diff --git a/scripts/perf_bottleneck_finder.py b/scripts/perf_bottleneck_finder.py
new file mode 100644
index 0000000..e40ad6a
--- /dev/null
+++ b/scripts/perf_bottleneck_finder.py
@@ -0,0 +1,551 @@
+#!/usr/bin/env python3
+"""
+Performance Bottleneck Finder — Identify slow tests, builds, and CI steps.
+
+Analyzes:
+  1. Pytest output for slow tests
+  2. Build logs for slow steps
+  3. CI workflow durations
+  4. File system for large/slow artifacts
+
+Usage:
+    python3 scripts/perf_bottleneck_finder.py --repo /path/to/repo
+    python3 scripts/perf_bottleneck_finder.py --repo /path/to/repo --json
+    python3 scripts/perf_bottleneck_finder.py --repo /path/to/repo --report metrics/perf_report.md
+
+Weekly cron:
+    0 9 * * 1 cd /path/to/compounding-intelligence && python3 scripts/perf_bottleneck_finder.py --repo /path/to/target --report metrics/perf_report.md
+"""
+
+import argparse
+import json
+import os
+import re
+import subprocess
+import sys
+from collections import defaultdict
+from dataclasses import dataclass, field, asdict
+from datetime import datetime, timezone
+from pathlib import Path
+from typing import Any, Dict, List, Optional, Tuple
+
+
+# ── Configuration ──────────────────────────────────────────────────
+
+SLOW_TEST_THRESHOLD_S = 2.0      # Tests slower than this are flagged
+SLOW_BUILD_STEP_THRESHOLD_S = 10.0
+TOP_N_BOTTLENECKS = 10           # Report top N bottlenecks
+PYTEST_DURATIONS_COUNT = 20      # Number of slow tests to collect
+LOG_EXTENSIONS = {".log", ".txt"}
+
+
+@dataclass
+class Bottleneck:
+    """A single performance bottleneck."""
+    category: str          # "test", "build", "ci", "artifact", "import"
+    name: str              # What's slow
+    duration_s: float      # How long it takes
+    severity: str          # "critical", "warning", "info"
+    recommendation: str    # How to fix
+    file_path: Optional[str] = None
+    line_number: Optional[int] = None
+
+
+@dataclass
+class PerfReport:
+    """Full performance report."""
+    timestamp: str
+    repo_path: str
+    bottlenecks: List[Bottleneck] = field(default_factory=list)
+    summary: Dict[str, Any] = field(default_factory=dict)
+    test_stats: Dict[str, Any] = field(default_factory=dict)
+    build_stats: Dict[str, Any] = field(default_factory=dict)
+    ci_stats: Dict[str, Any] = field(default_factory=dict)
+
+    def to_dict(self) -> dict:
+        d = asdict(self)
+        return d
+
+
+# ── Test Analysis ──────────────────────────────────────────────────
+
+def find_slow_tests_pytest(repo_path: str) -> List[Bottleneck]:
+    """Run pytest --durations and parse slow tests."""
+    bottlenecks = []
+
+    # Try to run pytest with durations
+    try:
+        result = subprocess.run(
+            ["python3", "-m", "pytest", "--co", "-q", "--durations=0"],
+            cwd=repo_path, capture_output=True, text=True, timeout=30
+        )
+        # If tests exist, try to get durations from last run
+        durations_file = os.path.join(repo_path, ".pytest_cache", "v", "cache", "durations")
+        if os.path.exists(durations_file):
+            with open(durations_file) as f:
+                for line in f:
+                    parts = line.strip().split()
+                    if len(parts) >= 2:
+                        try:
+                            duration = float(parts[0])
+                            test_name = " ".join(parts[1:])
+                            if duration > SLOW_TEST_THRESHOLD_S:
+                                severity = "critical" if duration > 10 else "warning"
+                                bottlenecks.append(Bottleneck(
+                                    category="test",
+                                    name=test_name,
+                                    duration_s=duration,
+                                    severity=severity,
+                                    recommendation=f"Test takes {duration:.1f}s. Consider mocking slow I/O, using fixtures, or marking with @pytest.mark.slow."
+                                ))
+                        except ValueError:
+                            continue
+    except (subprocess.TimeoutExpired, FileNotFoundError):
+        pass
+
+    return bottlenecks
+
+
+def find_slow_tests_by_scan(repo_path: str) -> List[Bottleneck]:
+    """Scan test files for patterns that indicate slow tests."""
+    bottlenecks = []
+    test_patterns = [
+        (r"time\.sleep\((\d+(?:\.\d+)?)\)", "Contains time.sleep() — consider using mock or async wait"),
+        (r"subprocess\.run\(.*timeout=(\d+)", "Subprocess with timeout — may block test"),
+        (r"requests\.(get|post|put|delete)\(", "Real HTTP call — mock with responses or httpretty"),
+        (r"open\([^)]*['"]w['"]", "File I/O in test — use tmp_path fixture"),
+    ]
+
+    for root, dirs, files in os.walk(repo_path):
+        # Skip hidden and cache dirs
+        dirs[:] = [d for d in dirs if not d.startswith(('.', '__pycache__', 'node_modules', '.git'))]
+
+        for fname in files:
+            if not (fname.startswith("test_") or fname.endswith("_test.py")):
+                continue
+            if not fname.endswith(".py"):
+                continue
+
+            fpath = os.path.join(root, fname)
+            rel_path = os.path.relpath(fpath, repo_path)
+
+            try:
+                with open(fpath) as f:
+                    lines = f.readlines()
+            except (PermissionError, UnicodeDecodeError):
+                continue
+
+            for i, line in enumerate(lines):
+                for pattern, recommendation in test_patterns:
+                    match = re.search(pattern, line)
+                    if match:
+                        duration = 1.0  # Default estimate
+                        if "sleep" in pattern:
+                            try:
+                                duration = float(match.group(1))
+                            except (ValueError, IndexError):
+                                duration = 1.0
+                        elif "timeout" in pattern:
+                            try:
+                                duration = float(match.group(1))
+                            except (ValueError, IndexError):
+                                duration = 10.0
+                        else:
+                            duration = 2.0  # Estimated
+
+                        bottlenecks.append(Bottleneck(
+                            category="test",
+                            name=f"{rel_path}:{i+1}",
+                            duration_s=duration,
+                            severity="warning" if duration < 5 else "critical",
+                            recommendation=recommendation,
+                            file_path=rel_path,
+                            line_number=i + 1
+                        ))
+
+    return bottlenecks
+
+
+# ── Build Analysis ─────────────────────────────────────────────────
+
+def analyze_build_artifacts(repo_path: str) -> List[Bottleneck]:
+    """Find large build artifacts that slow down builds."""
+    bottlenecks = []
+    large_dirs = {
+        "node_modules": "Consider using npm ci --production or yarn --production",
+        "__pycache__": "Consider .gitignore and cleaning before builds",
+        ".tox": "Consider caching tox environments",
+        ".pytest_cache": "Consider cleaning between CI runs",
+        "dist": "Check if dist/ artifacts are being rebuilt unnecessarily",
+        "build": "Check if build/ artifacts are being rebuilt unnecessarily",
+        ".next": "Next.js cache — consider incremental builds",
+        "venv": "Virtual env in repo — move outside or use Docker",
+    }
+
+    for dirname, recommendation in large_dirs.items():
+        dirpath = os.path.join(repo_path, dirname)
+        if os.path.isdir(dirpath):
+            total_size = 0
+            file_count = 0
+            for root, dirs, files in os.walk(dirpath):
+                for f in files:
+                    try:
+                        fpath = os.path.join(root, f)
+                        total_size += os.path.getsize(fpath)
+                        file_count += 1
+                    except OSError:
+                        pass
+
+            if total_size > 10 * 1024 * 1024:  # > 10MB
+                size_mb = total_size / (1024 * 1024)
+                bottlenecks.append(Bottleneck(
+                    category="build",
+                    name=f"{dirname}/ ({size_mb:.1f}MB, {file_count} files)",
+                    duration_s=size_mb * 0.5,  # Rough estimate
+                    severity="critical" if size_mb > 100 else "warning",
+                    recommendation=recommendation
+                ))
+
+    return bottlenecks
+
+
+def analyze_makefile_targets(repo_path: str) -> List[Bottleneck]:
+    """Analyze Makefile for potentially slow targets."""
+    bottlenecks = []
+    makefiles = []
+
+    for root, dirs, files in os.walk(repo_path):
+        dirs[:] = [d for d in dirs if not d.startswith(('.', '__pycache__'))]
+        for f in files:
+            if f in ("Makefile", "makefile", "GNUmakefile"):
+                makefiles.append(os.path.join(root, f))
+
+    slow_patterns = [
+        (r"pip install", "pip install without --no-deps or constraints"),
+        (r"npm install(?!.*--production)", "npm install without --production flag"),
+        (r"docker build", "Docker build — consider multi-stage and layer caching"),
+        (r"pytest(?!.*-x|--maxfail)", "pytest without early exit on failure"),
+        (r"mypy|mypy --strict", "Type checking — consider incremental mode"),
+    ]
+
+    for mfile in makefiles:
+        rel_path = os.path.relpath(mfile, repo_path)
+        try:
+            with open(mfile) as f:
+                content = f.read()
+        except (PermissionError, UnicodeDecodeError):
+            continue
+
+        for pattern, recommendation in slow_patterns:
+            if re.search(pattern, content):
+                bottlenecks.append(Bottleneck(
+                    category="build",
+                    name=f"{rel_path}: {pattern}",
+                    duration_s=5.0,
+                    severity="info",
+                    recommendation=recommendation,
+                    file_path=rel_path
+                ))
+
+    return bottlenecks
+
+
+# ── CI Analysis ────────────────────────────────────────────────────
+
+def analyze_github_actions(repo_path: str) -> List[Bottleneck]:
+    """Analyze GitHub Actions workflow files for inefficiencies."""
+    bottlenecks = []
+    workflow_dir = os.path.join(repo_path, ".github", "workflows")
+
+    if not os.path.isdir(workflow_dir):
+        return bottlenecks
+
+    slow_patterns = [
+        (r"runs-on:\s*ubuntu-latest", 0, "Consider caching dependencies between runs"),
+        (r"npm install", 2, "Use npm ci instead of npm install for reproducible builds"),
+        (r"pip install(?!.*--cache-dir)", 2, "Add --cache-dir or use pip cache action"),
+        (r"docker build(?!.*--cache-from)", 5, "Use Docker layer caching"),
+        (r"python -m pytest(?!.*-n|--numprocesses)", 3, "Consider pytest-xdist for parallel test execution"),
+    ]
+
+    for fname in os.listdir(workflow_dir):
+        if not fname.endswith(('.yml', '.yaml')):
+            continue
+
+        fpath = os.path.join(workflow_dir, fname)
+        try:
+            with open(fpath) as f:
+                content = f.read()
+        except (PermissionError, UnicodeDecodeError):
+            continue
+
+        for pattern, est_savings, recommendation in slow_patterns:
+            if re.search(pattern, content):
+                bottlenecks.append(Bottleneck(
+                    category="ci",
+                    name=f"{fname}: {pattern}",
+                    duration_s=est_savings,
+                    severity="info",
+                    recommendation=recommendation,
+                    file_path=f".github/workflows/{fname}"
+                ))
+
+    return bottlenecks
+
+
+def analyze_gitea_ci(repo_path: str) -> List[Bottleneck]:
+    """Analyze Gitea/Drone CI config files."""
+    bottlenecks = []
+    ci_files = [".gitea/workflows", ".drone.yml", ".woodpecker.yml"]
+
+    for ci_path in ci_files:
+        full_path = os.path.join(repo_path, ci_path)
+        if os.path.isfile(full_path):
+            try:
+                with open(full_path) as f:
+                    content = f.read()
+            except (PermissionError, UnicodeDecodeError):
+                continue
+
+            if "pip install" in content and "--cache-dir" not in content:
+                bottlenecks.append(Bottleneck(
+                    category="ci",
+                    name=f"{ci_path}: pip without cache",
+                    duration_s=5.0,
+                    severity="warning",
+                    recommendation="Add --cache-dir or mount pip cache volume",
+                    file_path=ci_path
+                ))
+
+        elif os.path.isdir(full_path):
+            for fname in os.listdir(full_path):
+                if not fname.endswith(('.yml', '.yaml')):
+                    continue
+                fpath = os.path.join(full_path, fname)
+                try:
+                    with open(fpath) as f:
+                        content = f.read()
+                except (PermissionError, UnicodeDecodeError):
+                    continue
+
+                if "pip install" in content and "--cache-dir" not in content:
+                    bottlenecks.append(Bottleneck(
+                        category="ci",
+                        name=f"{ci_path}/{fname}: pip without cache",
+                        duration_s=5.0,
+                        severity="warning",
+                        recommendation="Add --cache-dir or mount pip cache volume",
+                        file_path=f"{ci_path}/{fname}"
+                    ))
+
+    return bottlenecks
+
+
+# ── Import Analysis ────────────────────────────────────────────────
+
+def find_slow_imports(repo_path: str) -> List[Bottleneck]:
+    """Find Python files with heavy import chains."""
+    bottlenecks = []
+    heavy_imports = {
+        "pandas": 0.5,
+        "numpy": 0.3,
+        "torch": 2.0,
+        "tensorflow": 3.0,
+        "scipy": 0.5,
+        "matplotlib": 0.8,
+        "sklearn": 0.5,
+        "transformers": 1.5,
+    }
+
+    for root, dirs, files in os.walk(repo_path):
+        dirs[:] = [d for d in dirs if not d.startswith(('.', '__pycache__', 'node_modules'))]
+        for fname in files:
+            if not fname.endswith(".py"):
+                continue
+
+            fpath = os.path.join(root, fname)
+            rel_path = os.path.relpath(fpath, repo_path)
+
+            try:
+                with open(fpath) as f:
+                    lines = f.readlines()
+            except (PermissionError, UnicodeDecodeError):
+                continue
+
+            for i, line in enumerate(lines):
+                stripped = line.strip()
+                if stripped.startswith("import ") or stripped.startswith("from "):
+                    for heavy, est_time in heavy_imports.items():
+                        if heavy in stripped:
+                            bottlenecks.append(Bottleneck(
+                                category="import",
+                                name=f"{rel_path}:{i+1}: import {heavy}",
+                                duration_s=est_time,
+                                severity="info" if est_time < 1.0 else "warning",
+                                recommendation=f"Heavy import ({heavy} ~{est_time}s). Consider lazy import or conditional import.",
+                                file_path=rel_path,
+                                line_number=i + 1
+                            ))
+
+    return bottlenecks
+
+
+# ── Report Generation ──────────────────────────────────────────────
+
+def severity_sort_key(b: Bottleneck) -> Tuple[int, float]:
+    """Sort by severity then duration."""
+    sev_order = {"critical": 0, "warning": 1, "info": 2}
+    return (sev_order.get(b.severity, 3), -b.duration_s)
+
+
+def generate_report(repo_path: str) -> PerfReport:
+    """Run all analyses and generate a performance report."""
+    report = PerfReport(
+        timestamp=datetime.now(timezone.utc).isoformat(),
+        repo_path=os.path.abspath(repo_path)
+    )
+
+    # Collect all bottlenecks
+    all_bottlenecks = []
+
+    print("Scanning for slow tests (pytest cache)...")
+    all_bottlenecks.extend(find_slow_tests_pytest(repo_path))
+
+    print("Scanning for slow test patterns...")
+    all_bottlenecks.extend(find_slow_tests_by_scan(repo_path))
+
+    print("Analyzing build artifacts...")
+    all_bottlenecks.extend(analyze_build_artifacts(repo_path))
+
+    print("Analyzing Makefiles...")
+    all_bottlenecks.extend(analyze_makefile_targets(repo_path))
+
+    print("Analyzing CI workflows...")
+    all_bottlenecks.extend(analyze_github_actions(repo_path))
+    all_bottlenecks.extend(analyze_gitea_ci(repo_path))
+
+    print("Scanning for heavy imports...")
+    all_bottlenecks.extend(find_slow_imports(repo_path))
+
+    # Sort by severity and duration
+    all_bottlenecks.sort(key=severity_sort_key)
+    report.bottlenecks = all_bottlenecks[:TOP_N_BOTTLENECKS * 2]  # Keep more for stats
+
+    # Compute summary
+    by_category = defaultdict(list)
+    for b in all_bottlenecks:
+        by_category[b.category].append(b)
+
+    report.summary = {
+        "total_bottlenecks": len(all_bottlenecks),
+        "critical": sum(1 for b in all_bottlenecks if b.severity == "critical"),
+        "warning": sum(1 for b in all_bottlenecks if b.severity == "warning"),
+        "info": sum(1 for b in all_bottlenecks if b.severity == "info"),
+        "estimated_total_slowdown_s": sum(b.duration_s for b in all_bottlenecks),
+        "by_category": {cat: len(items) for cat, items in by_category.items()},
+    }
+
+    report.test_stats = {
+        "slow_tests": len(by_category.get("test", [])),
+        "total_estimated_s": sum(b.duration_s for b in by_category.get("test", [])),
+    }
+
+    report.build_stats = {
+        "build_issues": len(by_category.get("build", [])),
+        "total_estimated_s": sum(b.duration_s for b in by_category.get("build", [])),
+    }
+
+    report.ci_stats = {
+        "ci_issues": len(by_category.get("ci", [])),
+        "total_estimated_s": sum(b.duration_s for b in by_category.get("ci", [])),
+    }
+
+    return report
+
+
+def format_markdown(report: PerfReport) -> str:
+    """Format report as markdown."""
+    lines = []
+    lines.append(f"# Performance Bottleneck Report")
+    lines.append(f"")
+    lines.append(f"Generated: {report.timestamp}")
+    lines.append(f"Repository: {report.repo_path}")
+    lines.append(f"")
+
+    # Summary
+    s = report.summary
+    lines.append(f"## Summary")
+    lines.append(f"")
+    lines.append(f"- **Total bottlenecks:** {s['total_bottlenecks']}")
+    lines.append(f"- **Critical:** {s['critical']} | **Warning:** {s['warning']} | **Info:** {s['info']}")
+    lines.append(f"- **Estimated total slowdown:** {s['estimated_total_slowdown_s']:.1f}s")
+    lines.append(f"- **By category:** {', '.join(f'{k}: {v}' for k, v in s['by_category'].items())}")
+    lines.append(f"")
+
+    # Top bottlenecks
+    lines.append(f"## Top {min(TOP_N_BOTTLENECKS, len(report.bottlenecks))} Bottlenecks")
+    lines.append(f"")
+
+    for i, b in enumerate(report.bottlenecks[:TOP_N_BOTTLENECKS], 1):
+        icon = {"critical": "🔴", "warning": "🟡", "info": "🔵"}.get(b.severity, "⚪")
+        loc = f" ({b.file_path}:{b.line_number})" if b.file_path else ""
+        lines.append(f"{i}. {icon} **{b.category}** — {b.name}{loc}")
+        lines.append(f"   - Duration: ~{b.duration_s:.1f}s | Severity: {b.severity}")
+        lines.append(f"   - Fix: {b.recommendation}")
+        lines.append(f"")
+
+    # Category breakdowns
+    for cat in ["test", "build", "ci", "import"]:
+        items = [b for b in report.bottlenecks if b.category == cat]
+        if items:
+            lines.append(f"## {cat.title()} Bottlenecks")
+            lines.append(f"")
+            for b in items:
+                icon = {"critical": "🔴", "warning": "🟡", "info": "🔵"}.get(b.severity, "⚪")
+                loc = f" ({b.file_path}:{b.line_number})" if b.file_path else ""
+                lines.append(f"- {icon} {b.name}{loc} — ~{b.duration_s:.1f}s — {b.recommendation}")
+            lines.append(f"")
+
+    return "
+".join(lines)
+
+
+# ── Main ───────────────────────────────────────────────────────────
+
+def main():
+    parser = argparse.ArgumentParser(description="Performance Bottleneck Finder")
+    parser.add_argument("--repo", default=".", help="Path to repository to analyze")
+    parser.add_argument("--json", action="store_true", help="Output as JSON")
+    parser.add_argument("--report", help="Write markdown report to file")
+    parser.add_argument("--threshold", type=float, default=SLOW_TEST_THRESHOLD_S,
+                        help="Slow test threshold in seconds")
+    args = parser.parse_args()
+
+    global SLOW_TEST_THRESHOLD_S
+    SLOW_TEST_THRESHOLD_S = args.threshold
+
+    if not os.path.isdir(args.repo):
+        print(f"Error: {args.repo} is not a directory", file=sys.stderr)
+        sys.exit(1)
+
+    report = generate_report(args.repo)
+
+    if args.json:
+        print(json.dumps(report.to_dict(), indent=2))
+    else:
+        md = format_markdown(report)
+        if args.report:
+            os.makedirs(os.path.dirname(args.report) or ".", exist_ok=True)
+            with open(args.report, "w") as f:
+                f.write(md)
+            print(f"Report written to {args.report}")
+        else:
+            print(md)
+
+    # Exit code: 1 if critical bottlenecks found
+    if report.summary.get("critical", 0) > 0:
+        sys.exit(1)
+
+
+if __name__ == "__main__":
+    main()
diff --git a/tests/test_perf_bottleneck_finder.py b/tests/test_perf_bottleneck_finder.py
new file mode 100644
index 0000000..02f2ba3
--- /dev/null
+++ b/tests/test_perf_bottleneck_finder.py
@@ -0,0 +1,319 @@
+#!/usr/bin/env python3
+"""
+Tests for Performance Bottleneck Finder.
+"""
+
+import json
+import os
+import tempfile
+import textwrap
+from pathlib import Path
+
+import pytest
+
+# Add scripts to path
+import sys
+sys.path.insert(0, os.path.join(os.path.dirname(__file__), "..", "scripts"))
+
+from perf_bottleneck_finder import (
+    Bottleneck,
+    PerfReport,
+    find_slow_tests_by_scan,
+    analyze_build_artifacts,
+    analyze_makefile_targets,
+    find_slow_imports,
+    generate_report,
+    format_markdown,
+    severity_sort_key,
+)
+
+
+class TestBottleneck:
+    """Test Bottleneck dataclass."""
+
+    def test_creation(self):
+        b = Bottleneck(
+            category="test",
+            name="test_foo",
+            duration_s=5.0,
+            severity="warning",
+            recommendation="Mock it"
+        )
+        assert b.category == "test"
+        assert b.name == "test_foo"
+        assert b.duration_s == 5.0
+        assert b.severity == "warning"
+        assert b.recommendation == "Mock it"
+        assert b.file_path is None
+        assert b.line_number is None
+
+    def test_with_location(self):
+        b = Bottleneck(
+            category="test",
+            name="test_bar",
+            duration_s=2.0,
+            severity="info",
+            recommendation="Consider",
+            file_path="tests/test_bar.py",
+            line_number=42
+        )
+        assert b.file_path == "tests/test_bar.py"
+        assert b.line_number == 42
+
+    def test_to_dict(self):
+        b = Bottleneck("test", "x", 1.0, "info", "y")
+        d = b.__dict__
+        assert "category" in d
+        assert "duration_s" in d
+
+
+class TestPerfReport:
+    """Test PerfReport dataclass."""
+
+    def test_creation(self):
+        report = PerfReport(
+            timestamp="2026-01-01T00:00:00Z",
+            repo_path="/tmp/repo"
+        )
+        assert report.timestamp == "2026-01-01T00:00:00Z"
+        assert report.bottlenecks == []
+        assert report.summary == {}
+
+    def test_to_dict(self):
+        report = PerfReport(
+            timestamp="2026-01-01T00:00:00Z",
+            repo_path="/tmp/repo",
+            bottlenecks=[Bottleneck("test", "x", 1.0, "info", "y")]
+        )
+        d = report.to_dict()
+        assert "bottlenecks" in d
+        assert len(d["bottlenecks"]) == 1
+
+
+class TestSeveritySort:
+    """Test severity sorting."""
+
+    def test_critical_first(self):
+        items = [
+            Bottleneck("test", "a", 1.0, "info", ""),
+            Bottleneck("test", "b", 0.5, "critical", ""),
+            Bottleneck("test", "c", 2.0, "warning", ""),
+        ]
+        items.sort(key=severity_sort_key)
+        assert items[0].severity == "critical"
+        assert items[1].severity == "warning"
+        assert items[2].severity == "info"
+
+    def test_duration_within_severity(self):
+        items = [
+            Bottleneck("test", "slow", 10.0, "warning", ""),
+            Bottleneck("test", "fast", 1.0, "warning", ""),
+        ]
+        items.sort(key=severity_sort_key)
+        assert items[0].name == "slow"  # Higher duration first within same severity
+
+
+class TestSlowTestScan:
+    """Test slow test pattern scanning."""
+
+    def test_finds_sleep(self, tmp_path):
+        test_file = tmp_path / "test_sleepy.py"
+        test_file.write_text(textwrap.dedent('''
+            import time
+
+            def test_slow():
+                time.sleep(5)
+                assert True
+        '''))
+
+        bottlenecks = find_slow_tests_by_scan(str(tmp_path))
+        assert len(bottlenecks) >= 1
+        assert any("sleep" in b.recommendation.lower() for b in bottlenecks)
+
+    def test_finds_http_calls(self, tmp_path):
+        test_file = tmp_path / "test_http.py"
+        test_file.write_text(textwrap.dedent('''
+            import requests
+
+            def test_api():
+                resp = requests.get("https://example.com")
+                assert resp.status_code == 200
+        '''))
+
+        bottlenecks = find_slow_tests_by_scan(str(tmp_path))
+        assert len(bottlenecks) >= 1
+        assert any("HTTP" in b.recommendation or "mock" in b.recommendation.lower() for b in bottlenecks)
+
+    def test_skips_non_test_files(self, tmp_path):
+        src_file = tmp_path / "main.py"
+        src_file.write_text("import time\ntime.sleep(10)\n")
+
+        bottlenecks = find_slow_tests_by_scan(str(tmp_path))
+        assert len(bottlenecks) == 0
+
+    def test_handles_missing_dir(self):
+        bottlenecks = find_slow_tests_by_scan("/nonexistent/path")
+        assert bottlenecks == []
+
+    def test_file_path_populated(self, tmp_path):
+        test_file = tmp_path / "test_example.py"
+        test_file.write_text("import time\n\ndef test_it():\n    time.sleep(2)\n")
+
+        bottlenecks = find_slow_tests_by_scan(str(tmp_path))
+        assert len(bottlenecks) >= 1
+        assert bottlenecks[0].file_path is not None
+        assert bottlenecks[0].line_number is not None
+
+
+class TestBuildArtifacts:
+    """Test build artifact analysis."""
+
+    def test_finds_large_node_modules(self, tmp_path):
+        nm = tmp_path / "node_modules"
+        nm.mkdir()
+        # Create a file > 10MB
+        big_file = nm / "big.txt"
+        big_file.write_bytes(b"x" * (11 * 1024 * 1024))
+
+        bottlenecks = analyze_build_artifacts(str(tmp_path))
+        assert len(bottlenecks) >= 1
+        assert any("node_modules" in b.name for b in bottlenecks)
+
+    def test_ignores_small_dirs(self, tmp_path):
+        nm = tmp_path / "node_modules"
+        nm.mkdir()
+        small_file = nm / "small.txt"
+        small_file.write_bytes(b"x" * 100)
+
+        bottlenecks = analyze_build_artifacts(str(tmp_path))
+        assert not any("node_modules" in b.name for b in bottlenecks)
+
+    def test_finds_pycache(self, tmp_path):
+        cache = tmp_path / "__pycache__"
+        cache.mkdir()
+        big_file = cache / "big.pyc"
+        big_file.write_bytes(b"x" * (11 * 1024 * 1024))
+
+        bottlenecks = analyze_build_artifacts(str(tmp_path))
+        assert any("__pycache__" in b.name for b in bottlenecks)
+
+
+class TestMakefileAnalysis:
+    """Test Makefile analysis."""
+
+    def test_finds_pip_install(self, tmp_path):
+        makefile = tmp_path / "Makefile"
+        makefile.write_text(textwrap.dedent('''
+            install:
+                pip install -r requirements.txt
+
+            test:
+                pytest
+        '''))
+
+        bottlenecks = analyze_makefile_targets(str(tmp_path))
+        assert len(bottlenecks) >= 1
+
+    def test_no_makefile(self, tmp_path):
+        bottlenecks = analyze_makefile_targets(str(tmp_path))
+        assert bottlenecks == []
+
+
+class TestImportAnalysis:
+    """Test heavy import detection."""
+
+    def test_finds_pandas(self, tmp_path):
+        src = tmp_path / "analysis.py"
+        src.write_text("import pandas as pd\n")
+
+        bottlenecks = find_slow_imports(str(tmp_path))
+        assert len(bottlenecks) >= 1
+        assert any("pandas" in b.name for b in bottlenecks)
+
+    def test_finds_torch(self, tmp_path):
+        src = tmp_path / "model.py"
+        src.write_text("import torch\n")
+
+        bottlenecks = find_slow_imports(str(tmp_path))
+        assert any("torch" in b.name for b in bottlenecks)
+
+    def test_skips_light_imports(self, tmp_path):
+        src = tmp_path / "utils.py"
+        src.write_text("import json\nimport os\nimport sys\n")
+
+        bottlenecks = find_slow_imports(str(tmp_path))
+        assert len(bottlenecks) == 0
+
+
+class TestGenerateReport:
+    """Test full report generation."""
+
+    def test_empty_repo(self, tmp_path):
+        report = generate_report(str(tmp_path))
+        assert report.summary["total_bottlenecks"] >= 0
+        assert "critical" in report.summary
+        assert "warning" in report.summary
+
+    def test_with_findings(self, tmp_path):
+        # Create a test file with issues
+        test_file = tmp_path / "test_slow.py"
+        test_file.write_text(textwrap.dedent('''
+            import time
+            import requests
+
+            def test_sleepy():
+                time.sleep(3)
+
+            def test_http():
+                requests.get("https://example.com")
+        '''))
+
+        report = generate_report(str(tmp_path))
+        assert report.summary["total_bottlenecks"] >= 2
+        assert len(report.bottlenecks) > 0
+
+    def test_summary_categories(self, tmp_path):
+        report = generate_report(str(tmp_path))
+        assert "by_category" in report.summary
+
+
+class TestMarkdownReport:
+    """Test markdown output."""
+
+    def test_format(self):
+        report = PerfReport(
+            timestamp="2026-01-01T00:00:00Z",
+            repo_path="/tmp/repo",
+            bottlenecks=[
+                Bottleneck("test", "slow_test", 5.0, "critical", "Fix it")
+            ],
+            summary={
+                "total_bottlenecks": 1,
+                "critical": 1,
+                "warning": 0,
+                "info": 0,
+                "estimated_total_slowdown_s": 5.0,
+                "by_category": {"test": 1},
+            }
+        )
+        md = format_markdown(report)
+        assert "# Performance Bottleneck Report" in md
+        assert "slow_test" in md
+        assert "🔴" in md
+        assert "Fix it" in md
+
+    def test_empty_report(self):
+        report = PerfReport(
+            timestamp="2026-01-01T00:00:00Z",
+            repo_path="/tmp/repo",
+            summary={
+                "total_bottlenecks": 0,
+                "critical": 0,
+                "warning": 0,
+                "info": 0,
+                "estimated_total_slowdown_s": 0,
+                "by_category": {},
+            }
+        )
+        md = format_markdown(report)
+        assert "Total bottlenecks:** 0" in md