diff --git a/.github/workflows/full-dev-path.yml b/.github/workflows/aztec-cli-acceptance-test.yml
similarity index 51%
rename from .github/workflows/full-dev-path.yml
rename to .github/workflows/aztec-cli-acceptance-test.yml
index 5eee9fa514a0..89b55e912252 100644
--- a/.github/workflows/full-dev-path.yml
+++ b/.github/workflows/aztec-cli-acceptance-test.yml
@@ -1,6 +1,6 @@
-# Tests that the installed Aztec toolchain works end-to-end.
-# Exercises the full developer onboarding path: aztec init -> compile -> test -> start -> codegen -> TS end-to-end test.
-name: Full Dev Path Test
+# Validates that a published Aztec CLI release can be installed and used end-to-end.
+# Runs after CI3 completes a tag release (via workflow_run), or manually via workflow_dispatch.
+name: Aztec CLI Acceptance Test
 
 on:
   workflow_dispatch:
@@ -9,22 +9,30 @@ on:
         description: "Version to install (e.g. latest, nightly, 4.3.0, 4.3.0-nightly.20260420)"
         required: true
         type: string
-  push:
-    tags:
+  workflow_run:
+    workflows: ["CI3"]
+    types:
+      - completed
+    branches:
       - "v*"
 
 jobs:
-  full-dev-path:
+  release-acceptance:
     runs-on: ubuntu-latest
+    if: >-
+      github.event_name == 'workflow_dispatch' ||
+      (github.event_name == 'workflow_run' && github.event.workflow_run.conclusion == 'success')
     timeout-minutes: 30
     env:
-      VERSION: ${{ github.event.inputs.version || github.ref_name }}
+      VERSION: ${{ github.event.inputs.version || github.event.workflow_run.head_branch }}
     steps:
       - name: Checkout
         uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683
+        with:
+          ref: ${{ github.event.workflow_run.head_sha || github.sha }}
 
-      - name: Run full dev path test
-        run: ./aztec-up/test/full-dev-path/run-test.sh
+      - name: Run Aztec CLI acceptance test
+        run: ./aztec-up/test/aztec-cli-acceptance-test/run-test.sh
 
       - name: Notify Slack on success
         if: success() && github.event_name != 'workflow_dispatch'
@@ -33,7 +41,7 @@ jobs:
         run: |
           export CI=1
           ./ci3/slack_notify "#team-fairies" \
-            "Full Dev Path Test passed for version ${VERSION} :white_check_mark:"
+            "Aztec CLI Acceptance Test passed for version ${VERSION} :white_check_mark:"
 
       - name: Notify Slack and dispatch ClaudeBox on failure
         if: failure() && github.event_name != 'workflow_dispatch'
@@ -44,6 +52,6 @@ jobs:
           RUN_URL="https://github.com/${{ github.repository }}/actions/runs/${{ github.run_id }}"
           export CI=1
           ./ci3/slack_notify_with_claudebox_kickoff "#team-fairies" \
-            "Full Dev Path Test FAILED (version ${VERSION}): <${RUN_URL}|View Run>" \
-            "Full dev path test failed for version ${VERSION}. CI run: ${RUN_URL}. Investigate the failure and explain the root cause." \
+            "Aztec CLI Acceptance Test FAILED (version ${VERSION}): <${RUN_URL}|View Run>" \
+            "Aztec CLI acceptance test failed for version ${VERSION}. CI run: ${RUN_URL}. Investigate the failure and explain the root cause." \
             --link "$RUN_URL"
diff --git a/aztec-up/bin/0.0.1/install b/aztec-up/bin/0.0.1/install
index 9d5b3f500871..5f56b6ef123f 100755
--- a/aztec-up/bin/0.0.1/install
+++ b/aztec-up/bin/0.0.1/install
@@ -173,11 +173,14 @@ function install_foundry {
   temp_foundry_dir=$(mktemp -d) || { echo "Error: Failed to create temp directory" >&2; exit 1; }
   mkdir -p "$temp_foundry_dir/bin"
 
-  # Always install/update foundryup
-  curl --max-time 30 -L https://foundry.paradigm.xyz | bash
+  # The foundry installer defaults to $XDG_CONFIG_HOME/.foundry when that var is set, which
+  # puts foundryup somewhere we don't expect. We'll pin FOUNDRY_DIR so we control the install
+  # location regardless of the caller's environment.
+  local foundry_home="$HOME/.foundry"
+  FOUNDRY_DIR="$foundry_home" curl --max-time 30 -L https://foundry.paradigm.xyz | FOUNDRY_DIR="$foundry_home" bash
 
   # Install foundry to temp location and move to version directory
-  FOUNDRY_DIR="$temp_foundry_dir" timeout 30 "$HOME/.foundry/bin/foundryup" -i "$foundry_version"
+  FOUNDRY_DIR="$temp_foundry_dir" timeout 30 "$foundry_home/bin/foundryup" -i "$foundry_version"
 
   # Move the foundry binaries to our version bin directory
   for binary in forge cast anvil chisel; do
diff --git a/aztec-up/test/full-dev-path/README.md b/aztec-up/test/aztec-cli-acceptance-test/README.md
similarity index 68%
rename from aztec-up/test/full-dev-path/README.md
rename to aztec-up/test/aztec-cli-acceptance-test/README.md
index fa3ef2896770..f37c307d6418 100644
--- a/aztec-up/test/full-dev-path/README.md
+++ b/aztec-up/test/aztec-cli-acceptance-test/README.md
@@ -1,6 +1,6 @@
-# Full Dev Path Test
+# Aztec CLI Acceptance Test
 
-Tests that the installed Aztec toolchain works end-to-end. Exercises the complete developer onboarding path:
+Tests that the installed Aztec CLI toolchain works end-to-end. Exercises the complete developer onboarding path:
 
 1. `aztec init` - scaffold a new workspace with a Counter contract and test crate
 2. `aztec compile` - compile the scaffolded contract
@@ -30,6 +30,6 @@ VERSION=4.3.0 ./run-test.sh
 
 ## Architecture
 
-- **`run-test.sh`** - Bash launcher. Runs the aztec installer (unless skipped), sets up PATH, then `exec node full-dev-path.ts`.
-- **`full-dev-path.ts`** - Orchestrator. Runs each CLI step against the installed toolchain and, after codegen, copies `counter.test.ts` into the scaffolded workspace and spawns `node --test` on it. Each phase is wrapped in `step(name, fn)` so failures clearly identify which step broke. Always emits a machine-readable result line for CI/Slack integration: `TEST_RESULT=pass version=...` on success, or `TEST_RESULT=fail step=... version=... error="..."` on failure (with a full banner printed above it).
+- **`run-test.sh`** - Bash launcher. Runs the aztec installer (unless skipped), sets up PATH, then `exec node aztec-cli-acceptance-test.ts`.
+- **`aztec-cli-acceptance-test.ts`** - Orchestrator. Runs each CLI step against the installed toolchain and, after codegen, copies `counter.test.ts` into the scaffolded workspace and spawns `node --test` on it. Each phase is wrapped in `step(name, fn)` so failures clearly identify which step broke. Always emits a machine-readable result line for CI/Slack integration: `TEST_RESULT=pass version=...` on success, or `TEST_RESULT=fail step=... version=... error="..."` on failure (with a full banner printed above it).
 - **`counter.test.ts`** - The `node:test` suite that drives the deployed Counter end-to-end through the codegen'd bindings. Lives here as a template; copied into the workspace at test time so it can statically `import { CounterContract } from './artifacts/Counter.js'` with real codegen types and resolve `@aztec/*` via the workspace's `node_modules` symlink to the install.
diff --git a/aztec-up/test/full-dev-path/full-dev-path.ts b/aztec-up/test/aztec-cli-acceptance-test/aztec-cli-acceptance-test.ts
similarity index 98%
rename from aztec-up/test/full-dev-path/full-dev-path.ts
rename to aztec-up/test/aztec-cli-acceptance-test/aztec-cli-acceptance-test.ts
index 93c7eaa8fb0c..adffe0dde3a6 100644
--- a/aztec-up/test/full-dev-path/full-dev-path.ts
+++ b/aztec-up/test/aztec-cli-acceptance-test/aztec-cli-acceptance-test.ts
@@ -45,7 +45,7 @@ if (!existsSync(join(AZTEC_INSTALL_DIR, 'package.json'))) {
   process.exit(2);
 }
 
-const TMP_DIR = mkdtempSync(join(tmpdir(), 'aztec-full-dev-path-'));
+const TMP_DIR = mkdtempSync(join(tmpdir(), 'aztec-cli-acceptance-test-'));
 const WORKSPACE_DIR = join(TMP_DIR, 'my_workspace');
 
 // Exit codes follow the Unix 128+signal convention for signal terminations.
@@ -231,7 +231,7 @@ function reportFailure(stepName: string, aztecVersion: string, err: unknown) {
   const banner = '='.repeat(72);
 
   console.error(`\n${banner}`);
-  console.error('FULL DEV PATH TEST FAILED');
+  console.error('AZTEC CLI ACCEPTANCE TEST FAILED');
   console.error(banner);
   console.error(`Step:        ${stepName}`);
   console.error(`Version:     ${aztecVersion}`);
diff --git a/aztec-up/test/full-dev-path/counter.test.ts b/aztec-up/test/aztec-cli-acceptance-test/counter.test.ts
similarity index 100%
rename from aztec-up/test/full-dev-path/counter.test.ts
rename to aztec-up/test/aztec-cli-acceptance-test/counter.test.ts
diff --git a/aztec-up/test/full-dev-path/run-test.sh b/aztec-up/test/aztec-cli-acceptance-test/run-test.sh
similarity index 87%
rename from aztec-up/test/full-dev-path/run-test.sh
rename to aztec-up/test/aztec-cli-acceptance-test/run-test.sh
index 52e79d56a2a9..2ea5413c43fd 100755
--- a/aztec-up/test/full-dev-path/run-test.sh
+++ b/aztec-up/test/aztec-cli-acceptance-test/run-test.sh
@@ -1,10 +1,10 @@
 #!/usr/bin/env bash
-# Launcher for the full-dev-path test.
+# Launcher for the Aztec CLI acceptance test.
 #
 # Steps:
 #   1. Install Node via NVM if not present (skipped with SKIP_INSTALL=1)
 #   2. Install the Aztec toolchain via the public installer (skipped with SKIP_INSTALL=1)
-#   3. Run full-dev-path.ts which exercises the installed toolchain end-to-end
+#   3. Run aztec-cli-acceptance-test.ts which exercises the installed toolchain end-to-end
 #
 # Env vars:
 #   SKIP_INSTALL=1      Skip steps 1-2 and use the already-installed toolchain (dev-box inner loop).
@@ -37,4 +37,4 @@ export PATH="$HOME/.aztec/current/bin:$HOME/.aztec/bin:$PATH"
 export AZTEC_INSTALL_DIR="${AZTEC_INSTALL_DIR:-$HOME/.aztec/current}"
 
 echo ">>> Running test"
-exec node --no-warnings "${script_dir}/full-dev-path.ts"
+exec node --no-warnings "${script_dir}/aztec-cli-acceptance-test.ts"
diff --git a/noir-projects/aztec-nr/aztec/src/authwit/entrypoint/app.nr b/noir-projects/aztec-nr/aztec/src/authwit/entrypoint/app.nr
index 9af791d5b148..20835a9c6dbd 100644
--- a/noir-projects/aztec-nr/aztec/src/authwit/entrypoint/app.nr
+++ b/noir-projects/aztec-nr/aztec/src/authwit/entrypoint/app.nr
@@ -2,7 +2,7 @@ use crate::{authwit::entrypoint::FunctionCall, context::PrivateContext};
 use crate::protocol::{
     constants::DOM_SEP__SIGNATURE_PAYLOAD,
     hash::poseidon2_hash_with_separator,
-    traits::{Hash, Serialize},
+    traits::{Deserialize, Hash, Serialize},
 };
 use std::meta::derive;
 
@@ -12,7 +12,7 @@ global ACCOUNT_MAX_CALLS: u32 = 5;
 // - default_entrypoint.ts
 // - account_entrypoint.ts (specifically `getEntrypointAbi()`)
 // - default_multi_call_entrypoint.ts (specifically `getEntrypointAbi()`)
-#[derive(Serialize)]
+#[derive(Deserialize, Serialize)]
 pub struct AppPayload {
     function_calls: [FunctionCall; ACCOUNT_MAX_CALLS],
     // A nonce that enables transaction cancellation. When the cancellable flag is enabled, this nonce is used to
diff --git a/noir-projects/aztec-nr/aztec/src/authwit/entrypoint/function_call.nr b/noir-projects/aztec-nr/aztec/src/authwit/entrypoint/function_call.nr
index 7bc365f5b3b4..6a79f9f67176 100644
--- a/noir-projects/aztec-nr/aztec/src/authwit/entrypoint/function_call.nr
+++ b/noir-projects/aztec-nr/aztec/src/authwit/entrypoint/function_call.nr
@@ -1,4 +1,8 @@
-use crate::protocol::{abis::function_selector::FunctionSelector, address::AztecAddress, traits::Serialize};
+use crate::protocol::{
+    abis::function_selector::FunctionSelector,
+    address::AztecAddress,
+    traits::{Deserialize, Serialize},
+};
 use std::meta::derive;
 
 // @dev: If you change the following struct you have to update:
@@ -6,7 +10,7 @@ use std::meta::derive;
 // - default_multi_call_entrypoint.ts (specifically `getEntrypointAbi()`)
 // - function_call.ts
 // - encoding.ts
-#[derive(Serialize)]
+#[derive(Deserialize, Serialize)]
 pub struct FunctionCall {
     // args_hash is calldata_hash if is_public is true
     pub args_hash: Field,
diff --git a/noir-projects/aztec-nr/aztec/src/macros/functions/mod.nr b/noir-projects/aztec-nr/aztec/src/macros/functions/mod.nr
index ab345e9c31e2..57639f879feb 100644
--- a/noir-projects/aztec-nr/aztec/src/macros/functions/mod.nr
+++ b/noir-projects/aztec-nr/aztec/src/macros/functions/mod.nr
@@ -5,7 +5,7 @@ pub(crate) mod auth_registry;
 
 use crate::macros::{
     internals_functions_generation::{external_functions_registry, internal_functions_registry},
-    utils::{is_fn_external, module_has_initializer},
+    utils::{assert_params_serializable, assert_return_type_serializable, is_fn_external, module_has_initializer},
 };
 use super::utils::{fn_has_allow_phase_change, fn_has_noinitcheck, is_fn_initializer, is_fn_only_self, is_fn_view};
 use auth_registry::AUTHORIZE_ONCE_REGISTRY;
@@ -342,6 +342,9 @@ pub comptime fn external(f: FunctionDefinition, f_type: CtString) {
     // In this function we perform basic checks on the function to ensure it is valid and then we add the function to
     // the external functions registry for later processing by the `#[aztec]` macro.
 
+    assert_return_type_serializable(f);
+    assert_params_serializable(f);
+
     if f_type.eq("private") {
         assert_valid_private(f);
         external_functions_registry::add_private(f);
diff --git a/noir-projects/aztec-nr/aztec/src/macros/utils.nr b/noir-projects/aztec-nr/aztec/src/macros/utils.nr
index e806693421ae..fcd2852853fb 100644
--- a/noir-projects/aztec-nr/aztec/src/macros/utils.nr
+++ b/noir-projects/aztec-nr/aztec/src/macros/utils.nr
@@ -1,5 +1,5 @@
 use crate::protocol::meta::derive_serialize;
-use std::meta::{ctstring::AsCtString, unquote};
+use std::meta::{ctstring::AsCtString, type_of, unquote};
 
 pub(crate) comptime fn is_fn_external(f: FunctionDefinition) -> bool {
     f.has_named_attribute("external")
@@ -153,6 +153,44 @@ pub(crate) comptime fn get_trait_impl_method(typ: Type, target_trait: Quoted, ta
         .as_typed_expr()
 }
 
+/// Asserts that the return type of a contract function implements both `Serialize` and `Deserialize`.
+/// Functions with a `()` return type are skipped since unit values are not serialized.
+pub(crate) comptime fn assert_return_type_serializable(f: FunctionDefinition) {
+    let return_type = f.return_type();
+    if return_type != type_of(()) {
+        let fn_name = f.name();
+        let serialize_constraint = quote { crate::protocol::traits::Serialize }.as_trait_constraint();
+        assert(
+            return_type.implements(serialize_constraint),
+            f"Contract function '{fn_name}' returns a value of type {return_type}, which does not implement the Serialize trait. Add #[derive(Serialize)] to {return_type}'s declaration.",
+        );
+        let deserialize_constraint = quote { crate::protocol::traits::Deserialize }.as_trait_constraint();
+        assert(
+            return_type.implements(deserialize_constraint),
+            f"Contract function '{fn_name}' returns a value of type {return_type}, which does not implement the Deserialize trait. Add #[derive(Deserialize)] to {return_type}'s declaration.",
+        );
+    }
+}
+
+/// Asserts that all parameters of a contract function implement both `Serialize` and `Deserialize`.
+pub(crate) comptime fn assert_params_serializable(f: FunctionDefinition) {
+    let fn_name = f.name();
+
+    for param in f.parameters() {
+        let (name, param_type) = param;
+        let serialize_constraint = quote { crate::protocol::traits::Serialize }.as_trait_constraint();
+        assert(
+            param_type.implements(serialize_constraint),
+            f"Parameter '{name}' of contract function '{fn_name}' has type {param_type}, which does not implement the Serialize trait. Add #[derive(Serialize)] to {param_type}'s declaration.",
+        );
+        let deserialize_constraint = quote { crate::protocol::traits::Deserialize }.as_trait_constraint();
+        assert(
+            param_type.implements(deserialize_constraint),
+            f"Parameter '{name}' of contract function '{fn_name}' has type {param_type}, which does not implement the Deserialize trait. Add #[derive(Deserialize)] to {param_type}'s declaration.",
+        );
+    }
+}
+
 /// Generates a quote that implements `Serialize` for a given struct `s`. If the struct already implements `Serialize`,
 /// we return an empty quote.
 pub comptime fn derive_serialize_if_not_implemented(s: TypeDefinition) -> Quoted {
diff --git a/noir-projects/noir-contracts-comp-failures/contracts/non_deserializable/Nargo.toml b/noir-projects/noir-contracts-comp-failures/contracts/non_deserializable/Nargo.toml
new file mode 100644
index 000000000000..5914769cb4d6
--- /dev/null
+++ b/noir-projects/noir-contracts-comp-failures/contracts/non_deserializable/Nargo.toml
@@ -0,0 +1,8 @@
+[package]
+name = "non_deserializable"
+authors = [""]
+compiler_version = ">=0.25.0"
+type = "contract"
+
+[dependencies]
+aztec = { path = "../../../aztec-nr/aztec" }
diff --git a/noir-projects/noir-contracts-comp-failures/contracts/non_deserializable/expected_error b/noir-projects/noir-contracts-comp-failures/contracts/non_deserializable/expected_error
new file mode 100644
index 000000000000..0752e0c1a17f
--- /dev/null
+++ b/noir-projects/noir-contracts-comp-failures/contracts/non_deserializable/expected_error
@@ -0,0 +1,6 @@
+Contract function 'bad_private_return' returns a value of type NotDeserializable, which does not implement the Deserialize trait. Add #[derive(Deserialize)] to NotDeserializable's declaration.
+Parameter '_p' of contract function 'bad_private_param' has type NotDeserializable, which does not implement the Deserialize trait. Add #[derive(Deserialize)] to NotDeserializable's declaration.
+Contract function 'bad_public_return' returns a value of type NotDeserializable, which does not implement the Deserialize trait. Add #[derive(Deserialize)] to NotDeserializable's declaration.
+Parameter '_p' of contract function 'bad_public_param' has type NotDeserializable, which does not implement the Deserialize trait. Add #[derive(Deserialize)] to NotDeserializable's declaration.
+Contract function 'bad_utility_return' returns a value of type NotDeserializable, which does not implement the Deserialize trait. Add #[derive(Deserialize)] to NotDeserializable's declaration.
+Parameter '_p' of contract function 'bad_utility_param' has type NotDeserializable, which does not implement the Deserialize trait. Add #[derive(Deserialize)] to NotDeserializable's declaration.
diff --git a/noir-projects/noir-contracts-comp-failures/contracts/non_deserializable/src/main.nr b/noir-projects/noir-contracts-comp-failures/contracts/non_deserializable/src/main.nr
new file mode 100644
index 000000000000..87dd42cdd870
--- /dev/null
+++ b/noir-projects/noir-contracts-comp-failures/contracts/non_deserializable/src/main.nr
@@ -0,0 +1,38 @@
+// Tests that contract functions using a type that does not implement Deserialize fail to compile, for all function types
+// (private, public, utility) and both return types and parameters.
+use aztec::macros::aztec;
+
+#[aztec]
+pub contract NonDeserializable {
+    use aztec::macros::functions::external;
+    use aztec::protocol::traits::Serialize;
+
+    #[derive(Serialize)]
+    pub struct NotDeserializable {
+        x: Field,
+    }
+
+    #[external("private")]
+    fn bad_private_return() -> pub NotDeserializable {
+        NotDeserializable { x: 1 }
+    }
+
+    #[external("private")]
+    fn bad_private_param(_p: NotDeserializable) {}
+
+    #[external("public")]
+    fn bad_public_return() -> pub NotDeserializable {
+        NotDeserializable { x: 1 }
+    }
+
+    #[external("public")]
+    fn bad_public_param(_p: NotDeserializable) {}
+
+    #[external("utility")]
+    unconstrained fn bad_utility_return() -> pub NotDeserializable {
+        NotDeserializable { x: 1 }
+    }
+
+    #[external("utility")]
+    unconstrained fn bad_utility_param(_p: NotDeserializable) {}
+}
diff --git a/noir-projects/noir-contracts-comp-failures/contracts/non_serializable/Nargo.toml b/noir-projects/noir-contracts-comp-failures/contracts/non_serializable/Nargo.toml
new file mode 100644
index 000000000000..61dd673b2bd3
--- /dev/null
+++ b/noir-projects/noir-contracts-comp-failures/contracts/non_serializable/Nargo.toml
@@ -0,0 +1,8 @@
+[package]
+name = "non_serializable"
+authors = [""]
+compiler_version = ">=0.25.0"
+type = "contract"
+
+[dependencies]
+aztec = { path = "../../../aztec-nr/aztec" }
diff --git a/noir-projects/noir-contracts-comp-failures/contracts/non_serializable/expected_error b/noir-projects/noir-contracts-comp-failures/contracts/non_serializable/expected_error
new file mode 100644
index 000000000000..33a63c051f3a
--- /dev/null
+++ b/noir-projects/noir-contracts-comp-failures/contracts/non_serializable/expected_error
@@ -0,0 +1,6 @@
+Contract function 'bad_private_return' returns a value of type NotSerializable, which does not implement the Serialize trait. Add #[derive(Serialize)] to NotSerializable's declaration.
+Parameter '_p' of contract function 'bad_private_param' has type NotSerializable, which does not implement the Serialize trait. Add #[derive(Serialize)] to NotSerializable's declaration.
+Contract function 'bad_public_return' returns a value of type NotSerializable, which does not implement the Serialize trait. Add #[derive(Serialize)] to NotSerializable's declaration.
+Parameter '_p' of contract function 'bad_public_param' has type NotSerializable, which does not implement the Serialize trait. Add #[derive(Serialize)] to NotSerializable's declaration.
+Contract function 'bad_utility_return' returns a value of type NotSerializable, which does not implement the Serialize trait. Add #[derive(Serialize)] to NotSerializable's declaration.
+Parameter '_p' of contract function 'bad_utility_param' has type NotSerializable, which does not implement the Serialize trait. Add #[derive(Serialize)] to NotSerializable's declaration.
diff --git a/noir-projects/noir-contracts-comp-failures/contracts/non_serializable/src/main.nr b/noir-projects/noir-contracts-comp-failures/contracts/non_serializable/src/main.nr
new file mode 100644
index 000000000000..b59ba8578653
--- /dev/null
+++ b/noir-projects/noir-contracts-comp-failures/contracts/non_serializable/src/main.nr
@@ -0,0 +1,38 @@
+// Tests that contract functions using a type that does not implement Serialize fail to compile, for all function types
+// (private, public, utility) and both return types and parameters.
+use aztec::macros::aztec;
+
+#[aztec]
+pub contract NonSerializable {
+    use aztec::macros::functions::external;
+    use aztec::protocol::traits::Deserialize;
+
+    #[derive(Deserialize)]
+    pub struct NotSerializable {
+        x: Field,
+    }
+
+    #[external("private")]
+    fn bad_private_return() -> pub NotSerializable {
+        NotSerializable { x: 1 }
+    }
+
+    #[external("private")]
+    fn bad_private_param(_p: NotSerializable) {}
+
+    #[external("public")]
+    fn bad_public_return() -> pub NotSerializable {
+        NotSerializable { x: 1 }
+    }
+
+    #[external("public")]
+    fn bad_public_param(_p: NotSerializable) {}
+
+    #[external("utility")]
+    unconstrained fn bad_utility_return() -> pub NotSerializable {
+        NotSerializable { x: 1 }
+    }
+
+    #[external("utility")]
+    unconstrained fn bad_utility_param(_p: NotSerializable) {}
+}
diff --git a/noir-projects/noir-contracts/Nargo.toml b/noir-projects/noir-contracts/Nargo.toml
index 6e22013335f9..61718afd5350 100644
--- a/noir-projects/noir-contracts/Nargo.toml
+++ b/noir-projects/noir-contracts/Nargo.toml
@@ -77,6 +77,7 @@ members = [
     "contracts/test/storage_proof_test_contract",
     "contracts/test/test_contract",
     "contracts/test/test_log_contract",
+    "contracts/test/unit_return_type_contract",
     "contracts/test/updatable_contract",
     "contracts/test/updated_contract"
 ]
diff --git a/noir-projects/noir-contracts/contracts/app/app_subscription_contract/src/dapp_payload.nr b/noir-projects/noir-contracts/contracts/app/app_subscription_contract/src/dapp_payload.nr
index 69d31c7a7dbf..ddfca613a786 100644
--- a/noir-projects/noir-contracts/contracts/app/app_subscription_contract/src/dapp_payload.nr
+++ b/noir-projects/noir-contracts/contracts/app/app_subscription_contract/src/dapp_payload.nr
@@ -5,7 +5,7 @@ use aztec::{
         address::AztecAddress,
         constants::DOM_SEP__SIGNATURE_PAYLOAD,
         hash::poseidon2_hash_with_separator,
-        traits::{Hash, Serialize},
+        traits::{Deserialize, Hash, Serialize},
     },
 };
 use std::meta::derive;
@@ -13,7 +13,7 @@ use std::meta::derive;
 global DAPP_MAX_CALLS: u32 = 1;
 
 // @dev: If you change the following struct you have to update default_entrypoint.ts
-#[derive(Serialize)]
+#[derive(Deserialize, Serialize)]
 pub struct DAppPayload {
     function_calls: [FunctionCall; DAPP_MAX_CALLS],
     // A nonce that enables transaction cancellation. When the cancellable flag is enabled, this nonce is used to
diff --git a/noir-projects/noir-contracts/contracts/app/card_game_contract/src/cards.nr b/noir-projects/noir-contracts/contracts/app/card_game_contract/src/cards.nr
index d7cb22c0edfe..7472b6570b30 100644
--- a/noir-projects/noir-contracts/contracts/app/card_game_contract/src/cards.nr
+++ b/noir-projects/noir-contracts/contracts/app/card_game_contract/src/cards.nr
@@ -9,14 +9,14 @@ use aztec::{
     protocol::{
         address::AztecAddress,
         constants::MAX_NOTE_HASH_READ_REQUESTS_PER_CALL,
-        traits::{FromField, Hash, Packable, Serialize, ToField},
+        traits::{Deserialize, FromField, Hash, Packable, Serialize, ToField},
     },
     state_vars::{Owned, PrivateSet, StateVariable},
 };
 use field_note::FieldNote;
 use std::meta::derive;
 
-#[derive(Serialize)]
+#[derive(Serialize, Deserialize)]
 pub struct Card {
     // We use u32s since u16s are unsupported
     pub strength: u32,
diff --git a/noir-projects/noir-contracts/contracts/app/card_game_contract/src/game.nr b/noir-projects/noir-contracts/contracts/app/card_game_contract/src/game.nr
index ea1bbd90104d..7330fd228be1 100644
--- a/noir-projects/noir-contracts/contracts/app/card_game_contract/src/game.nr
+++ b/noir-projects/noir-contracts/contracts/app/card_game_contract/src/game.nr
@@ -1,11 +1,14 @@
 use crate::cards::Card;
-use aztec::protocol::{address::AztecAddress, traits::{Deserialize, FromField, Packable, ToField}};
+use aztec::protocol::{
+    address::AztecAddress,
+    traits::{Deserialize, FromField, Packable, Serialize, ToField},
+};
 use std::meta::derive;
 
 global NUMBER_OF_PLAYERS: u32 = 2;
 global NUMBER_OF_CARDS_DECK: u32 = 2;
 
-#[derive(Deserialize, Eq)]
+#[derive(Serialize, Deserialize, Eq)]
 pub struct PlayerEntry {
     pub address: AztecAddress,
     pub deck_strength: u32,
@@ -38,6 +41,7 @@ impl PlayerEntry {
 
 pub global PLAYABLE_CARDS: u32 = 4;
 
+#[derive(Serialize, Deserialize)]
 pub struct Game {
     players: [PlayerEntry; NUMBER_OF_PLAYERS],
     pub rounds_cards: [Card; PLAYABLE_CARDS],
diff --git a/noir-projects/noir-contracts/contracts/test/offchain_effect_contract/src/main.nr b/noir-projects/noir-contracts/contracts/test/offchain_effect_contract/src/main.nr
index f244eba56c97..2096f85a2340 100644
--- a/noir-projects/noir-contracts/contracts/test/offchain_effect_contract/src/main.nr
+++ b/noir-projects/noir-contracts/contracts/test/offchain_effect_contract/src/main.nr
@@ -13,7 +13,7 @@ contract OffchainEffect {
         },
         note::note_viewer_options::NoteViewerOptions,
         oracle::offchain_effect::emit_offchain_effect,
-        protocol::{address::AztecAddress, traits::Serialize},
+        protocol::{address::AztecAddress, traits::{Deserialize, Serialize}},
         state_vars::{Owned, PrivateSet},
     };
     use uint_note::UintNote;
@@ -25,7 +25,7 @@ contract OffchainEffect {
         pub c: u64,
     }
 
-    #[derive(Serialize)]
+    #[derive(Deserialize, Serialize)]
     pub struct EffectPayload {
         pub data: [Field; 5],
         pub next_contract: AztecAddress,
diff --git a/noir-projects/noir-contracts/contracts/test/unit_return_type_contract/Nargo.toml b/noir-projects/noir-contracts/contracts/test/unit_return_type_contract/Nargo.toml
new file mode 100644
index 000000000000..c6d3024c414c
--- /dev/null
+++ b/noir-projects/noir-contracts/contracts/test/unit_return_type_contract/Nargo.toml
@@ -0,0 +1,8 @@
+[package]
+name = "unit_return_type_contract"
+authors = [""]
+compiler_version = ">=0.25.0"
+type = "contract"
+
+[dependencies]
+aztec = { path = "../../../../aztec-nr/aztec" }
diff --git a/noir-projects/noir-contracts/contracts/test/unit_return_type_contract/src/main.nr b/noir-projects/noir-contracts/contracts/test/unit_return_type_contract/src/main.nr
new file mode 100644
index 000000000000..7ebeb4d06e00
--- /dev/null
+++ b/noir-projects/noir-contracts/contracts/test/unit_return_type_contract/src/main.nr
@@ -0,0 +1,16 @@
+// Verifies that contract functions with a unit return type `()` compile without requiring Serialize or Deserialize.
+use aztec::macros::aztec;
+
+#[aztec]
+pub contract UnitReturnType {
+    use aztec::macros::functions::external;
+
+    #[external("private")]
+    fn private_unit_return(_x: Field) {}
+
+    #[external("public")]
+    fn public_unit_return(_x: Field) {}
+
+    #[external("utility")]
+    unconstrained fn utility_unit_return(_x: Field) {}
+}