diff --git a/src/transaction_builder.js b/src/transaction_builder.js
index c299e29..e63bdd0 100644
--- a/src/transaction_builder.js
+++ b/src/transaction_builder.js
@@ -734,13 +734,20 @@ function checkSignArgs(inputs, signParams) {
       `Unknown prevOutScriptType "${signParams.prevOutScriptType}"`,
     );
   }
-  typeforce(
-    typeforce.tuple(
-      typeforce.Number,
-      typeforce.maybe(typeforce.Number),
-      types.Signer,
-    ),
-    [signParams.vin, signParams.hashType, signParams.keyPair],
+  tfMessage(
+    typeforce.Number,
+    signParams.vin,
+    `sign must include vin parameter as Number (input index)`,
+  );
+  tfMessage(
+    types.Signer,
+    signParams.keyPair,
+    `sign must include keyPair parameter as Signer interface`,
+  );
+  tfMessage(
+    typeforce.maybe(typeforce.Number),
+    signParams.hashType,
+    `sign hashType parameter must be a number`,
   );
   const prevOutType = (inputs[signParams.vin] || []).prevOutType;
   const posType = signParams.prevOutScriptType;
diff --git a/test/fixtures/transaction_builder.json b/test/fixtures/transaction_builder.json
index 040104a..07226b0 100644
--- a/test/fixtures/transaction_builder.json
+++ b/test/fixtures/transaction_builder.json
@@ -2470,6 +2470,190 @@
           }
         ]
       },
+      {
+        "exception": "input #0 is not of type p2pk: nulldata",
+        "inputs": [
+          {
+            "txId": "ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff",
+            "vout": 0,
+            "prevTxScript": "OP_RETURN deadbeef",
+            "signs": [
+              {
+                "prevOutScriptType": "p2pk",
+                "keyPair": "KzrA86mCVMGWnLGBQu9yzQa32qbxb5dvSK4XhyjjGAWSBKYX4rHx",
+                "throws": true
+              }
+            ]
+          }
+        ],
+        "outputs": [
+          {
+            "script": "OP_RETURN deadbeef",
+            "value": 1000
+          }
+        ]
+      },
+      {
+        "exception": "input #0 is not of type p2wpkh: nulldata",
+        "inputs": [
+          {
+            "txId": "ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff",
+            "vout": 0,
+            "prevTxScript": "OP_RETURN deadbeef",
+            "signs": [
+              {
+                "prevOutScriptType": "p2wpkh",
+                "keyPair": "KzrA86mCVMGWnLGBQu9yzQa32qbxb5dvSK4XhyjjGAWSBKYX4rHx",
+                "throws": true
+              }
+            ]
+          }
+        ],
+        "outputs": [
+          {
+            "script": "OP_RETURN deadbeef",
+            "value": 1000
+          }
+        ]
+      },
+      {
+        "exception": "input #0 is not of type p2ms: nulldata",
+        "inputs": [
+          {
+            "txId": "ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff",
+            "vout": 0,
+            "prevTxScript": "OP_RETURN deadbeef",
+            "signs": [
+              {
+                "prevOutScriptType": "p2ms",
+                "keyPair": "KzrA86mCVMGWnLGBQu9yzQa32qbxb5dvSK4XhyjjGAWSBKYX4rHx",
+                "throws": true
+              }
+            ]
+          }
+        ],
+        "outputs": [
+          {
+            "script": "OP_RETURN deadbeef",
+            "value": 1000
+          }
+        ]
+      },
+      {
+        "exception": "input #0 is not of type p2sh-p2wpkh: nulldata",
+        "inputs": [
+          {
+            "txId": "ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff",
+            "vout": 0,
+            "prevTxScript": "OP_RETURN deadbeef",
+            "signs": [
+              {
+                "prevOutScriptType": "p2sh-p2wpkh",
+                "keyPair": "KzrA86mCVMGWnLGBQu9yzQa32qbxb5dvSK4XhyjjGAWSBKYX4rHx",
+                "throws": true
+              }
+            ]
+          }
+        ],
+        "outputs": [
+          {
+            "script": "OP_RETURN deadbeef",
+            "value": 1000
+          }
+        ]
+      },
+      {
+        "exception": "input #0 is not of type p2sh-p2pk: nulldata",
+        "inputs": [
+          {
+            "txId": "ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff",
+            "vout": 0,
+            "prevTxScript": "OP_RETURN deadbeef",
+            "signs": [
+              {
+                "prevOutScriptType": "p2sh-p2pk",
+                "keyPair": "KzrA86mCVMGWnLGBQu9yzQa32qbxb5dvSK4XhyjjGAWSBKYX4rHx",
+                "throws": true
+              }
+            ]
+          }
+        ],
+        "outputs": [
+          {
+            "script": "OP_RETURN deadbeef",
+            "value": 1000
+          }
+        ]
+      },
+      {
+        "exception": "input #0 is not of type p2wsh-p2pk: nulldata",
+        "inputs": [
+          {
+            "txId": "ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff",
+            "vout": 0,
+            "prevTxScript": "OP_RETURN deadbeef",
+            "signs": [
+              {
+                "prevOutScriptType": "p2wsh-p2pk",
+                "keyPair": "KzrA86mCVMGWnLGBQu9yzQa32qbxb5dvSK4XhyjjGAWSBKYX4rHx",
+                "throws": true
+              }
+            ]
+          }
+        ],
+        "outputs": [
+          {
+            "script": "OP_RETURN deadbeef",
+            "value": 1000
+          }
+        ]
+      },
+      {
+        "exception": "input #0 is not of type p2sh-p2wsh-p2pk: nulldata",
+        "inputs": [
+          {
+            "txId": "ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff",
+            "vout": 0,
+            "prevTxScript": "OP_RETURN deadbeef",
+            "signs": [
+              {
+                "prevOutScriptType": "p2sh-p2wsh-p2pk",
+                "keyPair": "KzrA86mCVMGWnLGBQu9yzQa32qbxb5dvSK4XhyjjGAWSBKYX4rHx",
+                "throws": true
+              }
+            ]
+          }
+        ],
+        "outputs": [
+          {
+            "script": "OP_RETURN deadbeef",
+            "value": 1000
+          }
+        ]
+      },
+      {
+        "exception": "Unknown prevOutScriptType \"notvalidtype\"",
+        "inputs": [
+          {
+            "txId": "ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff",
+            "vout": 0,
+            "prevTxScript": "OP_RETURN deadbeef",
+            "signs": [
+              {
+                "prevOutScriptType": "notvalidtype",
+                "keyPair": "KzrA86mCVMGWnLGBQu9yzQa32qbxb5dvSK4XhyjjGAWSBKYX4rHx",
+                "throws": true
+              }
+            ]
+          }
+        ],
+        "outputs": [
+          {
+            "script": "OP_RETURN deadbeef",
+            "value": 1000
+          }
+        ]
+      },
       {
         "description": "Transaction w/ no outputs (but 1 SIGHASH_NONE)",
         "exception": "Transaction needs outputs",
diff --git a/test/transaction_builder.js b/test/transaction_builder.js
index fd6efa1..a135cca 100644
--- a/test/transaction_builder.js
+++ b/test/transaction_builder.js
@@ -104,7 +104,7 @@ function construct (f, dontSign, useOldSignArgs) {
 
 // TODO: Remove loop in v6
 for (const useOldSignArgs of [ false, true ]) {
-  // Search for "// TODO: Remove me in v6"
+  // Search for "useOldSignArgs"
   // to find the second part of this console.warn replace
   let consoleWarn;
   if (useOldSignArgs) {
@@ -426,6 +426,49 @@ for (const useOldSignArgs of [ false, true ]) {
         assert.strictEqual(txb.build().toHex(), '0100000001ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff010000006a473044022012a601efa8756ebe83e9ac7a7db061c3147e3b49d8be67685799fe51a4c8c62f02204d568d301d5ce14af390d566d4fd50e7b8ee48e71ec67786c029e721194dae3601210279be667ef9dcbbac55a06295ce870b07029bfcdb2dce28d959f2815b16f81798ffffffff01a0860100000000001976a914000000000000000000000000000000000000000088ac00000000')
       })
 
+      it('fails when missing required arguments', () => {
+        let txb = new TransactionBuilder()
+        txb.setVersion(1)
+        txb.addInput('ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff', 1)
+        txb.addOutput('1111111111111111111114oLvT2', 100000)
+        assert.throws(() => {
+          txb.sign()
+        }, /TransactionBuilder sign first arg must be TxbSignArg or number/)
+        assert.throws(() => {
+          txb.sign({
+            prevOutScriptType: 'p2pkh',
+            vin: 1,
+            keyPair,
+          })
+        }, /No input at index: 1/)
+        assert.throws(() => {
+          txb.sign({
+            prevOutScriptType: 'p2pkh',
+            keyPair,
+          })
+        }, /sign must include vin parameter as Number \(input index\)/)
+        assert.throws(() => {
+          txb.sign({
+            prevOutScriptType: 'p2pkh',
+            vin: 0,
+            keyPair: {},
+          })
+        }, /sign must include keyPair parameter as Signer interface/)
+        assert.throws(() => {
+          txb.sign({
+            prevOutScriptType: 'p2pkh',
+            vin: 0,
+            keyPair,
+            hashType: 'string',
+          })
+        }, /sign hashType parameter must be a number/)
+        if (useOldSignArgs) {
+          assert.throws(() => {
+            txb.sign(0)
+          }, /sign requires keypair/)
+        }
+      })
+
       fixtures.invalid.sign.forEach(f => {
         it('throws ' + f.exception + (f.description ? ' (' + f.description + ')' : ''), () => {
           const txb = construct(f, true)
diff --git a/ts_src/transaction_builder.ts b/ts_src/transaction_builder.ts
index 7d47ad3..c486285 100644
--- a/ts_src/transaction_builder.ts
+++ b/ts_src/transaction_builder.ts
@@ -958,13 +958,20 @@ function checkSignArgs(inputs: TxbInput[], signParams: TxbSignArg): void {
       `Unknown prevOutScriptType "${signParams.prevOutScriptType}"`,
     );
   }
-  typeforce(
-    typeforce.tuple(
-      typeforce.Number,
-      typeforce.maybe(typeforce.Number),
-      types.Signer,
-    ),
-    [signParams.vin, signParams.hashType, signParams.keyPair],
+  tfMessage(
+    typeforce.Number,
+    signParams.vin,
+    `sign must include vin parameter as Number (input index)`,
+  );
+  tfMessage(
+    types.Signer,
+    signParams.keyPair,
+    `sign must include keyPair parameter as Signer interface`,
+  );
+  tfMessage(
+    typeforce.maybe(typeforce.Number),
+    signParams.hashType,
+    `sign hashType parameter must be a number`,
   );
   const prevOutType = (inputs[signParams.vin] || []).prevOutType;
   const posType = signParams.prevOutScriptType;