diff --git a/lang/src/mir/min_emitter.hako b/lang/src/mir/min_emitter.hako
index 8b0653c5..2ef52e22 100644
--- a/lang/src/mir/min_emitter.hako
+++ b/lang/src/mir/min_emitter.hako
@@ -111,4 +111,8 @@ static box MinMirEmitter {
   }
 }
 
-static box MinMirEmitterMain { main(args){ return 0 } }
+using "lang/src/shared/common/entry_point_base.hako" as EntryPointBaseBox
+
+static box MinMirEmitterMain {
+  main(args) { return EntryPointBaseBox.main(args) }
+}
diff --git a/lang/src/shared/common/common_imports.hako b/lang/src/shared/common/common_imports.hako
new file mode 100644
index 00000000..b9396ff3
--- /dev/null
+++ b/lang/src/shared/common/common_imports.hako
@@ -0,0 +1,18 @@
+// CommonImportsBox - Unified import utilities for string operations
+// Consolidates frequently used StringHelpers and StringOps imports
+
+using "lang/src/shared/common/string_helpers.hako" as StringHelpers
+using selfhost.shared.common.string_ops as StringOps
+
+static box CommonImportsBox {
+  // Provides access to common string utilities
+  // Boxes can import this instead of individual modules
+  static helpers() { return StringHelpers }
+  static ops() { return StringOps }
+  
+  // Commonly used string operations
+  static read_digits(text, pos) { return StringHelpers.read_digits(text, pos) }
+  static to_i64(digits) { return StringHelpers.to_i64(digits) }
+  static index_of_from(text, pattern, start) { return StringOps.index_of_from(text, pattern, start) }
+  static substring(text, start, end) { return StringOps.substring(text, start, end) }
+}
diff --git a/lang/src/shared/common/entry_point_base.hako b/lang/src/shared/common/entry_point_base.hako
new file mode 100644
index 00000000..9715a7d8
--- /dev/null
+++ b/lang/src/shared/common/entry_point_base.hako
@@ -0,0 +1,18 @@
+// EntryPointBaseBox - Common entry point for standalone boxes
+// Eliminates repetitive main(args){ return 0 } boilerplate
+
+static box EntryPointBaseBox {
+  // Standard entry point implementation
+  // Can be overridden by specific boxes if needed
+  static main(args) {
+    return 0
+  }
+  
+  // Entry point with validation
+  static safe_main(args) {
+    if args == null {
+      return 1
+    }
+    return EntryPointBaseBox.main(args)
+  }
+}
diff --git a/lang/src/shared/mir/mir_io_box.hako b/lang/src/shared/mir/mir_io_box.hako
index 736cca10..dfdd9c4e 100644
--- a/lang/src/shared/mir/mir_io_box.hako
+++ b/lang/src/shared/mir/mir_io_box.hako
@@ -16,7 +16,7 @@ using "lang/src/vm/hakorune-vm/blocks_locator.hako" as BlocksLocatorBox
 using "lang/src/vm/hakorune-vm/instrs_locator.hako" as InstrsLocatorBox
 using "lang/src/vm/hakorune-vm/backward_object_scanner.hako" as BackwardObjectScannerBox
 using "lang/src/vm/hakorune-vm/block_iterator.hako" as BlockIteratorBox
-using selfhost.shared.common.string_helpers as StringHelpers
+using "lang/src/shared/common/common_imports.hako" as CommonImports
 using selfhost.shared.common.box_helpers as BoxHelpers
 
 static box MirIoBox {
@@ -144,7 +144,7 @@ static box MirIoBox {
       p = p + key_id.length()
       // skip ws
       loop(p < obj.length()) { local ch = obj.substring(p,p+1) if ch == " " || ch == "\n" || ch == "\r" || ch == "\t" { p = p + 1 continue } break }
-      local digs = StringHelpers.read_digits(obj, p)
+      local digs = CommonImports.read_digits(obj, p)
       if digs == "" { return Result.Err("invalid block id") }
       ids.set(StringHelpers.int_to_str(StringHelpers.to_i64(digs)), 1)
       // require terminator
diff --git a/lang/src/vm/hakorune-vm/core_bridge_ops.hako b/lang/src/vm/hakorune-vm/core_bridge_ops.hako
index c0d481e7..d2be0188 100644
--- a/lang/src/vm/hakorune-vm/core_bridge_ops.hako
+++ b/lang/src/vm/hakorune-vm/core_bridge_ops.hako
@@ -4,6 +4,7 @@
 
 using "lang/src/vm/boxes/result_box.hako" as Result
 using "lang/src/vm/hakorune-vm/json_field_extractor.hako" as JsonFieldExtractor
+using "lang/src/vm/hakorune-vm/inst_field_extractor.hako" as InstFieldExtractor
 using "lang/src/vm/hakorune-vm/value_manager.hako" as ValueManagerBox
 using "lang/src/vm/hakorune-vm/args_extractor.hako" as ArgsExtractorBox
 using "lang/src/shared/common/string_helpers.hako" as StringHelpers
@@ -36,8 +37,8 @@ static box CoreBridgeOps {
     local st = NyVmState.birth()
     local rc = NyVmOpConst.handle(inst_json, st)
     if rc < 0 { return Result.Err("const: core failure") }
-    // Reflect dst into hakorune-vm regs
-    local dst = JsonFieldExtractor.extract_int(inst_json, "dst")
+    // Reflect dst into hakorune-vm regs using unified extractor
+    local dst = InstFieldExtractor.extract_dst(inst_json)
     if dst == null { return Result.Err("const: dst not found") }
     local v = NyVmState.get_reg(st, dst)
     ValueManagerBox.set(regs, dst, v)
@@ -46,40 +47,30 @@ static box CoreBridgeOps {
 
   // Apply binop via Core
   apply_binop(inst_json, regs) {
-    // Extract required fields
-    local dst = JsonFieldExtractor.extract_int(inst_json, "dst")
+    // Extract required fields using unified extractor
+    local dst = InstFieldExtractor.extract_dst(inst_json)
     if dst == null { return Result.Err("binop: dst field not found") }
-    local lhs = JsonFieldExtractor.extract_int(inst_json, "lhs")
-    if lhs == null { return Result.Err("binop: lhs field not found") }
-    local rhs = JsonFieldExtractor.extract_int(inst_json, "rhs")
-    if rhs == null { return Result.Err("binop: rhs field not found") }
+    local binary_ops = InstFieldExtractor.extract_binary_ops(inst_json)
+    if binary_ops.lhs == null { return Result.Err("binop: lhs field not found") }
+    if binary_ops.rhs == null { return Result.Err("binop: rhs field not found") }
 
-    // Normalize operation: prefer symbolic 'operation', else map from 'op_kind'
-    local op = JsonFieldExtractor.extract_string(inst_json, "operation")
-    if op == null {
-      local kind = JsonFieldExtractor.extract_string(inst_json, "op_kind")
-      if kind == null { return Result.Err("binop: operation/op_kind not found") }
-      if kind == "Add" { op = "+" }
-      else if kind == "Sub" { op = "-" }
-      else if kind == "Mul" { op = "*" }
-      else if kind == "Div" { op = "/" }
-      else if kind == "Mod" { op = "%" }
-      else { return Result.Err("binop: unsupported op_kind: " + kind) }
-    }
+    // Use unified binary ops extractor (includes operation normalization)
+    local op = binary_ops.operation
+    if op == null { return Result.Err("binop: operation/op_kind not found") }
 
     // Guard: required src regs must be set
-    local lhs_val = ValueManagerBox.get(regs, lhs)
-    if lhs_val == null { return Result.Err("binop: lhs v%" + lhs + " is unset") }
-    local rhs_val = ValueManagerBox.get(regs, rhs)
-    if rhs_val == null { return Result.Err("binop: rhs v%" + rhs + " is unset") }
+    local lhs_val = ValueManagerBox.get(regs, binary_ops.lhs)
+    if lhs_val == null { return Result.Err("binop: lhs v%" + binary_ops.lhs + " is unset") }
+    local rhs_val = ValueManagerBox.get(regs, binary_ops.rhs)
+    if rhs_val == null { return Result.Err("binop: rhs v%" + binary_ops.rhs + " is unset") }
 
     // Rebuild minimal JSON acceptable to Core
-    local j = "{\"op\":\"binop\",\"dst\":" + dst + ",\"operation\":\"" + op + "\",\"lhs\":" + lhs + ",\"rhs\":" + rhs + "}"
+    local j = "{\"op\":\"binop\",\"dst\":" + dst + ",\"operation\":\"" + op + "\",\"lhs\":" + binary_ops.lhs + ",\"rhs\":" + binary_ops.rhs + "}"
 
     // Execute via Core with a temporary state containing sources
     local st = NyVmState.birth()
-    NyVmState.set_reg(st, lhs, lhs_val)
-    NyVmState.set_reg(st, rhs, rhs_val)
+    NyVmState.set_reg(st, binary_ops.lhs, lhs_val)
+    NyVmState.set_reg(st, binary_ops.rhs, rhs_val)
     local rc = NyVmOpBinOp.handle(j, st)
     if rc < 0 { return Result.Err("binop: core failure") }
     local out = NyVmState.get_reg(st, dst)
@@ -101,35 +92,24 @@ static box CoreBridgeOps {
 
   // Apply compare via Core
   apply_compare(inst_json, regs) {
-    local dst = JsonFieldExtractor.extract_int(inst_json, "dst")
+    local dst = InstFieldExtractor.extract_dst(inst_json)
     if dst == null { return Result.Err("compare: dst field not found") }
-    local lhs = JsonFieldExtractor.extract_int(inst_json, "lhs")
-    if lhs == null { return Result.Err("compare: lhs field not found") }
-    local rhs = JsonFieldExtractor.extract_int(inst_json, "rhs")
-    if rhs == null { return Result.Err("compare: rhs field not found") }
-    // Normalize kind -> operation
-    local op = JsonFieldExtractor.extract_string(inst_json, "operation")
-    if op == null {
-      local kind = JsonFieldExtractor.extract_string(inst_json, "kind")
-      if kind == null { return Result.Err("compare: kind/operation not found") }
-      if kind == "Eq" { op = "==" }
-      else if kind == "Ne" { op = "!=" }
-      else if kind == "Lt" { op = "<" }
-      else if kind == "Le" { op = "<=" }
-      else if kind == "Gt" { op = ">" }
-      else if kind == "Ge" { op = ">=" }
-      else { return Result.Err("compare: unsupported kind: " + kind) }
-    }
+    local compare_ops = InstFieldExtractor.extract_compare_ops(inst_json)
+    if compare_ops.lhs == null { return Result.Err("compare: lhs field not found") }
+    if compare_ops.rhs == null { return Result.Err("compare: rhs field not found") }
+    // Use unified compare ops extractor (includes operation normalization)
+    local op = compare_ops.operation
+    if op == null { return Result.Err("compare: kind/operation not found") }
     // Guards
-    local lv = ValueManagerBox.get(regs, lhs)
-    if lv == null { return Result.Err("compare: lhs v%" + lhs + " is unset") }
-    local rv = ValueManagerBox.get(regs, rhs)
-    if rv == null { return Result.Err("compare: rhs v%" + rhs + " is unset") }
+    local lv = ValueManagerBox.get(regs, compare_ops.lhs)
+    if lv == null { return Result.Err("compare: lhs v%" + compare_ops.lhs + " is unset") }
+    local rv = ValueManagerBox.get(regs, compare_ops.rhs)
+    if rv == null { return Result.Err("compare: rhs v%" + compare_ops.rhs + " is unset") }
     // Build minimal JSON
-    local j = "{\"op\":\"compare\",\"dst\":" + dst + ",\"operation\":\"" + op + "\",\"lhs\":" + lhs + ",\"rhs\":" + rhs + "}"
+    local j = "{\"op\":\"compare\",\"dst\":" + dst + ",\"operation\":\"" + op + "\",\"lhs\":" + compare_ops.lhs + ",\"rhs\":" + compare_ops.rhs + "}"
     local st = NyVmState.birth()
-    NyVmState.set_reg(st, lhs, lv)
-    NyVmState.set_reg(st, rhs, rv)
+    NyVmState.set_reg(st, compare_ops.lhs, lv)
+    NyVmState.set_reg(st, compare_ops.rhs, rv)
     local rc = NyVmOpCompare.handle(j, st)
     if rc < 0 { return Result.Err("compare: core failure") }
     ValueManagerBox.set(regs, dst, NyVmState.get_reg(st, dst))
diff --git a/lang/src/vm/hakorune-vm/inst_field_extractor.hako b/lang/src/vm/hakorune-vm/inst_field_extractor.hako
index 8d5444f5..c7f85d92 100644
--- a/lang/src/vm/hakorune-vm/inst_field_extractor.hako
+++ b/lang/src/vm/hakorune-vm/inst_field_extractor.hako
@@ -23,12 +23,24 @@ static box InstFieldExtractorBox {
     return result
   }
   
-  // Extract comparison fields (lhs, rhs, kind)
+  // Extract comparison fields (lhs, rhs, kind) and normalize to operation
   static extract_compare_ops(inst_json) {
     local result = {}
     result.lhs = JsonFieldExtractor.extract_int(inst_json, "lhs")
     result.rhs = JsonFieldExtractor.extract_int(inst_json, "rhs")
     result.kind = JsonFieldExtractor.extract_string(inst_json, "kind")
+    
+    // Normalize kind -> operation
+    local op = JsonFieldExtractor.extract_string(inst_json, "operation")
+    if op == null && result.kind != null {
+      if result.kind == "Eq" { op = "==" }
+      else if result.kind == "Ne" { op = "!=" }
+      else if result.kind == "Lt" { op = "<" }
+      else if result.kind == "Le" { op = "<=" }
+      else if result.kind == "Gt" { op = ">" }
+      else if result.kind == "Ge" { op = ">=" }
+    }
+    result.operation = op
     return result
   }
   
diff --git a/src/backend/mir_interpreter/handlers/boxes_map.rs b/src/backend/mir_interpreter/handlers/boxes_map.rs
index 2557a0fb..9f696429 100644
--- a/src/backend/mir_interpreter/handlers/boxes_map.rs
+++ b/src/backend/mir_interpreter/handlers/boxes_map.rs
@@ -64,7 +64,12 @@ pub(super) fn try_handle_map_box(
                 }
                 "set" => {
                     if args.len() != 2 { return Err(VMError::InvalidInstruction("MapBox.set expects 2 args".into())); }
-                    let k = this.reg_load(args[0])?.to_nyash_box();
+                    let k_vm = this.reg_load(args[0])?;
+                    if !matches!(k_vm, VMValue::String(_)) {
+                        if let Some(d) = dst { this.regs.insert(d, VMValue::String("[map/bad-key] key must be string".to_string())); }
+                        return Ok(true);
+                    }
+                    let k = k_vm.to_nyash_box();
                     let v = this.reg_load(args[1])?.to_nyash_box();
                     let ret = mb.set(k, v);
                     if let Some(d) = dst { this.regs.insert(d, VMValue::from_nyash_box(ret)); }
@@ -72,7 +77,12 @@ pub(super) fn try_handle_map_box(
                 }
                 "get" => {
                     if args.len() != 1 { return Err(VMError::InvalidInstruction("MapBox.get expects 1 arg".into())); }
-                    let k = this.reg_load(args[0])?.to_nyash_box();
+                    let k_vm = this.reg_load(args[0])?;
+                    if !matches!(k_vm, VMValue::String(_)) {
+                        if let Some(d) = dst { this.regs.insert(d, VMValue::String("[map/bad-key] key must be string".to_string())); }
+                        return Ok(true);
+                    }
+                    let k = k_vm.to_nyash_box();
                     let ret = mb.get(k);
                     if let Some(d) = dst { this.regs.insert(d, VMValue::from_nyash_box(ret)); }
                     return Ok(true);
@@ -86,7 +96,12 @@ pub(super) fn try_handle_map_box(
                 }
                 "delete" => {
                     if args.len() != 1 { return Err(VMError::InvalidInstruction("MapBox.delete expects 1 arg".into())); }
-                    let k = this.reg_load(args[0])?.to_nyash_box();
+                    let k_vm = this.reg_load(args[0])?;
+                    if !matches!(k_vm, VMValue::String(_)) {
+                        if let Some(d) = dst { this.regs.insert(d, VMValue::String("[map/bad-key] key must be string".to_string())); }
+                        return Ok(true);
+                    }
+                    let k = k_vm.to_nyash_box();
                     let ret = mb.delete(k);
                     if let Some(d) = dst { this.regs.insert(d, VMValue::from_nyash_box(ret)); }
                     return Ok(true);
diff --git a/src/runner/json_v1_bridge.rs b/src/runner/json_v1_bridge.rs
index 990796b8..9101a6f7 100644
--- a/src/runner/json_v1_bridge.rs
+++ b/src/runner/json_v1_bridge.rs
@@ -467,6 +467,16 @@ pub fn try_parse_v1_to_module(json: &str) -> Result<Option<MirModule>, String> {
                                         "mir_call callee Closure missing func in function '{}'",
                                         func_name
                                     ))? as u32;
+                                // If captures exist, append them to argv (best-effort minimal semantics)
+                                if let Some(caps) = callee_obj.get("captures").and_then(Value::as_array) {
+                                    for c in caps {
+                                        let id = c.as_u64().ok_or_else(|| format!(
+                                            "mir_call Closure capture must be integer in function '{}'",
+                                            func_name
+                                        ))? as u32;
+                                        argv.push(ValueId::new(id));
+                                    }
+                                }
                                 // Captures (if any) are currently ignored at this stage; captured values are
                                 // expected to be materialized as arguments or handled by earlier lowering.
                                 block_ref.add_instruction(MirInstruction::Call {
diff --git a/tools/smokes/v2/profiles/quick/core/bridge/canonicalize_noop_method_on_vm.sh b/tools/smokes/v2/profiles/quick/core/bridge/canonicalize_noop_method_on_vm.sh
new file mode 100644
index 00000000..3ef680f5
--- /dev/null
+++ b/tools/smokes/v2/profiles/quick/core/bridge/canonicalize_noop_method_on_vm.sh
@@ -0,0 +1,35 @@
+#!/bin/bash
+# canonicalize_noop_method_on_vm.sh — ONでもMethodは変異しない（dump-mut未生成）
+
+set -euo pipefail
+
+SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
+if ROOT_GIT=$(git -C "$SCRIPT_DIR" rev-parse --show-toplevel 2>/dev/null); then
+  ROOT="$ROOT_GIT"
+else
+  ROOT="$(cd "$SCRIPT_DIR/../../../../../../../../.." && pwd)"
+fi
+source "$ROOT/tools/smokes/v2/lib/test_runner.sh"
+require_env || exit 2
+
+json_path="/tmp/ny_v1_noop_method_$$.json"
+mut_on="/tmp/ny_v1_noop_method_on_$$.json"
+
+cat >"$json_path" <<'JSON'
+{"schema_version":"1.0","functions":[{"name":"main","blocks":[{"id":0,"instructions":[{"op":"mir_call","mir_call":{"callee":{"type":"Method","box_name":"ArrayBox","method":"size","receiver":1},"args":[] }},{"op":"ret"}]}]}]}
+JSON
+
+set +e
+HAKO_NYVM_V1_DOWNCONVERT=1 HAKO_BRIDGE_INJECT_SINGLETON=1 HAKO_DEBUG_NYVM_BRIDGE_DUMP_MUT="$mut_on" \
+  "$ROOT/target/release/nyash" --json-file "$json_path" >/dev/null 2>&1
+set -e || true
+
+if [ -f "$mut_on" ]; then
+  echo "[FAIL] canonicalize_noop_method_on_vm: mutated dump should not be created for Method" >&2
+  exit 1
+fi
+
+echo "[PASS] canonicalize_noop_method_on_vm"
+rm -f "$json_path" "$mut_on"
+exit 0
+
diff --git a/tools/smokes/v2/profiles/quick/core/gate_c_invalid_header_vm.sh b/tools/smokes/v2/profiles/quick/core/gate_c_invalid_header_vm.sh
new file mode 100644
index 00000000..f312ef2a
--- /dev/null
+++ b/tools/smokes/v2/profiles/quick/core/gate_c_invalid_header_vm.sh
@@ -0,0 +1,27 @@
+#!/bin/bash
+# gate_c_invalid_header_vm.sh — Gate‑C(Core) invalid JSON header → 非0終了
+
+set -euo pipefail
+SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
+if ROOT_GIT=$(git -C "$SCRIPT_DIR" rev-parse --show-toplevel 2>/dev/null); then
+  ROOT="$ROOT_GIT"
+else
+  ROOT="$(cd "$SCRIPT_DIR/../../../../../../.." && pwd)"
+fi
+source "$ROOT/tools/smokes/v2/lib/test_runner.sh"
+require_env || exit 2
+
+bad="/tmp/gatec_bad_$$.json"
+echo '{"bad":1}' > "$bad"
+set +e
+NYASH_GATE_C_CORE=1 "$NYASH_BIN" --nyvm-json-file "$bad" >/dev/null 2>&1
+rc=$?
+set -e
+rm -f "$bad"
+if [ $rc -ne 0 ]; then
+  echo "[PASS] gate_c_invalid_header_vm"
+else
+  echo "[FAIL] gate_c_invalid_header_vm (rc=$rc)" >&2
+  exit 1
+fi
+
diff --git a/tools/smokes/v2/profiles/quick/core/map/map_bad_key_delete_vm.sh b/tools/smokes/v2/profiles/quick/core/map/map_bad_key_delete_vm.sh
new file mode 100644
index 00000000..284c2ae6
--- /dev/null
+++ b/tools/smokes/v2/profiles/quick/core/map/map_bad_key_delete_vm.sh
@@ -0,0 +1,21 @@
+#!/bin/bash
+# map_bad_key_delete_vm.sh — Map.delete with non-string key returns [map/bad-key]
+
+set -euo pipefail
+SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
+if ROOT_GIT=$(git -C "$SCRIPT_DIR" rev-parse --show-toplevel 2>/dev/null); then
+  ROOT="$ROOT_GIT"
+else
+  ROOT="$(cd "$SCRIPT_DIR/../../../../../../../../.." && pwd)"
+fi
+source "$ROOT/tools/smokes/v2/lib/test_runner.sh"
+require_env || exit 2
+
+code='static box Main { main() { local m=new MapBox(); print(m.delete(123)); return 0 } }'
+out=$(run_nyash_vm -c "$code")
+if echo "$out" | grep -q "\[map/bad-key\]"; then
+  echo "[PASS] map_bad_key_delete_vm"
+else
+  echo "[FAIL] map_bad_key_delete_vm" >&2; echo "$out" >&2; exit 1
+fi
+
diff --git a/tools/smokes/v2/profiles/quick/core/map/map_bad_key_get_vm.sh b/tools/smokes/v2/profiles/quick/core/map/map_bad_key_get_vm.sh
new file mode 100644
index 00000000..c24e8c39
--- /dev/null
+++ b/tools/smokes/v2/profiles/quick/core/map/map_bad_key_get_vm.sh
@@ -0,0 +1,21 @@
+#!/bin/bash
+# map_bad_key_get_vm.sh — Map.get with non-string key returns [map/bad-key]
+
+set -euo pipefail
+SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
+if ROOT_GIT=$(git -C "$SCRIPT_DIR" rev-parse --show-toplevel 2>/dev/null); then
+  ROOT="$ROOT_GIT"
+else
+  ROOT="$(cd "$SCRIPT_DIR/../../../../../../../../.." && pwd)"
+fi
+source "$ROOT/tools/smokes/v2/lib/test_runner.sh"
+require_env || exit 2
+
+code='static box Main { main() { local m=new MapBox(); print(m.get(123)); return 0 } }'
+out=$(run_nyash_vm -c "$code")
+if echo "$out" | grep -q "\[map/bad-key\]"; then
+  echo "[PASS] map_bad_key_get_vm"
+else
+  echo "[FAIL] map_bad_key_get_vm" >&2; echo "$out" >&2; exit 1
+fi
+
diff --git a/tools/smokes/v2/profiles/quick/core/map/map_bad_key_set_vm.sh b/tools/smokes/v2/profiles/quick/core/map/map_bad_key_set_vm.sh
new file mode 100644
index 00000000..b3e5cee8
--- /dev/null
+++ b/tools/smokes/v2/profiles/quick/core/map/map_bad_key_set_vm.sh
@@ -0,0 +1,21 @@
+#!/bin/bash
+# map_bad_key_set_vm.sh — Map.set with non-string key returns [map/bad-key]
+
+set -euo pipefail
+SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
+if ROOT_GIT=$(git -C "$SCRIPT_DIR" rev-parse --show-toplevel 2>/dev/null); then
+  ROOT="$ROOT_GIT"
+else
+  ROOT="$(cd "$SCRIPT_DIR/../../../../../../../../.." && pwd)"
+fi
+source "$ROOT/tools/smokes/v2/lib/test_runner.sh"
+require_env || exit 2
+
+code='static box Main { main() { local m=new MapBox(); print(m.set(123, 1)); return 0 } }'
+out=$(run_nyash_vm -c "$code")
+if echo "$out" | grep -q "\[map/bad-key\]"; then
+  echo "[PASS] map_bad_key_set_vm"
+else
+  echo "[FAIL] map_bad_key_set_vm" >&2; echo "$out" >&2; exit 1
+fi
+
diff --git a/tools/smokes/v2/profiles/quick/core/string/substring_clamp_vm.sh b/tools/smokes/v2/profiles/quick/core/string/substring_clamp_vm.sh
new file mode 100644
index 00000000..f309244d
--- /dev/null
+++ b/tools/smokes/v2/profiles/quick/core/string/substring_clamp_vm.sh
@@ -0,0 +1,34 @@
+#!/bin/bash
+# substring_clamp_vm.sh — String.substring clamps to [0,size] and start<=end
+
+set -euo pipefail
+
+SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
+if ROOT_GIT=$(git -C "$SCRIPT_DIR" rev-parse --show-toplevel 2>/dev/null); then
+  ROOT="$ROOT_GIT"
+else
+  ROOT="$(cd "$SCRIPT_DIR/../../../../../../../../.." && pwd)"
+fi
+source "$ROOT/tools/smokes/v2/lib/test_runner.sh"
+require_env || exit 2
+
+code='static box Main { main() {
+  local s="abcd";
+  print(s.substring(-5, 2));
+  print(s.substring(2, 99));
+  print(s.substring(3, 1));
+  return 0
+} }'
+out=$(run_nyash_vm -c "$code")
+expected=$(cat <<EOT
+ab
+cd
+
+EOT
+)
+if [ "$out" = "$expected" ]; then
+  echo "[PASS] substring_clamp_vm"
+else
+  echo "[FAIL] substring_clamp_vm" >&2; printf '--- expected ---\n%s--- got ---\n%s\n' "$expected" "$out" >&2; exit 1
+fi
+