diff --git a/artifacts/program_methods/cross_zone_outbox.bin b/artifacts/program_methods/cross_zone_outbox.bin
index b89f8d0f..e87cd663 100644
Binary files a/artifacts/program_methods/cross_zone_outbox.bin and b/artifacts/program_methods/cross_zone_outbox.bin differ
diff --git a/artifacts/program_methods/ping_sender.bin b/artifacts/program_methods/ping_sender.bin
new file mode 100644
index 00000000..c2480bc3
Binary files /dev/null and b/artifacts/program_methods/ping_sender.bin differ
diff --git a/lee/state_machine/src/program.rs b/lee/state_machine/src/program.rs
index 8b71448b..e5ee73d6 100644
--- a/lee/state_machine/src/program.rs
+++ b/lee/state_machine/src/program.rs
@@ -13,7 +13,8 @@ use crate::{
         AUTHENTICATED_TRANSFER_ELF, AUTHENTICATED_TRANSFER_ID, BRIDGE_ELF, BRIDGE_ID, CLOCK_ELF,
         CLOCK_ID, CROSS_ZONE_INBOX_ELF, CROSS_ZONE_INBOX_ID, CROSS_ZONE_OUTBOX_ELF,
         CROSS_ZONE_OUTBOX_ID, FAUCET_ELF, FAUCET_ID, PINATA_ELF, PINATA_ID, PING_RECEIVER_ELF,
-        PING_RECEIVER_ID, TOKEN_ELF, TOKEN_ID, VAULT_ELF, VAULT_ID,
+        PING_RECEIVER_ID, PING_SENDER_ELF, PING_SENDER_ID, TOKEN_ELF, TOKEN_ID, VAULT_ELF,
+        VAULT_ID,
     },
 };
 
@@ -198,6 +199,14 @@ impl Program {
             elf: PING_RECEIVER_ELF.to_vec(),
         }
     }
+
+    #[must_use]
+    pub fn ping_sender() -> Self {
+        Self {
+            id: PING_SENDER_ID,
+            elf: PING_SENDER_ELF.to_vec(),
+        }
+    }
 }
 
 // TODO: Testnet only. Refactor to prevent compilation on mainnet.
diff --git a/program_methods/guest/src/bin/cross_zone_outbox.rs b/program_methods/guest/src/bin/cross_zone_outbox.rs
index 84805807..432e8d9c 100644
--- a/program_methods/guest/src/bin/cross_zone_outbox.rs
+++ b/program_methods/guest/src/bin/cross_zone_outbox.rs
@@ -20,13 +20,20 @@ fn main() {
         "Outbox is only callable through a chain call from a user program"
     );
 
-    let (target_zone, target_program_id, payload, ordinal) = match instruction {
+    let (target_zone, target_program_id, target_accounts, payload, ordinal) = match instruction {
         Instruction::Emit {
             target_zone,
             target_program_id,
+            target_accounts,
             payload,
             ordinal,
-        } => (target_zone, target_program_id, payload, ordinal),
+        } => (
+            target_zone,
+            target_program_id,
+            target_accounts,
+            payload,
+            ordinal,
+        ),
     };
 
     let [outbox] =
@@ -42,6 +49,7 @@ fn main() {
     post_account.data = OutboxRecord {
         target_zone,
         target_program_id,
+        target_accounts,
         payload,
     }
     .to_bytes()
diff --git a/program_methods/guest/src/bin/ping_sender.rs b/program_methods/guest/src/bin/ping_sender.rs
new file mode 100644
index 00000000..d0ad04f5
--- /dev/null
+++ b/program_methods/guest/src/bin/ping_sender.rs
@@ -0,0 +1,59 @@
+use cross_zone_outbox_core::Instruction as OutboxInstruction;
+use lee_core::{
+    account::AccountWithMetadata,
+    program::{AccountPostState, ChainedCall, ProgramInput, ProgramOutput, read_lee_inputs},
+};
+use ping_core::SenderInstruction;
+
+fn main() {
+    let (
+        ProgramInput {
+            self_program_id,
+            caller_program_id,
+            pre_states,
+            instruction,
+        },
+        instruction_words,
+    ) = read_lee_inputs::<SenderInstruction>();
+
+    assert!(
+        caller_program_id.is_none(),
+        "ping_sender is only invoked as a top-level user transaction"
+    );
+
+    let SenderInstruction::Send {
+        outbox_program_id,
+        target_zone,
+        target_program_id,
+        target_accounts,
+        payload,
+        ordinal,
+    } = instruction;
+
+    // The single account is the outbox PDA the chained call writes into; the
+    // outbox claims it, so ping_sender forwards it unchanged.
+    let [outbox] =
+        <[AccountWithMetadata; 1]>::try_from(pre_states).expect("Send requires exactly 1 account");
+
+    let call = ChainedCall::new(
+        outbox_program_id,
+        vec![outbox.clone()],
+        &OutboxInstruction::Emit {
+            target_zone,
+            target_program_id,
+            target_accounts,
+            payload,
+            ordinal,
+        },
+    );
+
+    ProgramOutput::new(
+        self_program_id,
+        caller_program_id,
+        instruction_words,
+        vec![outbox.clone()],
+        vec![AccountPostState::new(outbox.account)],
+    )
+    .with_chained_calls(vec![call])
+    .write();
+}
diff --git a/programs/cross_zone_outbox/core/src/lib.rs b/programs/cross_zone_outbox/core/src/lib.rs
index 528cf769..b3449598 100644
--- a/programs/cross_zone_outbox/core/src/lib.rs
+++ b/programs/cross_zone_outbox/core/src/lib.rs
@@ -19,6 +19,10 @@ pub enum Instruction {
     Emit {
         target_zone: ZoneId,
         target_program_id: ProgramId,
+        /// Accounts the destination inbox must hand to the target program's
+        /// chained call. The emitter specifies them; the watcher forwards them
+        /// verbatim so the inbox stays target-agnostic.
+        target_accounts: Vec<[u8; 32]>,
         payload: Vec<u8>,
         ordinal: u32,
     },
@@ -31,6 +35,7 @@ pub enum Instruction {
 pub struct OutboxRecord {
     pub target_zone: ZoneId,
     pub target_program_id: ProgramId,
+    pub target_accounts: Vec<[u8; 32]>,
     pub payload: Vec<u8>,
 }
 
diff --git a/programs/ping/core/src/lib.rs b/programs/ping/core/src/lib.rs
index f6b5b963..268e5b98 100644
--- a/programs/ping/core/src/lib.rs
+++ b/programs/ping/core/src/lib.rs
@@ -12,6 +12,19 @@ pub enum ReceiverInstruction {
     Record { payload: Vec<u8> },
 }
 
+/// Instruction to `ping_sender`: forwarded verbatim into `cross_zone_outbox::Instruction::Emit`.
+#[derive(Clone, Debug, PartialEq, Eq, Serialize, Deserialize)]
+pub enum SenderInstruction {
+    Send {
+        outbox_program_id: ProgramId,
+        target_zone: [u8; 32],
+        target_program_id: ProgramId,
+        target_accounts: Vec<[u8; 32]>,
+        payload: Vec<u8>,
+        ordinal: u32,
+    },
+}
+
 /// The account a `ping_receiver` records the latest delivered payload into.
 #[must_use]
 pub fn ping_record_pda(receiver_id: ProgramId) -> AccountId {