diff --git a/crates/tor-hsservice/src/ipt_mgr.rs b/crates/tor-hsservice/src/ipt_mgr.rs
index d956671dd..f856905cb 100644
--- a/crates/tor-hsservice/src/ipt_mgr.rs
+++ b/crates/tor-hsservice/src/ipt_mgr.rs
@@ -32,7 +32,7 @@ use tor_rtcompat::Runtime;
 use crate::svc::ipt_establish;
 use crate::timeout_track::{TrackingInstantOffsetNow, TrackingNow};
 use crate::{FatalError, OnionServiceConfig, RendRequest, StartupError};
-use ipt_establish::{IptEstablisher, IptStatus, IptStatusStatus, IptWantsToRetire};
+use ipt_establish::{IptEstablisher, IptParameters, IptStatus, IptStatusStatus, IptWantsToRetire};
 
 use IptStatusStatus as ISS;
 use TrackedStatus as TS;
@@ -305,12 +305,22 @@ impl IptRelay {
     /// Make a new introduction point at this relay
     ///
     /// It becomes the current IPT.
+    #[allow(unreachable_code, clippy::diverging_sub_expression)] // TODO HSS remove
     fn make_new_ipt<R: Runtime, M: Mockable<R>>(
         &mut self,
         imm: &Immutable<R>,
         mockable: &mut M,
     ) -> Result<(), FatalError> {
-        let (establisher, mut watch_rx) = mockable.make_new_ipt(imm, self.relay.clone())?;
+        let params = IptParameters {
+            netdir_provider: imm.dirprovider.clone(),
+            introduce_tx: imm.output_rend_reqs.clone(),
+            // TODO HSS IntroPointId lacks a constructor and maybe should change anyway
+            intro_pt_id: todo!(),
+            target: self.relay.clone(),
+            ipt_sid_keypair: todo!(), // TODO HSS
+            accepting_requests: todo!(), // TODO HSS
+        };
+        let (establisher, mut watch_rx) = mockable.make_new_ipt(imm, params)?;
 
         // we'll treat it as Establishing until we find otherwise
         let status_last = TS::Establishing {
@@ -735,7 +745,7 @@ pub(crate) trait Mockable<R>: Debug + Send + Sync + Sized + 'static {
     fn make_new_ipt(
         &mut self,
         imm: &Immutable<R>,
-        relay: RelayIds,
+        params: IptParameters,
     ) -> Result<(Self::IptEstablisher, watch::Receiver<IptStatus>), FatalError>;
 
     /// Call `Publisher::new_intro_points`
@@ -755,21 +765,15 @@ impl<R: Runtime> Mockable<R> for Real<R> {
         rand::thread_rng()
     }
 
-    #[allow(unreachable_code)] // TODO HSS remove
     fn make_new_ipt(
         &mut self,
         imm: &Immutable<R>,
-        relay: RelayIds,
+        params: IptParameters,
     ) -> Result<(Self::IptEstablisher, watch::Receiver<IptStatus>), FatalError> {
         IptEstablisher::new(
             imm.runtime.clone(),
+            params,
             self.circ_pool.clone(),
-            imm.dirprovider.clone(),
-            imm.output_rend_reqs.clone(),
-            todo!(), // TODO HSS IntroPointId lacks a constructor and maybe should change anyway
-            relay,
-            todo!(), // TODO HSS keypair ought to be provided by our caller
-            todo!(), // TODO HSS RequestDisposition ought to be provided by our caller
         )
     }
 }
diff --git a/crates/tor-hsservice/src/svc/ipt_establish.rs b/crates/tor-hsservice/src/svc/ipt_establish.rs
index 7157b1ebb..1e642c344 100644
--- a/crates/tor-hsservice/src/svc/ipt_establish.rs
+++ b/crates/tor-hsservice/src/svc/ipt_establish.rs
@@ -151,6 +151,27 @@ impl IptError {
     }
 }
 
+/// Parameters for an introduction point
+///
+/// Consumed by `IptEstablisher::new`.
+/// Primarily serves as a convenient way to bundle the many arguments required.
+///
+/// Does not include:
+///  * The runtime (which would force this struct to have a type parameter)
+///  * The circuit builder (leaving this out makes it possible to use this
+///    struct during mock execution, where we don't call `IptEstablisher::new`).
+#[allow(clippy::missing_docs_in_private_items)] // TODO HSS document these and remove
+pub(crate) struct IptParameters {
+    pub(crate) netdir_provider: Arc<dyn NetDirProvider>,
+    pub(crate) introduce_tx: mpsc::Sender<RendRequest>,
+    pub(crate) intro_pt_id: IntroPointId,
+    // TODO HSS: Should this and the following elements be part of some
+    // configuration object?
+    pub(crate) target: RelayIds,
+    pub(crate) ipt_sid_keypair: HsIntroPtSessionIdKeypair,
+    pub(crate) accepting_requests: RequestDisposition,
+}
+
 impl IptEstablisher {
     /// Try to set up, and maintain, an IPT at `target`.
     ///
@@ -165,19 +186,21 @@ impl IptEstablisher {
     /// The returned `watch::Receiver` will yield `Faulty` if the IPT
     /// establisher is shut down (or crashes).
     // TODO HSS rename to "launch" since it starts the task?
-    #[allow(clippy::too_many_arguments)] // TODO HSS refactor.
     pub(crate) fn new<R: Runtime>(
         runtime: R,
+        params: IptParameters,
         pool: Arc<HsCircPool<R>>,
-        netdir_provider: Arc<dyn NetDirProvider>,
-        introduce_tx: mpsc::Sender<RendRequest>,
-        intro_pt_id: IntroPointId,
-        // TODO HSS: Should this and the following elements be part of some
-        // configuration object?
-        target: RelayIds,
-        ipt_sid_keypair: HsIntroPtSessionIdKeypair,
-        accepting_requests: RequestDisposition,
     ) -> Result<(Self, postage::watch::Receiver<IptStatus>), FatalError> {
+        // This exhaustive deconstruction ensures that we don't
+        // accidentally forget to handle any of our inputs.
+        let IptParameters {
+            netdir_provider,
+            introduce_tx,
+            intro_pt_id,
+            target,
+            ipt_sid_keypair,
+            accepting_requests,
+        } = params;
         if matches!(accepting_requests, RequestDisposition::Shutdown) {
             return Err(bad_api_usage!(
                 "Tried to create a IptEstablisher that that was already shutting down?"