From 751b0d50230f3c979f46fae6309d2fac66c5ff64 Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Sat, 4 Jul 2026 06:34:30 +0000
Subject: [PATCH 1/7] Initial plan


From 3b6e9a06c93cac15a86012d1c974fa16c7185c1e Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Sat, 4 Jul 2026 06:37:00 +0000
Subject: [PATCH 2/7] feat: add quality ratchet (baseline + check script +
 workflow)

- Add .quality-baseline.json capturing current ruff violation counts per file
- Add .github/scripts/check_quality.py to compare PR vs baseline
- Add .github/workflows/quality-ratchet.yml triggered on pull_request

Implements DRC recommendation from issue #159: zero-upfront-refactoring
ratchet that prevents new violations while allowing organic debt erosion.
---
 .github/scripts/check_quality.py      | 155 ++++++++++++++++++++++++++
 .github/workflows/quality-ratchet.yml |  89 +++++++++++++++
 .quality-baseline.json                |  14 +++
 3 files changed, 258 insertions(+)
 create mode 100644 .github/scripts/check_quality.py
 create mode 100644 .github/workflows/quality-ratchet.yml
 create mode 100644 .quality-baseline.json

diff --git a/.github/scripts/check_quality.py b/.github/scripts/check_quality.py
new file mode 100644
index 0000000..6ac7bc2
--- /dev/null
+++ b/.github/scripts/check_quality.py
@@ -0,0 +1,155 @@
+"""Quality ratchet: compare current ruff violations against a committed baseline.
+
+Exit codes:
+  0 — no regressions (violations per file ≤ baseline)
+  1 — regressions detected (at least one file has more violations than baseline)
+
+Usage:
+  python .github/scripts/check_quality.py [--baseline .quality-baseline.json]
+"""
+
+from __future__ import annotations
+
+import argparse
+import collections
+import json
+import os
+import subprocess
+import sys
+from pathlib import Path
+
+
+def run_ruff(repo_root: Path) -> dict[str, int]:
+    """Run ruff and return per-file violation counts (relative paths)."""
+    result = subprocess.run(
+        ["ruff", "check", ".", "--output-format=json"],
+        cwd=repo_root,
+        capture_output=True,
+        text=True,
+    )
+    # ruff exits 1 when violations found; that is expected
+    try:
+        data = json.loads(result.stdout)
+    except json.JSONDecodeError:
+        print("❌ Failed to parse ruff JSON output.", file=sys.stderr)
+        print(result.stderr, file=sys.stderr)
+        sys.exit(1)
+
+    root_prefix = str(repo_root) + os.sep
+    counts: dict[str, int] = collections.Counter()
+    for item in data:
+        rel = item["filename"].replace(root_prefix, "")
+        counts[rel] += 1
+    return dict(counts)
+
+
+def load_baseline(path: Path) -> dict[str, int]:
+    """Load the committed baseline file."""
+    if not path.exists():
+        print(f"❌ Baseline file not found: {path}", file=sys.stderr)
+        print("   Run: python .github/scripts/check_quality.py --update-baseline", file=sys.stderr)
+        sys.exit(1)
+    data = json.loads(path.read_text())
+    return data.get("per_file", {})
+
+
+def compare(current: dict[str, int], baseline: dict[str, int]) -> tuple[list[str], list[str]]:
+    """Return (regressions, improvements).
+
+    A regression is any file whose current count exceeds its baseline count.
+    A new file with violations (absent from baseline) is also a regression.
+    """
+    all_files = set(current) | set(baseline)
+    regressions: list[str] = []
+    improvements: list[str] = []
+
+    for f in sorted(all_files):
+        curr = current.get(f, 0)
+        base = baseline.get(f, 0)
+        if curr > base:
+            regressions.append(f"  ❌  {f}  ({base} → {curr}, +{curr - base})")
+        elif curr < base:
+            improvements.append(f"  ✅  {f}  ({base} → {curr}, -{base - curr})")
+
+    return regressions, improvements
+
+
+def update_baseline(repo_root: Path, baseline_path: Path) -> None:
+    """Regenerate the baseline from the current ruff output and write it."""
+    import datetime
+
+    result = subprocess.run(
+        ["ruff", "--version"], capture_output=True, text=True
+    )
+    ruff_version = result.stdout.strip().replace("ruff ", "")
+
+    current = run_ruff(repo_root)
+    data = {
+        "generated_at": datetime.datetime.now(datetime.UTC).isoformat(timespec="seconds"),
+        "ruff_version": ruff_version,
+        "total_violations": sum(current.values()),
+        "per_file": dict(sorted(current.items())),
+    }
+    baseline_path.write_text(json.dumps(data, indent=2) + "\n")
+    print(f"✅ Baseline updated: {sum(current.values())} violations across {len(current)} files")
+    print(f"   Written to {baseline_path}")
+
+
+def main() -> None:
+    parser = argparse.ArgumentParser(description=__doc__)
+    parser.add_argument(
+        "--baseline",
+        default=".quality-baseline.json",
+        help="Path to baseline JSON file (default: .quality-baseline.json)",
+    )
+    parser.add_argument(
+        "--update-baseline",
+        action="store_true",
+        help="Regenerate the baseline from current state and exit 0",
+    )
+    args = parser.parse_args()
+
+    repo_root = Path(__file__).resolve().parents[2]
+    baseline_path = repo_root / args.baseline
+
+    if args.update_baseline:
+        update_baseline(repo_root, baseline_path)
+        return
+
+    baseline = load_baseline(baseline_path)
+    current = run_ruff(repo_root)
+
+    total_baseline = sum(baseline.values())
+    total_current = sum(current.values())
+    regressions, improvements = compare(current, baseline)
+
+    print("=" * 60)
+    print("  Quality Ratchet Report")
+    print("=" * 60)
+    print(f"  Baseline violations : {total_baseline}")
+    print(f"  Current  violations : {total_current}")
+    delta = total_current - total_baseline
+    delta_str = f"+{delta}" if delta > 0 else str(delta)
+    print(f"  Delta               : {delta_str}")
+    print()
+
+    if improvements:
+        print(f"Improvements ({len(improvements)} file(s)):")
+        print("\n".join(improvements))
+        print()
+
+    if regressions:
+        print(f"Regressions ({len(regressions)} file(s)) — BLOCKING:")
+        print("\n".join(regressions))
+        print()
+        print("Fix the regressions above, or run:")
+        print("  ruff check <file> --fix")
+        print()
+        print("❌ Quality ratchet FAILED — this PR introduces new violations.")
+        sys.exit(1)
+
+    print("✅ Quality ratchet PASSED — no new violations introduced.")
+
+
+if __name__ == "__main__":
+    main()
diff --git a/.github/workflows/quality-ratchet.yml b/.github/workflows/quality-ratchet.yml
new file mode 100644
index 0000000..e4e9ead
--- /dev/null
+++ b/.github/workflows/quality-ratchet.yml
@@ -0,0 +1,89 @@
+name: Quality Ratchet
+
+on:
+  pull_request:
+    types: [opened, synchronize, ready_for_review]
+    paths:
+      - '**.py'
+      - 'pyproject.toml'
+      - '.quality-baseline.json'
+
+permissions:
+  contents: read
+  pull-requests: write
+
+jobs:
+  ratchet:
+    name: ruff ratchet (no new violations)
+    runs-on: ubuntu-latest
+    timeout-minutes: 10
+
+    steps:
+      - name: Checkout PR head
+        uses: actions/checkout@v5
+
+      - name: Set up Python
+        uses: actions/setup-python@v6
+        with:
+          python-version: '3.11'
+          cache: 'pip'
+
+      - name: Install ruff
+        run: pip install "ruff==0.15.20"
+
+      - name: Run quality ratchet
+        id: ratchet
+        run: python .github/scripts/check_quality.py
+        continue-on-error: true
+
+      - name: Comment on PR
+        if: github.event_name == 'pull_request'
+        uses: actions/github-script@v8
+        with:
+          script: |
+            const outcome = '${{ steps.ratchet.outcome }}';
+            const passed  = outcome === 'success';
+
+            const header = passed
+              ? '## ✅ Quality Ratchet — PASSED'
+              : '## ❌ Quality Ratchet — FAILED';
+
+            const body = passed
+              ? `${header}\n\nNo new ruff violations introduced by this PR. 🎉`
+              : `${header}\n\nThis PR introduces new ruff violations compared to the baseline.\n\n` +
+                `Run \`python .github/scripts/check_quality.py\` locally to see the details, ` +
+                `then fix the regressions or run \`ruff check <file> --fix\` to auto-fix them.\n\n` +
+                `> **Tip:** You can improve the baseline by fixing existing violations in the ` +
+                `files you touch, then updating it with:\n` +
+                `> \`python .github/scripts/check_quality.py --update-baseline\``;
+
+            const { data: comments } = await github.rest.issues.listComments({
+              owner: context.repo.owner,
+              repo:  context.repo.repo,
+              issue_number: context.issue.number,
+            });
+
+            const existing = comments.find(c =>
+              c.user.login === 'github-actions[bot]' &&
+              c.body.includes('Quality Ratchet')
+            );
+
+            if (existing) {
+              await github.rest.issues.updateComment({
+                owner:      context.repo.owner,
+                repo:       context.repo.repo,
+                comment_id: existing.id,
+                body:       body,
+              });
+            } else {
+              await github.rest.issues.createComment({
+                owner:        context.repo.owner,
+                repo:         context.repo.repo,
+                issue_number: context.issue.number,
+                body:         body,
+              });
+            }
+
+      - name: Fail if ratchet failed
+        if: steps.ratchet.outcome == 'failure'
+        run: exit 1
diff --git a/.quality-baseline.json b/.quality-baseline.json
new file mode 100644
index 0000000..63e6fe5
--- /dev/null
+++ b/.quality-baseline.json
@@ -0,0 +1,14 @@
+{
+  "generated_at": "2026-07-04T06:36:49+00:00",
+  "ruff_version": "0.15.20",
+  "total_violations": 24,
+  "per_file": {
+    ".github/scripts/generate_rollback_manifest.py": 1,
+    "autopilot/staleness_engine.py": 5,
+    "tests/test_autonomous_agents.py": 6,
+    "tests/unit/test_dependency_agent.py": 1,
+    "tests/unit/test_security_scan_agent.py": 2,
+    "tests/unit/test_staleness_engine.py": 3,
+    "tests/unit/test_triage_agent.py": 6
+  }
+}

From 9a706b67d494231bc0a84bdc4c4741e6fea28726 Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Sat, 4 Jul 2026 06:38:35 +0000
Subject: [PATCH 3/7] fix: address code review feedback on quality ratchet

- Move datetime import to module level in check_quality.py
- Extract RUFF_VERSION env var in quality-ratchet.yml workflow
- Simplify JS failure message to single template literal
---
 .github/scripts/check_quality.py      |  3 +--
 .github/workflows/quality-ratchet.yml | 19 ++++++++++++-------
 2 files changed, 13 insertions(+), 9 deletions(-)

diff --git a/.github/scripts/check_quality.py b/.github/scripts/check_quality.py
index 6ac7bc2..ec2cd88 100644
--- a/.github/scripts/check_quality.py
+++ b/.github/scripts/check_quality.py
@@ -12,6 +12,7 @@
 
 import argparse
 import collections
+import datetime
 import json
 import os
 import subprocess
@@ -76,8 +77,6 @@ def compare(current: dict[str, int], baseline: dict[str, int]) -> tuple[list[str
 
 def update_baseline(repo_root: Path, baseline_path: Path) -> None:
     """Regenerate the baseline from the current ruff output and write it."""
-    import datetime
-
     result = subprocess.run(
         ["ruff", "--version"], capture_output=True, text=True
     )
diff --git a/.github/workflows/quality-ratchet.yml b/.github/workflows/quality-ratchet.yml
index e4e9ead..a8c04ee 100644
--- a/.github/workflows/quality-ratchet.yml
+++ b/.github/workflows/quality-ratchet.yml
@@ -12,6 +12,9 @@ permissions:
   contents: read
   pull-requests: write
 
+env:
+  RUFF_VERSION: '0.15.20'
+
 jobs:
   ratchet:
     name: ruff ratchet (no new violations)
@@ -29,7 +32,7 @@ jobs:
           cache: 'pip'
 
       - name: Install ruff
-        run: pip install "ruff==0.15.20"
+        run: pip install "ruff==${{ env.RUFF_VERSION }}"
 
       - name: Run quality ratchet
         id: ratchet
@@ -50,12 +53,14 @@ jobs:
 
             const body = passed
               ? `${header}\n\nNo new ruff violations introduced by this PR. 🎉`
-              : `${header}\n\nThis PR introduces new ruff violations compared to the baseline.\n\n` +
-                `Run \`python .github/scripts/check_quality.py\` locally to see the details, ` +
-                `then fix the regressions or run \`ruff check <file> --fix\` to auto-fix them.\n\n` +
-                `> **Tip:** You can improve the baseline by fixing existing violations in the ` +
-                `files you touch, then updating it with:\n` +
-                `> \`python .github/scripts/check_quality.py --update-baseline\``;
+              : `${header}
+
+This PR introduces new ruff violations compared to the baseline.
+
+Run \`python .github/scripts/check_quality.py\` locally to see the details, then fix the regressions or run \`ruff check <file> --fix\` to auto-fix them.
+
+> **Tip:** You can improve the baseline by fixing existing violations in the files you touch, then updating it with:
+> \`python .github/scripts/check_quality.py --update-baseline\``;
 
             const { data: comments } = await github.rest.issues.listComments({
               owner: context.repo.owner,

From 5cfb973ee28ddc148bb916dc313a1cfe97d2a0f8 Mon Sep 17 00:00:00 2001
From: "github-actions[bot]" <github-actions[bot]@users.noreply.github.com>
Date: Sat, 4 Jul 2026 06:42:11 +0000
Subject: [PATCH 4/7] style: auto-fix pre-commit issues [skip ci]

---
 .github/scripts/check_quality.py | 21 ++++++++++++++-------
 1 file changed, 14 insertions(+), 7 deletions(-)

diff --git a/.github/scripts/check_quality.py b/.github/scripts/check_quality.py
index ec2cd88..78e3c30 100644
--- a/.github/scripts/check_quality.py
+++ b/.github/scripts/check_quality.py
@@ -48,13 +48,18 @@ def load_baseline(path: Path) -> dict[str, int]:
     """Load the committed baseline file."""
     if not path.exists():
         print(f"❌ Baseline file not found: {path}", file=sys.stderr)
-        print("   Run: python .github/scripts/check_quality.py --update-baseline", file=sys.stderr)
+        print(
+            "   Run: python .github/scripts/check_quality.py --update-baseline",
+            file=sys.stderr,
+        )
         sys.exit(1)
     data = json.loads(path.read_text())
     return data.get("per_file", {})
 
 
-def compare(current: dict[str, int], baseline: dict[str, int]) -> tuple[list[str], list[str]]:
+def compare(
+    current: dict[str, int], baseline: dict[str, int]
+) -> tuple[list[str], list[str]]:
     """Return (regressions, improvements).
 
     A regression is any file whose current count exceeds its baseline count.
@@ -77,20 +82,22 @@ def compare(current: dict[str, int], baseline: dict[str, int]) -> tuple[list[str
 
 def update_baseline(repo_root: Path, baseline_path: Path) -> None:
     """Regenerate the baseline from the current ruff output and write it."""
-    result = subprocess.run(
-        ["ruff", "--version"], capture_output=True, text=True
-    )
+    result = subprocess.run(["ruff", "--version"], capture_output=True, text=True)
     ruff_version = result.stdout.strip().replace("ruff ", "")
 
     current = run_ruff(repo_root)
     data = {
-        "generated_at": datetime.datetime.now(datetime.UTC).isoformat(timespec="seconds"),
+        "generated_at": datetime.datetime.now(datetime.UTC).isoformat(
+            timespec="seconds"
+        ),
         "ruff_version": ruff_version,
         "total_violations": sum(current.values()),
         "per_file": dict(sorted(current.items())),
     }
     baseline_path.write_text(json.dumps(data, indent=2) + "\n")
-    print(f"✅ Baseline updated: {sum(current.values())} violations across {len(current)} files")
+    print(
+        f"✅ Baseline updated: {sum(current.values())} violations across {len(current)} files"
+    )
     print(f"   Written to {baseline_path}")
 
 

From d63dcb8795426842353f92db2fcf7999ed7c94a6 Mon Sep 17 00:00:00 2001
From: Gadget Lab <232155002+labgadget015-dotcom@users.noreply.github.com>
Date: Sat, 4 Jul 2026 08:26:39 +0100
Subject: [PATCH 5/7] Potential fix for pull request finding

Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>
---
 .github/scripts/check_quality.py | 38 ++++++++++++++++++++++++--------
 1 file changed, 29 insertions(+), 9 deletions(-)

diff --git a/.github/scripts/check_quality.py b/.github/scripts/check_quality.py
index 78e3c30..d0bf7ae 100644
--- a/.github/scripts/check_quality.py
+++ b/.github/scripts/check_quality.py
@@ -22,25 +22,45 @@
 
 def run_ruff(repo_root: Path) -> dict[str, int]:
     """Run ruff and return per-file violation counts (relative paths)."""
-    result = subprocess.run(
-        ["ruff", "check", ".", "--output-format=json"],
-        cwd=repo_root,
-        capture_output=True,
-        text=True,
-    )
+    try:
+        result = subprocess.run(
+            ["ruff", "check", ".", "--output-format=json"],
+            cwd=repo_root,
+            capture_output=True,
+            text=True,
+        )
+    except FileNotFoundError:
+        print(
+            "❌ ruff is not installed or not on PATH. Install it with: pip install ruff",
+            file=sys.stderr,
+        )
+        sys.exit(1)
+
     # ruff exits 1 when violations found; that is expected
     try:
         data = json.loads(result.stdout)
     except json.JSONDecodeError:
         print("❌ Failed to parse ruff JSON output.", file=sys.stderr)
-        print(result.stderr, file=sys.stderr)
+        if result.stdout.strip():
+            print(result.stdout, file=sys.stderr)
+        if result.stderr.strip():
+            print(result.stderr, file=sys.stderr)
         sys.exit(1)
 
-    root_prefix = str(repo_root) + os.sep
     counts: dict[str, int] = collections.Counter()
+    repo_root_resolved = repo_root.resolve()
     for item in data:
-        rel = item["filename"].replace(root_prefix, "")
+        filename = item.get("filename", "")
+        p = Path(filename)
+        if p.is_absolute():
+            try:
+                rel = p.resolve().relative_to(repo_root_resolved).as_posix()
+            except ValueError:
+                rel = p.as_posix()
+        else:
+            rel = p.as_posix()
         counts[rel] += 1
+
     return dict(counts)
 
 

From 4e6cae2d1ecce8f23329fdae11c13f184d23e96a Mon Sep 17 00:00:00 2001
From: Gadget Lab <232155002+labgadget015-dotcom@users.noreply.github.com>
Date: Sat, 4 Jul 2026 08:27:01 +0100
Subject: [PATCH 6/7] Potential fix for pull request finding

Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>
---
 .github/scripts/check_quality.py | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/.github/scripts/check_quality.py b/.github/scripts/check_quality.py
index d0bf7ae..05c68ce 100644
--- a/.github/scripts/check_quality.py
+++ b/.github/scripts/check_quality.py
@@ -73,8 +73,19 @@ def load_baseline(path: Path) -> dict[str, int]:
             file=sys.stderr,
         )
         sys.exit(1)
-    data = json.loads(path.read_text())
-    return data.get("per_file", {})
+
+    try:
+        data = json.loads(path.read_text())
+    except json.JSONDecodeError as e:
+        print(f"❌ Failed to parse baseline JSON: {path} ({e})", file=sys.stderr)
+        sys.exit(1)
+
+    per_file = data.get("per_file", {})
+    if not isinstance(per_file, dict):
+        print(f"❌ Baseline file has invalid 'per_file' shape: {path}", file=sys.stderr)
+        sys.exit(1)
+
+    return per_file
 
 
 def compare(

From 34c4d68e82ea0c5bec82acb920400265b20621ea Mon Sep 17 00:00:00 2001
From: "github-actions[bot]" <github-actions[bot]@users.noreply.github.com>
Date: Sat, 4 Jul 2026 07:27:06 +0000
Subject: [PATCH 7/7] style: auto-fix pre-commit issues [skip ci]

---
 .github/scripts/check_quality.py              |  1 -
 .github/scripts/generate_rollback_manifest.py |  4 ++--
 autopilot/staleness_engine.py                 | 10 +++++-----
 tests/test_autonomous_agents.py               | 10 ++++------
 tests/unit/test_dependency_agent.py           |  1 -
 tests/unit/test_security_scan_agent.py        |  2 --
 tests/unit/test_staleness_engine.py           |  8 +++-----
 tests/unit/test_triage_agent.py               | 13 +++++++------
 8 files changed, 21 insertions(+), 28 deletions(-)

diff --git a/.github/scripts/check_quality.py b/.github/scripts/check_quality.py
index 05c68ce..3c4c2fb 100644
--- a/.github/scripts/check_quality.py
+++ b/.github/scripts/check_quality.py
@@ -14,7 +14,6 @@
 import collections
 import datetime
 import json
-import os
 import subprocess
 import sys
 from pathlib import Path
diff --git a/.github/scripts/generate_rollback_manifest.py b/.github/scripts/generate_rollback_manifest.py
index 54dcb7a..c7c9de9 100644
--- a/.github/scripts/generate_rollback_manifest.py
+++ b/.github/scripts/generate_rollback_manifest.py
@@ -7,7 +7,7 @@
 """
 
 import os
-from datetime import datetime, timezone
+from datetime import UTC, datetime
 
 
 def main():
@@ -17,7 +17,7 @@ def main():
     author = os.environ.get("AUTHOR", "unknown")
     files_changed = os.environ.get("FILES_CHANGED", "").split()
 
-    timestamp = datetime.now(timezone.utc).strftime("%Y-%m-%d %H:%M UTC")
+    timestamp = datetime.now(UTC).strftime("%Y-%m-%d %H:%M UTC")
 
     path = "docs/ROLLBACK.md"
     os.makedirs("docs", exist_ok=True)
diff --git a/autopilot/staleness_engine.py b/autopilot/staleness_engine.py
index 5df6cb8..ff98769 100644
--- a/autopilot/staleness_engine.py
+++ b/autopilot/staleness_engine.py
@@ -26,7 +26,7 @@
 import logging
 import os
 import sys
-from datetime import datetime, timezone
+from datetime import UTC, datetime
 from pathlib import Path
 from typing import Any
 
@@ -204,7 +204,7 @@ def generate_comment(
                 cost = result.get("usage", {})
                 self._cost_log.append(
                     {
-                        "timestamp": datetime.now(timezone.utc).isoformat(),
+                        "timestamp": datetime.now(UTC).isoformat(),
                         "repo": repo_full_name,
                         "tier": tier,
                         "usage": cost,
@@ -231,7 +231,7 @@ def scan_repos(self, repos: list[dict[str, Any]]) -> list[dict[str, Any]]:
             repo_full_name, pr_number, pr_title, pr_url, age_days, tier
         """
         stale: list[dict[str, Any]] = []
-        now = datetime.now(timezone.utc)
+        now = datetime.now(UTC)
 
         for repo_cfg in repos:
             owner = repo_cfg["owner"]
@@ -243,7 +243,7 @@ def scan_repos(self, repos: list[dict[str, Any]]) -> list[dict[str, Any]]:
                 for pr in pulls:
                     created = pr.created_at
                     if created.tzinfo is None:
-                        created = created.replace(tzinfo=timezone.utc)
+                        created = created.replace(tzinfo=UTC)
                     age_days = (now - created).days
                     tier = self.assign_tier(age_days)
                     if tier > 0:
@@ -291,7 +291,7 @@ def process_stale_prs(
         Returns a summary dict with counts and per-PR actions taken.
         """
         state = self.load_state()
-        now_iso = datetime.now(timezone.utc).isoformat()
+        now_iso = datetime.now(UTC).isoformat()
         actions: list[dict[str, Any]] = []
 
         for pr_info in stale_prs:
diff --git a/tests/test_autonomous_agents.py b/tests/test_autonomous_agents.py
index 4a88150..822dc8c 100644
--- a/tests/test_autonomous_agents.py
+++ b/tests/test_autonomous_agents.py
@@ -1,8 +1,7 @@
 """Tests for autonomous_agent package — agents and CLI."""
 
-import re
-from datetime import datetime, timezone
-from unittest.mock import AsyncMock, MagicMock, Mock, patch
+from datetime import UTC, datetime
+from unittest.mock import Mock, patch
 
 import pytest
 from click.testing import CliRunner
@@ -20,7 +19,6 @@
     main,
 )
 
-
 # ── helpers ───────────────────────────────────────────────────────────────────
 
 
@@ -73,7 +71,7 @@ async def test_execute_stale_branch_requires_approval(self):
 
         branch = Mock()
         branch.name = "old-feature"
-        old_date = datetime(2025, 1, 1, tzinfo=timezone.utc)
+        old_date = datetime(2025, 1, 1, tzinfo=UTC)
         branch.commit.commit.author.date = old_date
         repo.get_branches.return_value = [branch]
         self.github.get_repository.return_value = repo
@@ -92,7 +90,7 @@ async def test_execute_stale_branch_auto_delete(self):
 
         branch = Mock()
         branch.name = "old-feature"
-        old_date = datetime(2025, 1, 1, tzinfo=timezone.utc)
+        old_date = datetime(2025, 1, 1, tzinfo=UTC)
         branch.commit.commit.author.date = old_date
         branch.commit.sha = "abc123"
 
diff --git a/tests/unit/test_dependency_agent.py b/tests/unit/test_dependency_agent.py
index c385473..52641f0 100644
--- a/tests/unit/test_dependency_agent.py
+++ b/tests/unit/test_dependency_agent.py
@@ -4,7 +4,6 @@
 
 import asyncio
 import json
-from pathlib import Path
 from unittest.mock import AsyncMock, MagicMock, patch
 
 
diff --git a/tests/unit/test_security_scan_agent.py b/tests/unit/test_security_scan_agent.py
index a7702af..d0fb780 100644
--- a/tests/unit/test_security_scan_agent.py
+++ b/tests/unit/test_security_scan_agent.py
@@ -4,8 +4,6 @@
 
 import asyncio
 import json
-import tempfile
-from pathlib import Path
 from unittest.mock import AsyncMock, MagicMock, mock_open, patch
 
 
diff --git a/tests/unit/test_staleness_engine.py b/tests/unit/test_staleness_engine.py
index 5f47706..5a735e9 100644
--- a/tests/unit/test_staleness_engine.py
+++ b/tests/unit/test_staleness_engine.py
@@ -2,14 +2,12 @@
 
 from __future__ import annotations
 
-import json
-from datetime import datetime, timedelta, timezone
+from datetime import UTC, datetime, timedelta
 from pathlib import Path
-from unittest.mock import MagicMock, patch, AsyncMock
+from unittest.mock import AsyncMock, MagicMock, patch
 
 import pytest
 
-
 # ---------------------------------------------------------------------------
 # Helpers
 # ---------------------------------------------------------------------------
@@ -41,7 +39,7 @@ def _make_pr(number=1, title="Test PR", days_old=10, html_url="http://example.co
     pr.number = number
     pr.title = title
     pr.html_url = html_url
-    pr.created_at = datetime.now(timezone.utc) - timedelta(days=days_old)
+    pr.created_at = datetime.now(UTC) - timedelta(days=days_old)
     return pr
 
 
diff --git a/tests/unit/test_triage_agent.py b/tests/unit/test_triage_agent.py
index 0745683..023f63b 100644
--- a/tests/unit/test_triage_agent.py
+++ b/tests/unit/test_triage_agent.py
@@ -4,9 +4,7 @@
 
 import asyncio
 import json
-import tempfile
-from pathlib import Path
-from unittest.mock import AsyncMock, MagicMock, patch
+from unittest.mock import AsyncMock, patch
 
 
 def run(coro):
@@ -94,9 +92,10 @@ def test_returns_empty_when_file_missing(self, tmp_path, monkeypatch):
         assert result == []
 
     def test_returns_records_within_window(self, tmp_path, monkeypatch):
-        import agents.triage_agent as mod
         from datetime import datetime, timedelta
 
+        import agents.triage_agent as mod
+
         monkeypatch.setattr(mod, "project_root", tmp_path)
         costs_path = tmp_path / ".llm_costs.jsonl"
         recent = (datetime.now() - timedelta(days=1)).isoformat()
@@ -138,9 +137,10 @@ def setup_method(self):
         self.agent = _make_agent()
 
     def test_no_slack_url_prints_and_returns(self, tmp_path, monkeypatch, capsys):
-        import agents.triage_agent as mod
         from datetime import datetime, timedelta
 
+        import agents.triage_agent as mod
+
         monkeypatch.setattr(mod, "project_root", tmp_path)
         monkeypatch.delenv("SLACK_WEBHOOK_URL", raising=False)
 
@@ -174,9 +174,10 @@ def test_empty_costs_returns_zero(self, tmp_path, monkeypatch):
         assert result["records"] == 0
 
     def test_multiple_models_aggregated(self, tmp_path, monkeypatch):
-        import agents.triage_agent as mod
         from datetime import datetime, timedelta
 
+        import agents.triage_agent as mod
+
         monkeypatch.setattr(mod, "project_root", tmp_path)
         monkeypatch.delenv("SLACK_WEBHOOK_URL", raising=False)