Feat/hyperbridge onboarding

frame/ismp-messaging/src/outbound.rs

@@ -62,8 +62,15 @@ pub fn post<T: Config>(
 	let commitment = pallet_ismp::Pallet::<T>::default()
 		.dispatch_request(
 			DispatchRequest::Post(post),
-			// Zero fee: relayer fees are disabled runtime-wide. A non-zero value would
-			// escrow funds that only a timeout releases.
+			// Zero fee, deliberately: Orbinum self-relays, and Hyperbridge's docs call
+			// that the intended integration — the relayer is paid offchain in BRIDGE
+			// rather than per-message on-chain. `dispatch_request` skips the transfer
+			// entirely when the fee is zero, so nothing is escrowed and nobody is owed.
+			//
+			// A non-zero fee is what Hyperbridge's permissionless relayer network reads
+			// to decide whether a message is worth delivering. Setting one only makes
+			// sense alongside dropping self-relay, and `Currency` would have to stop
+			// being the native token first — an external relayer cannot sell it.
 			FeeMetadata {
 				payer: payer::<T>(),
 				fee: Default::default(),

scripts/hyperbridge/relayer.paseo.toml

@@ -49,6 +49,12 @@ type = "grandpa"
 # Hyperbridge is a parachain: its GRANDPA finality comes from the RELAY chain
 # (Paseo), not from Hyperbridge itself.
 rpc = "wss://pas-rpc.stakeworld.io"   # dwellir stopped resolving (2026-08-27)
+# Required, not optional: `HostConfig` (tesseract/consensus/grandpa/src/lib.rs:85)
+# has no default, so omitting it fails with "missing field `slot_duration`" before
+# the relayer connects to anything. 6000 on Paseo; Polkadot mainnet would be 12000.
+slot_duration = 6000
+# How often to exchange consensus proofs, per the upstream docs.
+consensus_update_frequency = 60
 # Hyperbridge's para id on Paseo. Listing it is what makes the relayer ship
 # proofs that verify Hyperbridge *through* its relay's GRANDPA.
 para_ids = [4009]
@@ -68,6 +74,10 @@ consensus_state_id = "ORBI"
 type = "grandpa"
 # Orbinum is standalone, so this points at Orbinum itself.
 rpc = "wss://rpc-1.testnet.orbinum.io"
+# Orbinum's own block time, and the value the runtime whitelists Hyperbridge with
+# (`HYPERBRIDGE_SLOT_DURATION_MS`). Required, same as above.
+slot_duration = 6000
+consensus_update_frequency = 60
 # Empty: we are not a relay chain with parachains to prove.
 para_ids = []
 

template/runtime/src/configs/ismp/mod.rs

@@ -103,8 +103,13 @@ impl pallet_ismp::Config for Runtime {
 
 	type OffchainDB = ();
 
-	/// `POLICY = false` disables relayer fee charging: `on_executed` returns `Pays::No`
-	/// before touching balances. Switching it on is a mainnet-economics decision.
+	/// `POLICY = false` makes message *delivery* free for the submitter: `on_executed`
+	/// returns `Pays::No` before charging anyone (`fee_handler.rs:172`).
+	///
+	/// This is the inbound side, and it is separate from the relayer fee an outbound
+	/// message carries — that one lives in `FeeMetadata` and is zero because Orbinum
+	/// self-relays. Turning `POLICY` on would bill whoever submits an inbound message
+	/// for its execution weight, which is a mainnet-economics decision.
 	type FeeHandler = pallet_ismp::fee_handler::WeightFeeHandler<
 		AccountId,
 		Balances,