diff --git a/.github/workflows/build.yaml b/.github/workflows/build.yaml
new file mode 100644
index 0000000..0002f49
--- /dev/null
+++ b/.github/workflows/build.yaml
@@ -0,0 +1,130 @@
+name: Build
+
+on:
+  push:
+    branches:
+      - main
+  pull_request:
+    branches:
+      - "*"
+
+jobs:
+  validate-remappings:
+    name: Validate remappings
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v6
+        with:
+          submodules: recursive
+
+      - name: Check all remapping targets exist
+        run: |
+          rc=0
+          for file in $(find . -name remappings.txt -not -path './lib/*' -not -path './node_modules/*'); do
+            dir=$(dirname "$file")
+            # Collect search bases: the remappings dir + libs from foundry.toml
+            bases="$dir"
+            if [ -f "$dir/foundry.toml" ]; then
+              for lib in $(grep "^libs" "$dir/foundry.toml" | sed "s/.*\[//;s/\].*//;s/'//g;s/\"//g;s/,/ /g"); do
+                bases="$bases $dir/$lib"
+              done
+            fi
+            while IFS= read -r line; do
+              [ -z "$line" ] && continue
+              target=$(echo "$line" | sed 's/.*=//')
+              found=false
+              for base in $bases; do
+                if [ -d "$base/$target" ]; then
+                  found=true
+                  break
+                fi
+              done
+              if [ "$found" = false ]; then
+                echo "::error file=$file::Broken remapping: $line (target '$target' not found)"
+                rc=1
+              fi
+            done < "$file"
+          done
+          exit $rc
+
+  foundry-root:
+    name: Compile root contracts (Foundry)
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v6
+        with:
+          submodules: recursive
+
+      - name: Install Foundry
+        uses: foundry-rs/foundry-toolchain@v1
+
+      - name: Run forge build
+        run: forge build
+
+  foundry-tests:
+    name: Compile ${{ matrix.standard }} test harness (Foundry)
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        standard: [ERC20, ERC721, ERC4626]
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v6
+        with:
+          submodules: recursive
+
+      - name: Install Foundry
+        uses: foundry-rs/foundry-toolchain@v1
+
+      - name: Run forge build
+        working-directory: tests/${{ matrix.standard }}/foundry
+        run: forge build
+
+  hardhat-root:
+    name: Compile root contracts (Hardhat)
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v6
+        with:
+          submodules: recursive
+
+      - name: Set up Node.js
+        uses: actions/setup-node@v6
+        with:
+          node-version: 22
+
+      - name: Install dependencies
+        run: npm install
+
+      - name: Run hardhat compile
+        run: npx hardhat compile
+
+  hardhat-tests:
+    name: Compile ${{ matrix.standard }} test harness (Hardhat)
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        standard: [ERC20, ERC721, ERC4626]
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v6
+        with:
+          submodules: recursive
+
+      - name: Set up Node.js
+        uses: actions/setup-node@v6
+        with:
+          node-version: 22
+
+      - name: Install dependencies
+        working-directory: tests/${{ matrix.standard }}/hardhat
+        run: npm install
+
+      - name: Run hardhat compile
+        working-directory: tests/${{ matrix.standard }}/hardhat
+        run: npx hardhat compile
diff --git a/.github/workflows/echidna.yaml b/.github/workflows/echidna.yaml
index 6839438..25db973 100644
--- a/.github/workflows/echidna.yaml
+++ b/.github/workflows/echidna.yaml
@@ -8,9 +8,6 @@ on:
     branches:
       - "*"
 
-env:
-  FOUNDRY_PROFILE: ci
-
 jobs:
   foundry:
     name: Test Foundry examples
diff --git a/.github/workflows/medusa.yaml b/.github/workflows/medusa.yaml
index 5635b32..97f9c89 100644
--- a/.github/workflows/medusa.yaml
+++ b/.github/workflows/medusa.yaml
@@ -8,9 +8,6 @@ on:
     branches:
       - "*"
 
-env:
-  FOUNDRY_PROFILE: ci
-
 jobs:
   foundry:
     name: Test Foundry examples
@@ -52,6 +49,20 @@ jobs:
         run: |
           medusa fuzz --target-contracts CryticERC20ExternalHarness --config medusa-config-ext.json
 
+      - name: Compile ERC721 Foundry example
+        working-directory: tests/ERC721/foundry
+        run: forge build --build-info
+
+      - name: Run Medusa for Internal ERC721 tests
+        working-directory: tests/ERC721/foundry
+        run: |
+          medusa fuzz --target-contracts CryticERC721InternalHarness --config medusa-config.json
+
+      - name: Run Medusa for External ERC721 tests
+        working-directory: tests/ERC721/foundry
+        run: |
+          medusa fuzz --target-contracts CryticERC721ExternalHarness --config medusa-config-ext.json
+
       - name: Compile ERC4626 Foundry example
         working-directory: tests/ERC4626/foundry
         run: forge build --build-info
diff --git a/tests/ERC721/foundry/medusa-config-ext.json b/tests/ERC721/foundry/medusa-config-ext.json
new file mode 100644
index 0000000..0acd176
--- /dev/null
+++ b/tests/ERC721/foundry/medusa-config-ext.json
@@ -0,0 +1,80 @@
+{
+	"fuzzing": {
+		"workers": 10,
+		"workerResetLimit": 50,
+		"timeout": 0,
+		"testLimit": 500000,
+		"callSequenceLength": 100,
+		"corpusDirectory": "tests/medusa-corpus-ext",
+		"coverageEnabled": true,
+		"targetContracts": [],
+		"targetContractsBalances": [],
+		"constructorArgs": {},
+		"deployerAddress": "0x10000",
+		"senderAddresses": [
+			"0x10000",
+			"0x20000",
+			"0x30000"
+		],
+		"blockNumberDelayMax": 60480,
+		"blockTimestampDelayMax": 604800,
+		"blockGasLimit": 125000000,
+		"transactionGasLimit": 12500000,
+		"testing": {
+			"stopOnFailedTest": true,
+			"stopOnFailedContractMatching": false,
+			"stopOnNoTests": true,
+			"testAllContracts": true,
+			"traceAll": false,
+			"assertionTesting": {
+				"enabled": true,
+				"testViewMethods": false,
+				"panicCodeConfig": {
+					"failOnCompilerInsertedPanic": false,
+					"failOnAssertion": true,
+					"failOnArithmeticUnderflow": false,
+					"failOnDivideByZero": false,
+					"failOnEnumTypeConversionOutOfBounds": false,
+					"failOnIncorrectStorageAccess": false,
+					"failOnPopEmptyArray": false,
+					"failOnOutOfBoundsArrayAccess": false,
+					"failOnAllocateTooMuchMemory": false,
+					"failOnCallUninitializedVariable": false
+				}
+			},
+			"propertyTesting": {
+				"enabled": false,
+				"testPrefixes": [
+					"property_"
+				]
+			},
+			"optimizationTesting": {
+				"enabled": false,
+				"testPrefixes": [
+					"optimize_"
+				]
+			}
+		},
+		"chainConfig": {
+			"codeSizeCheckDisabled": true,
+			"cheatCodes": {
+				"cheatCodesEnabled": true,
+				"enableFFI": false
+			}
+		}
+	},
+	"compilation": {
+		"platform": "crytic-compile",
+		"platformConfig": {
+			"target": ".",
+			"solcVersion": "",
+			"exportDirectory": "",
+			"args": ["--foundry-compile-all"]
+		}
+	},
+	"logging": {
+		"level": "info",
+		"logDirectory": "",
+		"noColor": false
+	}
+}
diff --git a/tests/ERC721/foundry/medusa-config.json b/tests/ERC721/foundry/medusa-config.json
new file mode 100644
index 0000000..d5a8b5b
--- /dev/null
+++ b/tests/ERC721/foundry/medusa-config.json
@@ -0,0 +1,80 @@
+{
+	"fuzzing": {
+		"workers": 10,
+		"workerResetLimit": 50,
+		"timeout": 0,
+		"testLimit": 500000,
+		"callSequenceLength": 100,
+		"corpusDirectory": "tests/medusa-corpus",
+		"coverageEnabled": true,
+		"targetContracts": [],
+		"targetContractsBalances": [],
+		"constructorArgs": {},
+		"deployerAddress": "0x10000",
+		"senderAddresses": [
+			"0x10000",
+			"0x20000",
+			"0x30000"
+		],
+		"blockNumberDelayMax": 60480,
+		"blockTimestampDelayMax": 604800,
+		"blockGasLimit": 125000000,
+		"transactionGasLimit": 12500000,
+		"testing": {
+			"stopOnFailedTest": true,
+			"stopOnFailedContractMatching": true,
+			"stopOnNoTests": true,
+			"testAllContracts": false,
+			"traceAll": false,
+			"assertionTesting": {
+				"enabled": true,
+				"testViewMethods": false,
+				"panicCodeConfig": {
+					"failOnCompilerInsertedPanic": false,
+					"failOnAssertion": true,
+					"failOnArithmeticUnderflow": false,
+					"failOnDivideByZero": false,
+					"failOnEnumTypeConversionOutOfBounds": false,
+					"failOnIncorrectStorageAccess": false,
+					"failOnPopEmptyArray": false,
+					"failOnOutOfBoundsArrayAccess": false,
+					"failOnAllocateTooMuchMemory": false,
+					"failOnCallUninitializedVariable": false
+				}
+			},
+			"propertyTesting": {
+				"enabled": false,
+				"testPrefixes": [
+					"property_"
+				]
+			},
+			"optimizationTesting": {
+				"enabled": false,
+				"testPrefixes": [
+					"optimize_"
+				]
+			}
+		},
+		"chainConfig": {
+			"codeSizeCheckDisabled": true,
+			"cheatCodes": {
+				"cheatCodesEnabled": true,
+				"enableFFI": false
+			}
+		}
+	},
+	"compilation": {
+		"platform": "crytic-compile",
+		"platformConfig": {
+			"target": ".",
+			"solcVersion": "",
+			"exportDirectory": "",
+			"args": ["--foundry-compile-all"]
+		}
+	},
+	"logging": {
+		"level": "info",
+		"logDirectory": "",
+		"noColor": false
+	}
+}