diff --git a/.ai/stack-profiles/diffrat-cli.md b/.ai/stack-profiles/diffrat-cli.md
index ce85180..42f3be5 100644
--- a/.ai/stack-profiles/diffrat-cli.md
+++ b/.ai/stack-profiles/diffrat-cli.md
@@ -19,6 +19,7 @@ pytest
 ruff format --check src tests
 ruff check .
 mypy .
+bandit -r src/diffrat/checks.py src/diffrat/review_quality.py src/diffrat/scoring.py
 python -m diffrat --help
 diffrat --help
 ```
diff --git a/.github/workflows/validate-workflow-contracts.yml b/.github/workflows/validate-workflow-contracts.yml
index 5b6def7..673dc76 100644
--- a/.github/workflows/validate-workflow-contracts.yml
+++ b/.github/workflows/validate-workflow-contracts.yml
@@ -46,5 +46,12 @@ jobs:
       - name: Mypy
         run: mypy .
 
+      - name: Bandit
+        run: >
+          bandit -r
+          src/diffrat/checks.py
+          src/diffrat/review_quality.py
+          src/diffrat/scoring.py
+
       - name: Pytest
         run: pytest tests/ -q
diff --git a/CHANGELOG.md b/CHANGELOG.md
index be23394..675274e 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -9,6 +9,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Fixed
 
+- `--check` bandit false positives on Diffrat itself (`subprocess` import/run in
+  `checks.py`; pillar id `"maintainable"` in `review_quality.py`)
 - Track `.ai/ideas/implemented/` docs referenced by `decisions.md`
 
 ### Changed
@@ -18,6 +20,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   `./scripts/setup-ai-workflow.sh` first
 - CI runs `ruff format --check src tests`, `ruff check .`, and `mypy .` in
   addition to pytest (matches README / stack-profile quality gates)
+- CI / `[dev]` include `bandit` on `--check` dogfood modules (`checks.py`,
+  `review_quality.py`, `scoring.py`)
 - One-shot `ruff format` on `src/` and `tests/`
 
 ## [1.1.1] - 2026-08-09
diff --git a/README.md b/README.md
index 7bbfd7c..c265a65 100644
--- a/README.md
+++ b/README.md
@@ -339,6 +339,7 @@ pytest
 ruff format --check src tests
 ruff check .
 mypy .
+bandit -r src/diffrat/checks.py src/diffrat/review_quality.py src/diffrat/scoring.py
 ```
 
 ## Architecture and context
diff --git a/pyproject.toml b/pyproject.toml
index e7cd198..ce161ea 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -32,7 +32,7 @@ Issues = "https://github.com/szymoniwacz/diffrat/issues"
 Changelog = "https://github.com/szymoniwacz/diffrat/blob/main/CHANGELOG.md"
 
 [project.optional-dependencies]
-dev = ["pytest>=8.0", "mypy>=1.8", "ruff>=0.4"]
+dev = ["pytest>=8.0", "mypy>=1.8", "ruff>=0.4", "bandit>=1.7"]
 
 [project.scripts]
 diffrat = "diffrat.__main__:main"
diff --git a/src/diffrat/checks.py b/src/diffrat/checks.py
index 9fe49a9..8911b59 100644
--- a/src/diffrat/checks.py
+++ b/src/diffrat/checks.py
@@ -4,7 +4,7 @@
 
 import shlex
 import shutil
-import subprocess
+import subprocess  # nosec B404
 import sys
 from dataclasses import dataclass
 from pathlib import PurePosixPath
@@ -254,7 +254,7 @@ def run_checks(
                 )
             )
             continue
-        completed = subprocess.run(
+        completed = subprocess.run(  # nosec B603
             list(spec.argv),
             cwd=cwd,
             capture_output=True,
diff --git a/src/diffrat/review_quality.py b/src/diffrat/review_quality.py
index ebc2a16..23ee827 100644
--- a/src/diffrat/review_quality.py
+++ b/src/diffrat/review_quality.py
@@ -12,7 +12,10 @@
 PillarId = Literal["understand", "focused", "maintainable"]
 PillarStatus = Literal["ok", "warn", "risk"]
 
-_DEFAULT_PILLAR: PillarId = "maintainable"
+# Pillar id label (JSON/API contract); not a credential.
+PILLAR_MAINTAINABLE: PillarId = "maintainable"  # nosec B105
+
+_DEFAULT_PILLAR: PillarId = PILLAR_MAINTAINABLE
 
 
 @dataclass(frozen=True, slots=True)
@@ -43,7 +46,7 @@ class ReviewQualityPillarResult:
         label="One thing well",
     ),
     ReviewQualityPillar(
-        id="maintainable",
+        id=PILLAR_MAINTAINABLE,
         label="Safe to change in six months",
     ),
 )
@@ -66,22 +69,22 @@ class ReviewQualityPillarResult:
     "wip_commits": "focused",
     "mixed_concerns": "focused",
     # maintainable — safety, tests, dependencies, fragile patterns
-    "security_sensitive_paths": "maintainable",
-    "ci_workflow_paths": "maintainable",
-    "possible_secret": "maintainable",
-    "dangerous_call": "maintainable",
-    "config_or_deps": "maintainable",
-    "suspicious_constant_change": "maintainable",
-    "tests_touched": "maintainable",
-    "source_without_tests": "maintainable",
-    "source_heavy_without_tests": "maintainable",
-    "ci_without_tests": "maintainable",
-    "missing_test_file": "maintainable",
-    "lockfile_without_manifest": "maintainable",
-    "manifest_without_lockfile": "maintainable",
-    "debug_leftover": "maintainable",
-    "broad_exception": "maintainable",
-    "hardcoded_url_or_ip": "maintainable",
+    "security_sensitive_paths": PILLAR_MAINTAINABLE,
+    "ci_workflow_paths": PILLAR_MAINTAINABLE,
+    "possible_secret": PILLAR_MAINTAINABLE,
+    "dangerous_call": PILLAR_MAINTAINABLE,
+    "config_or_deps": PILLAR_MAINTAINABLE,
+    "suspicious_constant_change": PILLAR_MAINTAINABLE,
+    "tests_touched": PILLAR_MAINTAINABLE,
+    "source_without_tests": PILLAR_MAINTAINABLE,
+    "source_heavy_without_tests": PILLAR_MAINTAINABLE,
+    "ci_without_tests": PILLAR_MAINTAINABLE,
+    "missing_test_file": PILLAR_MAINTAINABLE,
+    "lockfile_without_manifest": PILLAR_MAINTAINABLE,
+    "manifest_without_lockfile": PILLAR_MAINTAINABLE,
+    "debug_leftover": PILLAR_MAINTAINABLE,
+    "broad_exception": PILLAR_MAINTAINABLE,
+    "hardcoded_url_or_ip": PILLAR_MAINTAINABLE,
 }
 
 
diff --git a/tests/test_bandit_self.py b/tests/test_bandit_self.py
new file mode 100644
index 0000000..378ad29
--- /dev/null
+++ b/tests/test_bandit_self.py
@@ -0,0 +1,28 @@
+"""Dogfood: bandit stays clean on modules that --check commonly scans."""
+
+from __future__ import annotations
+
+import shutil
+import subprocess
+from pathlib import Path
+
+import pytest
+
+_REPO_ROOT = Path(__file__).resolve().parents[1]
+_BANDIT_TARGETS = (
+    "src/diffrat/checks.py",
+    "src/diffrat/review_quality.py",
+    "src/diffrat/scoring.py",
+)
+
+
+@pytest.mark.skipif(shutil.which("bandit") is None, reason="bandit not installed")
+def test_bandit_clean_on_check_dogfood_modules() -> None:
+    completed = subprocess.run(
+        ["bandit", "-r", *_BANDIT_TARGETS],
+        cwd=_REPO_ROOT,
+        capture_output=True,
+        text=True,
+        check=False,
+    )
+    assert completed.returncode == 0, completed.stdout + completed.stderr