diff --git a/mcp_paths.toml b/mcp_paths.toml
deleted file mode 100644
index b6469eda..00000000
--- a/mcp_paths.toml
+++ /dev/null
@@ -1,4 +0,0 @@
-[allowed_paths]
-extra_dirs = [
-    "C:/projects/gencpp",
-]
diff --git a/opencode.json b/opencode.json
deleted file mode 100644
index 62aa4d66..00000000
--- a/opencode.json
+++ /dev/null
@@ -1,86 +0,0 @@
-{
-  "$schema": "https://opencode.ai/config.json",
-  "model": "zai/glm-5",
-  "small_model": "zai/glm-4-flash",
-  "provider": {
-    "zai": {
-      "options": {
-        "timeout": 300000
-      }
-    }
-  },
-  "instructions": [
-    "CLAUDE.md",
-    "conductor/product.md",
-    "conductor/product-guidelines.md",
-    "conductor/workflow.md",
-    "conductor/tech-stack.md"
-  ],
-  "default_agent": "tier2-tech-lead",
-  "mcp": {
-    "manual-slop": {
-      "type": "local",
-      "command": [
-        "C:\\Users\\Ed\\scoop\\apps\\uv\\current\\uv.exe",
-        "run",
-        "python",
-        "C:\\projects\\manual_slop\\scripts\\mcp_server.py"
-      ],
-      "enabled": true,
-      "timeout": 30000,
-      "environment": {
-        "PYTHONPATH": "C:\\projects\\manual_slop\\src",
-        "GIT_TERMINAL_PROMPT": "0",
-        "GCM_INTERACTIVE": "never",
-        "GIT_ASKPASS": "echo",
-        "HOME": "C:\\Users\\Ed"
-      }
-    }
-  },
-  "agent": {
-    "build": {
-      "model": "zai/glm-5",
-      "permission": {
-        "edit": "ask",
-        "bash": "ask"
-      }
-    },
-    "plan": {
-      "model": "zai/glm-5",
-      "permission": {
-        "edit": "deny",
-        "bash": {
-          "*": "ask",
-          "git status*": "allow",
-          "git diff*": "allow",
-          "git log*": "allow"
-        }
-      }
-    }
-  },
-  "permission": {
-    "edit": "ask",
-    "bash": "ask"
-  },
-  "share": "manual",
-  "autoupdate": true,
-  "compaction": {
-    "auto": false,
-    "prune": false,
-    "reserved": 10000
-  },
-  "watcher": {
-    "ignore": [
-      "node_modules/**",
-      ".venv/**",
-      "__pycache__/**",
-      "*.pyc",
-      ".git/**",
-      "logs/**",
-      "*.log"
-    ]
-  },
-  "plugin": [
-    "superpowers@git+https://github.com/obra/superpowers.git"
-  ]
-}
diff --git a/scripts/tier2/artifacts/code_path_audit_phase_2_20260624/test_mcp_schemas.py b/scripts/tier2/artifacts/code_path_audit_phase_2_20260624/test_mcp_schemas.py
new file mode 100644
index 00000000..d1353063
--- /dev/null
+++ b/scripts/tier2/artifacts/code_path_audit_phase_2_20260624/test_mcp_schemas.py
@@ -0,0 +1,4 @@
+from src.mcp_client import get_tool_schemas
+schemas = get_tool_schemas()
+print(f"get_tool_schemas returned {len(schemas)} entries")
+print(f"First: {schemas[0]['name']}")
diff --git a/scripts/tier2/artifacts/code_path_audit_phase_2_20260624/test_provider_history.py b/scripts/tier2/artifacts/code_path_audit_phase_2_20260624/test_provider_history.py
new file mode 100644
index 00000000..335037b9
--- /dev/null
+++ b/scripts/tier2/artifacts/code_path_audit_phase_2_20260624/test_provider_history.py
@@ -0,0 +1,11 @@
+from src.provider_state import get_history
+h = get_history("anthropic")
+h.append({"role": "user", "content": "hi"})
+h.append({"role": "assistant", "content": "hello"})
+print(f"len: {len(h)}")
+print(f"bool: {bool(h)}")
+roles = [m["role"] for m in h]
+print(f"iter: {roles}")
+print(f"getitem: {h[0]}")
+h.clear()
+print(f"after clear len: {len(h)}")
diff --git a/scripts/tier2/artifacts/metadata_nil_sentinel_20260624/find_metadata_nil_funcs.py b/scripts/tier2/artifacts/metadata_nil_sentinel_20260624/find_metadata_nil_funcs.py
new file mode 100644
index 00000000..3ad447c6
--- /dev/null
+++ b/scripts/tier2/artifacts/metadata_nil_sentinel_20260624/find_metadata_nil_funcs.py
@@ -0,0 +1,28 @@
+import sys
+sys.path.insert(0, ".")
+import ast
+from pathlib import Path
+
+# Strict: find functions where a parameter is DIRECTLY typed as Metadata (not nested)
+for fpath in Path("src").glob("*.py"):
+    src = fpath.read_text(encoding="utf-8")
+    tree = ast.parse(src)
+    for node in ast.walk(tree):
+        if not isinstance(node, (ast.FunctionDef, ast.AsyncFunctionDef)):
+            continue
+        for arg in node.args.args + node.args.kwonlyargs:
+            if arg.annotation is None:
+                continue
+            ann_str = ast.unparse(arg.annotation)
+            is_metadata_direct = ann_str in ("Metadata", "dict[str, Any]", "Optional[Metadata]", "Optional[dict[str, Any]]")
+            if not is_metadata_direct:
+                continue
+            # Check if there's a nil-check on this parameter
+            for sub in ast.walk(node):
+                if isinstance(sub, ast.Compare):
+                    left = sub.left
+                    if isinstance(left, ast.Name) and left.id == arg.arg:
+                        for c in sub.comparators:
+                            if isinstance(c, ast.Constant) and c.value is None:
+                                print(f"  {fpath.name}:{node.lineno} {node.name} - param={arg.arg} ann={ann_str} nil@{sub.lineno}")
+                                break
diff --git a/scripts/tier2/artifacts/metadata_nil_sentinel_20260624/find_nil_funcs.py b/scripts/tier2/artifacts/metadata_nil_sentinel_20260624/find_nil_funcs.py
new file mode 100644
index 00000000..bdf2b290
--- /dev/null
+++ b/scripts/tier2/artifacts/metadata_nil_sentinel_20260624/find_nil_funcs.py
@@ -0,0 +1,13 @@
+import sys
+sys.path.insert(0, ".")
+from src.code_path_audit_ssdl import detect_nil_check_pattern
+from src.code_path_audit import build_pcg
+
+r = build_pcg("src")
+pcg = r.data
+
+metadata_consumers = pcg.consumers.get("Metadata", [])
+nil_funcs = [f for f in metadata_consumers if detect_nil_check_pattern(f, "src")]
+print(f"Total Metadata consumers with nil-checks: {len(nil_funcs)}")
+for f in nil_funcs:
+    print(f"  - {f.fqname} @ {f.file}:{f.line}")
diff --git a/scripts/tier2/artifacts/metadata_nil_sentinel_20260624/find_nil_in_files.py b/scripts/tier2/artifacts/metadata_nil_sentinel_20260624/find_nil_in_files.py
new file mode 100644
index 00000000..8b6f1c93
--- /dev/null
+++ b/scripts/tier2/artifacts/metadata_nil_sentinel_20260624/find_nil_in_files.py
@@ -0,0 +1,30 @@
+import sys
+sys.path.insert(0, ".")
+import ast
+from pathlib import Path
+
+for fpath in ("src/aggregate.py", "src/ai_client.py"):
+    p = Path(fpath)
+    src = p.read_text(encoding="utf-8")
+    tree = ast.parse(src)
+    print(f"=== {fpath} ===")
+    for node in ast.walk(tree):
+        if isinstance(node, (ast.FunctionDef, ast.AsyncFunctionDef)):
+            has_nil = False
+            nil_vars = []
+            for sub in ast.walk(node):
+                if isinstance(sub, ast.Compare):
+                    for ci, c in enumerate(sub.comparators):
+                        if isinstance(c, ast.Constant) and c.value is None:
+                            has_nil = True
+                            left = sub.left
+                            if isinstance(left, ast.Name):
+                                nil_vars.append((left.id, sub.lineno))
+                            else:
+                                nil_vars.append(("?", sub.lineno))
+            if has_nil:
+                # Check parameters
+                params = []
+                for arg in node.args.args + node.args.kwonlyargs:
+                    params.append(arg.arg)
+                print(f"  line {node.lineno}: {node.name} - nil_vars: {nil_vars[:5]}, params: {params[:8]}")
diff --git a/scripts/tier2/artifacts/metadata_nil_sentinel_20260624/vc2_check.py b/scripts/tier2/artifacts/metadata_nil_sentinel_20260624/vc2_check.py
new file mode 100644
index 00000000..f07ed0fb
--- /dev/null
+++ b/scripts/tier2/artifacts/metadata_nil_sentinel_20260624/vc2_check.py
@@ -0,0 +1,14 @@
+import sys
+sys.path.insert(0, ".")
+from src.code_path_audit_ssdl import detect_nil_check_pattern
+from src.code_path_audit import FunctionRef
+
+fref = FunctionRef(
+    fqname="src.aggregate._build_files_section_from_items",
+    file="aggregate.py",
+    line=300,
+    role="consumer",
+)
+result = detect_nil_check_pattern(fref, "src")
+print(f"detect_nil_check_pattern(_build_files_section_from_items) = {result}")
+print("PASS" if not result else "FAIL")
diff --git a/scripts/tier2/artifacts/metadata_nil_sentinel_20260624/vc4_budget_gate.py b/scripts/tier2/artifacts/metadata_nil_sentinel_20260624/vc4_budget_gate.py
new file mode 100644
index 00000000..d00e3935
--- /dev/null
+++ b/scripts/tier2/artifacts/metadata_nil_sentinel_20260624/vc4_budget_gate.py
@@ -0,0 +1,49 @@
+import sys
+sys.path.insert(0, ".")
+from src.code_path_audit_ssdl import compute_effective_codepaths
+from src.code_path_audit import build_pcg, FunctionRef
+from src.code_path_audit_analysis import aggregate_pattern_from_consumers
+from src.code_path_audit_cross_audit import (
+    aggregate_findings,
+    build_cross_audit_findings_for_aggregate,
+)
+from src.code_path_audit_analysis import (
+    compute_real_type_alias_coverage,
+    compute_real_decomposition_cost,
+    extract_real_optimization_candidates,
+)
+from src.code_path_audit import AggregateProfile, ResultCoverage, TypeAliasCoverage, CrossAuditFindings, DecompositionCost, FrequencyEvidence
+from src.code_path_audit import classify_memory_dim
+
+pcg_result = build_pcg("src")
+pcg = pcg_result.data
+
+producers = tuple(pcg.producers.get("Metadata", []))
+consumers = tuple(pcg.consumers.get("Metadata", []))
+print(f"Producers: {len(producers)}")
+print(f"Consumers: {len(consumers)}")
+
+profile = AggregateProfile(
+    name="Metadata",
+    aggregate_kind="typealias",
+    memory_dim=classify_memory_dim("Metadata", producers[0].file if producers else "", {}),
+    producers=producers,
+    consumers=consumers,
+    access_pattern="mixed",
+    access_pattern_evidence=(),
+    frequency="per_turn",
+    frequency_evidence=(),
+    result_coverage=ResultCoverage(0, 0, 0, 0, ""),
+    type_alias_coverage=TypeAliasCoverage(0, 0, 0, ""),
+    cross_audit_findings=CrossAuditFindings((), (), (), (), ()),
+    decomposition_cost=DecompositionCost(0, 0, 0, "insufficient_data", "", None, 0, False),
+    optimization_candidates=(),
+    is_candidate=False,
+)
+
+ec = compute_effective_codepaths(profile, "src")
+print(f"Effective codepaths: {ec}")
+print(f"Baseline: 4.01e22")
+print(f"Drop: {4.01e22 - ec}")
+print(f"Drop %: {(4.01e22 - ec) / 4.01e22 * 100:.6f}%")
+print(f"VC4: {'PASS' if ec <= 4.01e22 * 0.9 else 'FAIL'} (need 10% drop)")