test: config drift detector (#686)

28 tests covering:
- YAML loading (valid, empty, invalid, non-dict)
- Nested flattening (dot paths, lists, deep nesting)
- Config diffing (changed, missing, extra, ignored keys, secrets)
- Sync patch generation (changed, missing, non-destructive)
- Markdown and report formatting

Closes #686

scripts/config_drift_detector.py

@@ -0,0 +1,494 @@
+#!/usr/bin/env python3
+"""
+Config Drift Detection — Timmy Foundation Fleet
+
+Collects hermes config from all fleet nodes via SSH, diffs against
+the canonical timmy-config, and reports drift.
+
+Usage:
+    # Full drift report
+    python3 scripts/config_drift_detector.py report
+
+    # JSON output
+    python3 scripts/config_drift_detector.py report --json
+
+    # Check a single node
+    python3 scripts/config_drift_detector.py check allegro
+
+    # Auto-sync a node (dry-run by default)
+    python3 scripts/config_drift_detector.py sync allegro
+    python3 scripts/config_drift_detector.py sync allegro --apply
+
+    # Sync all drifted nodes
+    python3 scripts/config_drift_detector.py sync-all
+"""
+
+import argparse
+import copy
+import json
+import os
+import subprocess
+import sys
+from datetime import datetime, timezone
+from pathlib import Path
+from typing import Any, Dict, List, Optional, Tuple
+
+import yaml
+
+# ── Fleet Definition ─────────────────────────────────────────────────────────
+
+SCRIPT_DIR = Path(__file__).resolve().parent
+ROOT_DIR = SCRIPT_DIR.parent
+CANONICAL_CONFIG = ROOT_DIR / "config.yaml"
+SYNC_LOG = ROOT_DIR / "fleet" / "drift-sync-log.json"
+
+FLEET_NODES = {
+    "timmy": {
+        "host": "localhost",
+        "ssh_user": None,
+        "hermes_home": os.path.expanduser("~/.hermes"),
+        "machine_type": "mac",
+    },
+    "allegro": {
+        "host": "167.99.126.228",
+        "ssh_user": "root",
+        "hermes_home": "/root/.hermes",
+        "machine_type": "vps",
+    },
+    "bezalel": {
+        "host": "159.203.146.185",
+        "ssh_user": "root",
+        "hermes_home": "/root/.hermes",
+        "machine_type": "vps",
+    },
+    "ezra": {
+        "host": "143.198.27.163",
+        "ssh_user": "root",
+        "hermes_home": "/root/.hermes",
+        "machine_type": "vps",
+    },
+}
+
+
+# ── Config Loading ───────────────────────────────────────────────────────────
+
+def load_yaml(text: str) -> dict:
+    """Parse YAML text, return empty dict on failure."""
+    try:
+        data = yaml.safe_load(text)
+        return data if isinstance(data, dict) else {}
+    except Exception:
+        return {}
+
+
+def load_canonical(path: Path = CANONICAL_CONFIG) -> dict:
+    """Load the canonical timmy-config."""
+    if path.exists():
+        with open(path, encoding="utf-8") as f:
+            return load_yaml(f.read())
+    return {}
+
+
+# ── Remote Config Collection ─────────────────────────────────────────────────
+
+def ssh_fetch_config(node_name: str, node_spec: dict) -> Optional[str]:
+    """Fetch config.yaml from a remote node via SSH."""
+    host = node_spec["host"]
+    user = node_spec.get("ssh_user")
+    hermes_home = node_spec["hermes_home"]
+    config_path = f"{hermes_home}/config.yaml"
+
+    if host == "localhost":
+        # Local read
+        try:
+            with open(config_path, encoding="utf-8") as f:
+                return f.read()
+        except FileNotFoundError:
+            return None
+        except Exception:
+            return None
+
+    # Remote SSH read
+    target = f"{user}@{host}" if user else host
+    try:
+        result = subprocess.run(
+            ["ssh", "-o", "ConnectTimeout=10", "-o", "StrictHostKeyChecking=no",
+             target, "cat", config_path],
+            capture_output=True, text=True, timeout=20
+        )
+        if result.returncode == 0:
+            return result.stdout
+        return None
+    except (subprocess.TimeoutExpired, Exception):
+        return None
+
+
+def collect_all_configs() -> Dict[str, Optional[dict]]:
+    """Collect configs from all fleet nodes."""
+    configs = {}
+    for name, spec in FLEET_NODES.items():
+        raw = ssh_fetch_config(name, spec)
+        configs[name] = load_yaml(raw) if raw else None
+    return configs
+
+
+# ── Diff Engine ──────────────────────────────────────────────────────────────
+
+def _flatten(d: dict, prefix: str = "") -> Dict[str, Any]:
+    """Flatten nested dict into dot-separated keys."""
+    items = {}
+    for k, v in d.items():
+        key = f"{prefix}.{k}" if prefix else str(k)
+        if isinstance(v, dict):
+            items.update(_flatten(v, key))
+        elif isinstance(v, list):
+            items[key] = json.dumps(v, sort_keys=True)
+        else:
+            items[key] = v
+    return items
+
+
+def diff_configs(canonical: dict, remote: dict,
+                 ignored_keys: Optional[List[str]] = None) -> List[Dict[str, Any]]:
+    """
+    Diff two config dicts. Returns list of drift entries.
+
+    Each entry: {key, canonical_value, remote_value, drift_type}
+    drift_type: "changed" | "missing_remote" | "extra_remote"
+    """
+    ignored = set(ignored_keys or [])
+    # Ignore keys that are inherently node-specific
+    ignored.update({
+        "terminal.cwd",  # varies per session
+        "display.skin",  # cosmetic
+    })
+
+    flat_canon = _flatten(canonical)
+    flat_remote = _flatten(remote)
+    drifts = []
+
+    all_keys = sorted(set(flat_canon.keys()) | set(flat_remote.keys()))
+
+    for key in all_keys:
+        if key in ignored:
+            continue
+        # Ignore keys ending with .api_key or .token (secrets, not drift)
+        if any(key.endswith(s) for s in (".api_key", ".token", ".api_token")):
+            continue
+
+        canon_val = flat_canon.get(key)
+        remote_val = flat_remote.get(key)
+
+        if canon_val is None and remote_val is not None:
+            drifts.append({
+                "key": key,
+                "canonical_value": None,
+                "remote_value": remote_val,
+                "drift_type": "extra_remote",
+            })
+        elif canon_val is not None and remote_val is None:
+            drifts.append({
+                "key": key,
+                "canonical_value": canon_val,
+                "remote_value": None,
+                "drift_type": "missing_remote",
+            })
+        elif canon_val != remote_val:
+            drifts.append({
+                "key": key,
+                "canonical_value": canon_val,
+                "remote_value": remote_val,
+                "drift_type": "changed",
+            })
+
+    return drifts
+
+
+# ── Report ───────────────────────────────────────────────────────────────────
+
+def check_node(node_name: str, canonical: dict) -> Dict[str, Any]:
+    """Check a single node for config drift."""
+    spec = FLEET_NODES.get(node_name)
+    if not spec:
+        return {"node": node_name, "error": f"Unknown node: {node_name}"}
+
+    raw = ssh_fetch_config(node_name, spec)
+    if raw is None:
+        return {
+            "node": node_name,
+            "host": spec["host"],
+            "reachable": False,
+            "drifts": [],
+            "drift_count": -1,
+            "error": "Could not fetch config",
+        }
+
+    remote_config = load_yaml(raw)
+    drifts = diff_configs(canonical, remote_config)
+
+    return {
+        "node": node_name,
+        "host": spec["host"],
+        "machine_type": spec["machine_type"],
+        "reachable": True,
+        "config_keys": len(_flatten(remote_config)),
+        "drifts": drifts,
+        "drift_count": len(drifts),
+        "has_drift": len(drifts) > 0,
+    }
+
+
+def report_all(canonical: dict) -> Dict[str, Any]:
+    """Full fleet drift report."""
+    now = datetime.now(timezone.utc).isoformat()
+    results = {}
+
+    for node_name in FLEET_NODES:
+        results[node_name] = check_node(node_name, canonical)
+
+    total_nodes = len(results)
+    reachable = sum(1 for r in results.values() if r.get("reachable", False))
+    drifted = sum(1 for r in results.values() if r.get("has_drift", False))
+    total_drifts = sum(r.get("drift_count", 0) for r in results.values())
+
+    return {
+        "timestamp": now,
+        "canonical_config": str(CANONICAL_CONFIG),
+        "total_nodes": total_nodes,
+        "reachable": reachable,
+        "unreachable": total_nodes - reachable,
+        "drifted_nodes": drifted,
+        "clean_nodes": reachable - drifted,
+        "total_drifts": total_drifts,
+        "nodes": results,
+    }
+
+
+# ── Formatters ───────────────────────────────────────────────────────────────
+
+def format_drift_markdown(drifts: List[Dict[str, Any]]) -> str:
+    """Format a list of drift entries as markdown table."""
+    if not drifts:
+        return "  (no drift — config matches canonical)\n"
+
+    lines = []
+    lines.append(f"  {'Key':<40} {'Canonical':<20} {'Remote':<20} {'Type'}")
+    lines.append(f"  {'─'*40} {'─'*20} {'─'*20} {'─'*12}")
+
+    for d in drifts[:30]:  # cap at 30 rows
+        key = d["key"][:39]
+        canon = str(d["canonical_value"] or "(absent)")[:19]
+        remote = str(d["remote_value"] or "(absent)")[:19]
+        dtype = d["drift_type"]
+        lines.append(f"  {key:<40} {canon:<20} {remote:<20} {dtype}")
+
+    if len(drifts) > 30:
+        lines.append(f"  ... and {len(drifts) - 30} more")
+
+    return "\n".join(lines) + "\n"
+
+
+def format_report(report: dict) -> str:
+    """Format full fleet report as terminal text."""
+    lines = [
+        "╔══════════════════════════════════════════════════════╗",
+        "║   🔍 CONFIG DRIFT DETECTION — TIMMY FOUNDATION       ║",
+        "╚══════════════════════════════════════════════════════╝",
+        "",
+        f"Timestamp: {report['timestamp'][:19]}Z",
+        f"Canonical: {report['canonical_config']}",
+        "",
+        f"Nodes: {report['total_nodes']} total, {report['reachable']} reachable, "
+        f"{report['unreachable']} unreachable",
+        f"Drift: {report['drifted_nodes']} drifted, {report['clean_nodes']} clean, "
+        f"{report['total_drifts']} total key differences",
+        "",
+    ]
+
+    for node_name, node in report["nodes"].items():
+        status = "🟢" if node.get("reachable") else "⚫"
+        drift_icon = "🔴" if node.get("has_drift") else "✅"
+        lines.append(f"── {node_name} ({node.get('host', '?')}) {status} {drift_icon} ──")
+
+        if not node.get("reachable"):
+            lines.append(f"  UNREACHABLE: {node.get('error', 'unknown')}")
+            lines.append("")
+            continue
+
+        lines.append(f"  Type: {node.get('machine_type', '?')}, "
+                     f"Keys: {node.get('config_keys', 0)}, "
+                     f"Drifts: {node.get('drift_count', 0)}")
+        lines.append(format_drift_markdown(node.get("drifts", [])))
+        lines.append("")
+
+    return "\n".join(lines)
+
+
+# ── Sync ─────────────────────────────────────────────────────────────────────
+
+def generate_sync_patch(canonical: dict, remote: dict) -> Dict[str, Any]:
+    """Generate the key-value pairs that need syncing."""
+    drifts = diff_configs(canonical, remote)
+    flat_canon = _flatten(canonical)
+
+    patch = {}
+    for d in drifts:
+        if d["drift_type"] == "changed":
+            patch[d["key"]] = d["canonical_value"]
+        elif d["drift_type"] == "missing_remote":
+            patch[d["key"]] = d["canonical_value"]
+        # Don't delete extra_remote keys — that's destructive
+
+    return patch
+
+
+def sync_node(node_name: str, canonical: dict, apply: bool = False) -> Dict[str, Any]:
+    """Sync a node's config to match canonical (dry-run or apply)."""
+    spec = FLEET_NODES.get(node_name)
+    if not spec:
+        return {"error": f"Unknown node: {node_name}"}
+
+    raw = ssh_fetch_config(node_name, spec)
+    if raw is None:
+        return {"error": "Could not fetch remote config"}
+
+    remote_config = load_yaml(raw)
+    patch = generate_sync_patch(canonical, remote_config)
+
+    result = {
+        "node": node_name,
+        "host": spec["host"],
+        "changes_needed": len(patch),
+        "dry_run": not apply,
+        "patch": patch,
+    }
+
+    if not apply or not patch:
+        return result
+
+    # Apply: write canonical config to remote
+    config_content = CANONICAL_CONFIG.read_text(encoding="utf-8") if CANONICAL_CONFIG.exists() else ""
+    config_path = f"{spec['hermes_home']}/config.yaml"
+
+    host = spec["host"]
+    if host == "localhost":
+        try:
+            os.makedirs(os.path.dirname(config_path), exist_ok=True)
+            with open(config_path, "w", encoding="utf-8") as f:
+                f.write(config_content)
+            result["applied"] = True
+        except Exception as e:
+            result["error"] = str(e)
+    else:
+        target = f"{spec['ssh_user']}@{host}" if spec.get("ssh_user") else host
+        try:
+            proc = subprocess.run(
+                ["ssh", "-o", "ConnectTimeout=10", target,
+                 f"cat > {config_path}"],
+                input=config_content, capture_output=True, text=True, timeout=20
+            )
+            result["applied"] = proc.returncode == 0
+            if proc.returncode != 0:
+                result["error"] = proc.stderr[:200]
+        except Exception as e:
+            result["error"] = str(e)
+
+    # Log the sync
+    if apply:
+        log_entry = {
+            "timestamp": datetime.now(timezone.utc).isoformat(),
+            "node": node_name,
+            "changes": len(patch),
+            "patch_keys": list(patch.keys()),
+        }
+        _append_sync_log(log_entry)
+
+    return result
+
+
+def _append_sync_log(entry: dict):
+    """Append to the sync log."""
+    log = []
+    if SYNC_LOG.exists():
+        try:
+            with open(SYNC_LOG) as f:
+                log = json.load(f)
+        except Exception:
+            pass
+    log.append(entry)
+    log = log[-100:]  # keep last 100
+    SYNC_LOG.parent.mkdir(parents=True, exist_ok=True)
+    with open(SYNC_LOG, "w") as f:
+        json.dump(log, f, indent=2)
+
+
+# ── CLI ──────────────────────────────────────────────────────────────────────
+
+def main():
+    parser = argparse.ArgumentParser(description="Config drift detection for the Timmy fleet")
+    sub = parser.add_subparsers(dest="command", required=True)
+
+    # report
+    rpt = sub.add_parser("report", help="Full fleet drift report")
+    rpt.add_argument("--json", action="store_true", help="JSON output")
+    rpt.add_argument("--canonical", type=str, default=None, help="Canonical config path")
+
+    # check
+    chk = sub.add_parser("check", help="Check a single node")
+    chk.add_argument("node", help="Node name (timmy, allegro, bezalel, ezra)")
+    chk.add_argument("--json", action="store_true", help="JSON output")
+
+    # sync
+    syn = sub.add_parser("sync", help="Sync a node to canonical")
+    syn.add_argument("node", help="Node name")
+    syn.add_argument("--apply", action="store_true", help="Actually apply changes")
+
+    # sync-all
+    sub.add_parser("sync-all", help="Sync all drifted nodes (dry-run)")
+
+    args = parser.parse_args()
+
+    canon_path = Path(args.canonical) if hasattr(args, "canonical") and args.canonical else CANONICAL_CONFIG
+    canonical = load_canonical(canon_path)
+
+    if args.command == "report":
+        report = report_all(canonical)
+        if args.json:
+            print(json.dumps(report, indent=2))
+        else:
+            print(format_report(report))
+
+    elif args.command == "check":
+        result = check_node(args.node, canonical)
+        if args.json:
+            print(json.dumps(result, indent=2))
+        else:
+            print(f"Node: {result['node']}")
+            print(f"Host: {result.get('host', '?')}")
+            print(f"Reachable: {result.get('reachable', False)}")
+            print(f"Drifts: {result.get('drift_count', 0)}")
+            if result.get("drifts"):
+                print(format_drift_markdown(result["drifts"]))
+
+    elif args.command == "sync":
+        result = sync_node(args.node, canonical, apply=args.apply)
+        print(json.dumps(result, indent=2))
+
+    elif args.command == "sync-all":
+        report = report_all(canonical)
+        synced = 0
+        for node_name, node in report["nodes"].items():
+            if node.get("has_drift") and node.get("reachable"):
+                result = sync_node(node_name, canonical, apply=False)
+                print(f"{node_name}: {result.get('changes_needed', 0)} changes needed (dry-run)")
+                synced += 1
+        if synced == 0:
+            print("No drifted nodes found. Fleet is clean.")
+        else:
+            print(f"\n{synced} node(s) need syncing. Run 'sync <node> --apply' to fix.")
+
+    return 0
+
+
+if __name__ == "__main__":
+    sys.exit(main())

tests/test_config_drift_detector.py

@@ -0,0 +1,228 @@
+"""Tests for config drift detection."""
+import json
+import sys
+from pathlib import Path
+
+import pytest
+
+SCRIPT_DIR = Path(__file__).resolve().parent.parent / "scripts"
+sys.path.insert(0, str(SCRIPT_DIR))
+
+from config_drift_detector import (
+    load_yaml,
+    _flatten,
+    diff_configs,
+    generate_sync_patch,
+    format_drift_markdown,
+    format_report,
+)
+
+
+# ── YAML Loading ─────────────────────────────────────────────────────────────
+
+class TestLoadYaml:
+    def test_valid_yaml(self):
+        result = load_yaml("model:\n  default: hermes\n  provider: nous")
+        assert result["model"]["default"] == "hermes"
+
+    def test_empty_string(self):
+        assert load_yaml("") == {}
+
+    def test_invalid_yaml(self):
+        assert load_yaml("{invalid yaml ][") == {}
+
+    def test_non_dict_root(self):
+        assert load_yaml("- item1\n- item2") == {}
+
+
+# ── Flatten ──────────────────────────────────────────────────────────────────
+
+class TestFlatten:
+    def test_flat_dict(self):
+        assert _flatten({"a": 1, "b": 2}) == {"a": 1, "b": 2}
+
+    def test_nested_dict(self):
+        result = _flatten({"model": {"default": "hermes", "provider": "nous"}})
+        assert result["model.default"] == "hermes"
+        assert result["model.provider"] == "nous"
+
+    def test_deeply_nested(self):
+        result = _flatten({"a": {"b": {"c": 42}}})
+        assert result["a.b.c"] == 42
+
+    def test_list_serialized_as_json(self):
+        result = _flatten({"toolsets": ["all", "terminal"]})
+        assert result["toolsets"] == '["all", "terminal"]'
+
+    def test_empty_dict(self):
+        assert _flatten({}) == {}
+
+
+# ── Diff Configs ─────────────────────────────────────────────────────────────
+
+class TestDiffConfigs:
+    def test_identical_configs(self):
+        cfg = {"model": {"default": "hermes"}, "agent": {"max_turns": 30}}
+        assert diff_configs(cfg, cfg) == []
+
+    def test_changed_value(self):
+        canon = {"model": {"default": "hermes"}}
+        remote = {"model": {"default": "gpt-4"}}
+        drifts = diff_configs(canon, remote)
+        assert len(drifts) == 1
+        assert drifts[0]["key"] == "model.default"
+        assert drifts[0]["drift_type"] == "changed"
+        assert drifts[0]["canonical_value"] == "hermes"
+        assert drifts[0]["remote_value"] == "gpt-4"
+
+    def test_missing_remote_key(self):
+        canon = {"model": {"default": "hermes"}, "agent": {"max_turns": 30}}
+        remote = {"model": {"default": "hermes"}}
+        drifts = diff_configs(canon, remote)
+        assert len(drifts) == 1
+        assert drifts[0]["key"] == "agent.max_turns"
+        assert drifts[0]["drift_type"] == "missing_remote"
+
+    def test_extra_remote_key(self):
+        canon = {"model": {"default": "hermes"}}
+        remote = {"model": {"default": "hermes"}, "extra": {"key": 1}}
+        drifts = diff_configs(canon, remote)
+        assert len(drifts) == 1
+        assert drifts[0]["drift_type"] == "extra_remote"
+
+    def test_ignored_keys(self):
+        canon = {"terminal": {"cwd": "/a"}, "model": {"default": "hermes"}}
+        remote = {"terminal": {"cwd": "/b"}, "model": {"default": "hermes"}}
+        # terminal.cwd is in the default ignore list
+        drifts = diff_configs(canon, remote)
+        assert len(drifts) == 0
+
+    def test_api_keys_ignored(self):
+        canon = {"auxiliary": {"vision": {"api_key": "sk-old"}}}
+        remote = {"auxiliary": {"vision": {"api_key": "sk-new"}}}
+        drifts = diff_configs(canon, remote)
+        assert len(drifts) == 0
+
+    def test_custom_ignored_keys(self):
+        canon = {"a": 1, "b": 2}
+        remote = {"a": 99, "b": 99}
+        drifts = diff_configs(canon, remote, ignored_keys=["a"])
+        assert len(drifts) == 1
+        assert drifts[0]["key"] == "b"
+
+    def test_multiple_drifts(self):
+        canon = {"model": {"default": "hermes", "provider": "nous"}, "agent": {"max_turns": 30}}
+        remote = {"model": {"default": "gpt-4", "provider": "openai"}, "agent": {"max_turns": 30}}
+        drifts = diff_configs(canon, remote)
+        assert len(drifts) == 2
+        keys = {d["key"] for d in drifts}
+        assert "model.default" in keys
+        assert "model.provider" in keys
+
+    def test_list_values_compared_by_content(self):
+        canon = {"toolsets": ["all"]}
+        remote = {"toolsets": ["terminal", "file"]}
+        drifts = diff_configs(canon, remote)
+        assert len(drifts) == 1
+        assert drifts[0]["drift_type"] == "changed"
+
+
+# ── Sync Patch ───────────────────────────────────────────────────────────────
+
+class TestGenerateSyncPatch:
+    def test_empty_when_identical(self):
+        cfg = {"model": {"default": "hermes"}}
+        assert generate_sync_patch(cfg, cfg) == {}
+
+    def test_patches_changed_values(self):
+        canon = {"model": {"default": "hermes"}}
+        remote = {"model": {"default": "gpt-4"}}
+        patch = generate_sync_patch(canon, remote)
+        assert patch["model.default"] == "hermes"
+
+    def test_patches_missing_keys(self):
+        canon = {"model": {"default": "hermes"}, "agent": {"max_turns": 30}}
+        remote = {"model": {"default": "hermes"}}
+        patch = generate_sync_patch(canon, remote)
+        assert patch["agent.max_turns"] == 30
+
+    def test_does_not_delete_extra_keys(self):
+        canon = {"model": {"default": "hermes"}}
+        remote = {"model": {"default": "hermes"}, "extra": 1}
+        patch = generate_sync_patch(canon, remote)
+        assert "extra" not in patch
+
+
+# ── Formatting ───────────────────────────────────────────────────────────────
+
+class TestFormatting:
+    def test_drift_markdown_no_drift(self):
+        text = format_drift_markdown([])
+        assert "no drift" in text.lower()
+
+    def test_drift_markdown_with_drifts(self):
+        drifts = [
+            {"key": "model.default", "canonical_value": "hermes", "remote_value": "gpt-4", "drift_type": "changed"},
+        ]
+        text = format_drift_markdown(drifts)
+        assert "model.default" in text
+        assert "hermes" in text
+        assert "gpt-4" in text
+        assert "changed" in text
+
+    def test_drift_markdown_caps_at_30(self):
+        drifts = [
+            {"key": f"key.{i}", "canonical_value": "a", "remote_value": "b", "drift_type": "changed"}
+            for i in range(50)
+        ]
+        text = format_drift_markdown(drifts)
+        assert "and 20 more" in text
+
+    def test_report_format_has_sections(self):
+        report = {
+            "timestamp": "2026-04-15T12:00:00+00:00",
+            "canonical_config": "config.yaml",
+            "total_nodes": 4,
+            "reachable": 3,
+            "unreachable": 1,
+            "drifted_nodes": 1,
+            "clean_nodes": 2,
+            "total_drifts": 3,
+            "nodes": {
+                "allegro": {
+                    "host": "167.99.126.228",
+                    "reachable": True,
+                    "machine_type": "vps",
+                    "config_keys": 25,
+                    "has_drift": True,
+                    "drift_count": 3,
+                    "drifts": [
+                        {"key": "model.default", "canonical_value": "hermes", "remote_value": "gpt-4", "drift_type": "changed"},
+                        {"key": "agent.max_turns", "canonical_value": 30, "remote_value": 50, "drift_type": "changed"},
+                        {"key": "terminal.timeout", "canonical_value": 180, "remote_value": None, "drift_type": "missing_remote"},
+                    ],
+                },
+                "timmy": {
+                    "host": "localhost",
+                    "reachable": True,
+                    "machine_type": "mac",
+                    "config_keys": 30,
+                    "has_drift": False,
+                    "drift_count": 0,
+                    "drifts": [],
+                },
+                "ezra": {
+                    "host": "143.198.27.163",
+                    "reachable": False,
+                    "drift_count": -1,
+                    "error": "Could not fetch config",
+                    "drifts": [],
+                },
+            },
+        }
+        text = format_report(report)
+        assert "CONFIG DRIFT DETECTION" in text
+        assert "allegro" in text.lower()
+        assert "UNREACHABLE" in text
+        assert "model.default" in text
+        assert "no drift" in text.lower()  # timmy