diff --git a/CHANGELOG.md b/CHANGELOG.md
index 6eee57a8..8297563c 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -11,6 +11,7 @@
 - Replace all var declarations with let/const for modern JavaScript standards
 - Ensure parseInt calls use explicit radix parameter for clarity and reliability
 - Fix precision loss in test data generators by using JavaScript safe integer limits
+- Add block scoping to switch statement cases to prevent variable declaration issues
 
 ## v0.10.9
 - Add support for IPv6 urls
diff --git a/bin/generate-defs.js b/bin/generate-defs.js
index eae0c447..a9c528b4 100644
--- a/bin/generate-defs.js
+++ b/bin/generate-defs.js
@@ -495,7 +495,7 @@ function decoderFn(method) {
       case 'timestamp':
         println('val = ints.readUInt64BE(buffer, offset); offset += 8;');
         break;
-      case 'bit':
+      case 'bit': {
         const bit = 1 << bitsInARow;
         println('val = !!(buffer[offset] & %d);', bit);
         if (bitsInARow === 7) {
@@ -503,6 +503,7 @@ function decoderFn(method) {
           bitsInARow = 0;
         } else bitsInARow++;
         break;
+      }
       case 'longstr':
         println('len = buffer.readUInt32BE(offset); offset += 4;');
         println('val = buffer.subarray(offset, offset + len);');
@@ -644,12 +645,13 @@ function encodePropsFn(props) {
           println('ints.writeUInt64BE(buffer, val, offset);');
           println('offset += 8;');
           break;
-        case 'shortstr':
+        case 'shortstr': {
           const v = stringLenVar(p);
           println('buffer[offset] = %s; offset++;', v);
           println("buffer.write(val, offset, 'utf8');");
           println('offset += %s;', v);
           break;
+        }
         case 'longstr':
           println('buffer.writeUInt32BE(val.length, offset);');
           println('offset += 4;');
diff --git a/biome.json b/biome.json
index 826cd997..28fd64f3 100644
--- a/biome.json
+++ b/biome.json
@@ -19,15 +19,6 @@
         "noArguments": "off",
         "useLiteralKeys": "off"
       },
-      "correctness": {
-        "noUnusedFunctionParameters": "error",
-        "noUnusedVariables": "error",
-        "noInnerDeclarations": "error",
-        "useParseIntRadix": "error",
-        "noSwitchDeclarations": "off",
-        "noInvalidUseBeforeDeclaration": "error",
-        "noPrecisionLoss": "error"
-      },
       "style": {
         "useConst": "off",
         "useNodejsImportProtocol": "off",
diff --git a/lib/channel.js b/lib/channel.js
index 7e04f9e1..2727a66d 100644
--- a/lib/channel.js
+++ b/lib/channel.js
@@ -287,7 +287,7 @@ class Channel extends EventEmitter {
         // The broker can send this if e.g., the queue is deleted.
         return this.emit('cancel', f.fields);
 
-      case defs.ChannelClose:
+      case defs.ChannelClose: {
         // Any remote closure is an error to us. Reject the pending reply
         // with the close frame, so it can see whether it was that
         // operation that caused it to close.
@@ -308,12 +308,14 @@ class Channel extends EventEmitter {
         const s = stackCapture(emsg);
         this.toClosed(s);
         return;
+      }
 
       case defs.BasicFlow:
         // RabbitMQ doesn't send this, it just blocks the TCP socket
         return this.closeWithError(f.id, 'Flow not implemented', defs.constants.NOT_IMPLEMENTED, new Error('Flow not implemented'));
 
-      default: // assume all other things are replies
+      default: {
+        // assume all other things are replies
         // Resolving the reply may lead to another RPC; to make sure we
         // don't hold that up, clear this.reply
         const reply = this.reply;
@@ -328,6 +330,7 @@ class Channel extends EventEmitter {
           this.sendImmediately(send.method, send.fields);
         }
         return reply(null, f);
+      }
     }
   }
 }
diff --git a/lib/codec.js b/lib/codec.js
index 83fb6593..181fac2c 100644
--- a/lib/codec.js
+++ b/lib/codec.js
@@ -148,7 +148,8 @@ function encodeFieldValue(buffer, value, offset) {
   }
 
   switch (type) {
-    case 'string': // no shortstr in field tables
+    case 'string': {
+      // no shortstr in field tables
       const len = Buffer.byteLength(val, 'utf8');
       tag('S');
       buffer.writeUInt32BE(len, offset);
@@ -156,6 +157,7 @@ function encodeFieldValue(buffer, value, offset) {
       buffer.write(val, offset, 'utf8');
       offset += len;
       break;
+    }
     case 'object':
       if (val === null) {
         tag('V');
@@ -290,13 +292,15 @@ function decodeFields(slice) {
         val = slice.readUInt32BE(offset);
         offset += 4;
         break;
-      case 'D': // only positive decimals, apparently.
+      case 'D': {
+        // only positive decimals, apparently.
         const places = slice[offset];
         offset++;
         const digits = slice.readUInt32BE(offset);
         offset += 4;
         val = {'!': 'decimal', value: {places: places, digits: digits}};
         break;
+      }
       case 'T':
         val = ints.readUInt64BE(slice, offset);
         offset += 8;
diff --git a/lib/connection.js b/lib/connection.js
index f0f73216..032f6bf2 100644
--- a/lib/connection.js
+++ b/lib/connection.js
@@ -159,7 +159,7 @@ class Connection extends EventEmitter {
         case defs.ConnectionClose:
           bail(new Error(fmt('Handshake terminated by server: %s', closeMsg(reply))));
           break;
-        case defs.ConnectionTune:
+        case defs.ConnectionTune: {
           const fields = reply.fields;
           tunedOptions.frameMax = negotiate(fields.frameMax, allFields.frameMax);
           tunedOptions.channelMax = negotiate(fields.channelMax, allFields.channelMax);
@@ -173,6 +173,7 @@ class Connection extends EventEmitter {
           }
           expect(defs.ConnectionOpenOk, onOpenOk);
           break;
+        }
         default:
           bail(
             new Error(
diff --git a/test/codec.js b/test/codec.js
index b54c1074..805ee8d1 100644
--- a/test/codec.js
+++ b/test/codec.js
@@ -165,12 +165,13 @@ function removeExplicitTypes(input) {
         case 'decimal':
         case 'float':
           return input;
-        case undefined:
+        case undefined: {
           const newObj = {};
           for (const k in input) {
             newObj[k] = removeExplicitTypes(input[k]);
           }
           return newObj;
+        }
         default:
           return input.value;
       }