN_ROOT}/hooks/stop_firewall.py`), so a marketplace
   install gets the firewall with zero configuration.
 
+**C1 — the CI gate.** The proof-of-done gate at the two boundaries where a
+foreign repo already runs its checks: a GitHub Action for pull-request CI and a
+pre-commit hook for the local commit. Both wrap the same `loop doctor` honesty
+gate the runtime enforces, so a consumer adopts the wedge without adopting the
+loop-engineer runtime — and the repo dogfoods both on its own contract in CI.
+
+### Added
+- **Composite GitHub Action** (`action.yml`, id `loop-engineer gate`) — runs
+  `loop doctor` as a hard gate and `loop inspect` as a scorecard (warn-only until
+  `fail-under-score` is set), installing loop-engineer from PyPI (`version:`) or
+  from the action's own checkout by default. Writes the scorecard to the job
+  summary and, given a `github-token`, an optional PR comment. The `action-dogfood`
+  CI job runs it against the tracked flagship example contract
+  (`examples/coverage-repair`) at `fail-under-score: 90` — the repo root's live
+  `.loop/` is gitignored and absent in a fresh CI checkout.
+- **`.pre-commit-hooks.yaml`** — a `language: python` hook id `loop-doctor`
+  (`entry: loop doctor .`, `always_run`, `pass_filenames: false`) that a consumer
+  wires in with three lines of `.pre-commit-config.yaml`; PR1's self-contained
+  wheel is what makes the `language: python` install work from any consumer repo.
+- **Pre-commit acceptance test** (`scripts/test_precommit_hook.py`) — asserts the
+  hook definition is sound and its entry matches a declared console script, plus a
+  consumer-fixture path that scaffolds a fresh contract and runs the hook through
+  `pre-commit try-repo` end-to-end. Env-guarded on the `pre-commit` tool (skips
+  when absent); the `action-dogfood` CI job installs it and runs the fixture for
+  real on the PR checkout.
+
 ## 0.6.1 — 2026-07-04
 
 **PyPI substrate.** `loop-engineer` becomes a self-contained wheel that runs from
diff --git a/action.yml b/action.yml
new file mode 100644
index 0000000..11de31e
--- /dev/null
+++ b/action.yml
@@ -0,0 +1,98 @@
+name: "loop-engineer gate"
+description: "Proof-of-done gate for agent-loop contracts: hard-fails on doctor, scores with inspect (warn-only by default)."
+branding:
+  icon: "check-circle"
+  color: "green"
+
+inputs:
+  path:
+    description: "Workspace (or .loop dir) holding the loop contract"
+    required: false
+    default: "."
+  version:
+    description: "loop-engineer version to install from PyPI (e.g. 0.6.1). Empty installs from the action's own checkout."
+    required: false
+    default: ""
+  fail-under-score:
+    description: "Fail the job when the inspect score (0-100) is below this. 0 keeps inspect warn-only."
+    required: false
+    default: "0"
+  python-version:
+    description: "Python version for the gate"
+    required: false
+    default: "3.12"
+  github-token:
+    description: "Token for the optional PR scorecard comment. Empty skips the comment."
+    required: false
+    default: ""
+
+runs:
+  using: "composite"
+  steps:
+    - uses: actions/setup-python@v5
+      with:
+        python-version: ${{ inputs.python-version }}
+
+    - name: Install loop-engineer
+      shell: bash
+      env:
+        LOOP_VERSION: "${{ inputs.version }}"
+      run: |
+        if [ -n "$LOOP_VERSION" ]; then
+          python -m pip install --quiet "loop-engineer==$LOOP_VERSION"
+        else
+          python -m pip install --quiet "${{ github.action_path }}"
+        fi
+
+    - name: loop doctor (hard gate)
+      shell: bash
+      env:
+        LOOP_PATH: "${{ inputs.path }}"
+      run: loop doctor "$LOOP_PATH"
+
+    - name: loop inspect (scorecard)
+      shell: bash
+      env:
+        LOOP_PATH: "${{ inputs.path }}"
+        LOOP_FAIL_UNDER: "${{ inputs.fail-under-score }}"
+      run: |
+        set +e
+        loop inspect "$LOOP_PATH" > "${RUNNER_TEMP}/inspect.json"
+        set -e
+        python - "${RUNNER_TEMP}/inspect.json" "$LOOP_FAIL_UNDER" <<'PY'
+        import json, os, sys
+
+        report = json.load(open(sys.argv[1]))
+        fail_under = int(sys.argv[2])
+        score, verdict = report.get("score", 0), report.get("verdict", "?")
+        lines = [
+            "## loop-engineer scorecard",
+            "",
+            f"| metric | value |",
+            f"|---|---|",
+            f"| verdict | **{verdict}** |",
+            f"| score | {score}/100 |",
+            f"| gaps | {len(report.get('gaps', []))} |",
+            "",
+        ]
+        for gap in report.get("gaps", [])[:10]:
+            lines.append(f"- {gap}")
+        summary = "\n".join(lines) + "\n"
+        with open(os.environ["GITHUB_STEP_SUMMARY"], "a", encoding="utf-8") as fh:
+            fh.write(summary)
+        open(os.path.join(os.environ["RUNNER_TEMP"], "scorecard.md"), "w", encoding="utf-8").write(summary)
+        if verdict == "weak":
+            print(f"::warning::loop inspect verdict is weak (score {score}/100)")
+        if fail_under and score < fail_under:
+            print(f"::error::inspect score {score} < fail-under-score {fail_under}")
+            raise SystemExit(1)
+        PY
+
+    - name: PR scorecard comment (optional)
+      if: ${{ inputs.github-token != '' && github.event_name == 'pull_request' }}
+      shell: bash
+      env:
+        GH_TOKEN: ${{ inputs.github-token }}
+      run: |
+        gh api "repos/${GITHUB_REPOSITORY}/issues/${{ github.event.pull_request.number }}/comments" \
+          -f body="$(cat "${RUNNER_TEMP}/scorecard.md")" || echo "::warning::PR comment failed (non-fatal)"
diff --git a/scripts/test_precommit_hook.py b/scripts/test_precommit_hook.py
new file mode 100644
index 0000000..03533e3
--- /dev/null
+++ b/scripts/test_precommit_hook.py
@@ -0,0 +1,49 @@
+"""C1 acceptance: the pre-commit hook definition is sound (always), and it runs
+from a consumer-side .pre-commit-config.yaml fixture (env-guarded on the
+pre-commit tool; the CI dogfood job installs it and runs this for real)."""
+
+from __future__ import annotations
+
+import shutil
+import subprocess
+import sys
+from pathlib import Path
+
+import pytest
+
+REPO_ROOT = Path(__file__).resolve().parent.parent
+
+sys.path.insert(0, str(REPO_ROOT))
+from loop.scaffold import scaffold  # noqa: E402
+
+
+def _hooks() -> list[dict]:
+    yaml = pytest.importorskip("yaml")
+    return yaml.safe_load((REPO_ROOT / ".pre-commit-hooks.yaml").read_text(encoding="utf-8"))
+
+
+def test_hook_definition_is_sound():
+    (hook,) = _hooks()
+    assert hook["id"] == "loop-doctor"
+    assert hook["entry"] == "loop doctor ."
+    assert hook["language"] == "python"
+    assert hook["pass_filenames"] is False
+    assert hook["always_run"] is True
+
+
+def test_entry_command_matches_a_declared_console_script():
+    text = (REPO_ROOT / "pyproject.toml").read_text(encoding="utf-8")
+    assert 'loop = "loop.__main__:main"' in text
+
+
+@pytest.mark.skipif(shutil.which("pre-commit") is None, reason="pre-commit tool not installed")
+def test_hook_runs_from_a_consumer_fixture(tmp_path):
+    consumer = tmp_path / "consumer"
+    scaffold(consumer)
+    subprocess.run(["git", "init", "-q"], cwd=consumer, check=True)
+    subprocess.run(["git", "add", "-A"], cwd=consumer, check=True)
+    proc = subprocess.run(
+        ["pre-commit", "try-repo", str(REPO_ROOT), "loop-doctor", "--all-files"],
+        cwd=consumer, capture_output=True, text=True, timeout=600,
+    )
+    assert proc.returncode == 0, proc.stdout + proc.stderr