diff --git a/Cargo.lock b/Cargo.lock
index 932defa4c..4b5c64ffe 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -3314,6 +3314,7 @@ dependencies = [
  "thiserror",
  "tor-circmgr",
  "tor-error",
+ "tor-linkspec",
  "tor-llcrypto",
  "tor-netdoc",
  "tor-proto",
diff --git a/crates/tor-dirclient/Cargo.toml b/crates/tor-dirclient/Cargo.toml
index 041e63ca5..2a3b730bc 100644
--- a/crates/tor-dirclient/Cargo.toml
+++ b/crates/tor-dirclient/Cargo.toml
@@ -20,6 +20,7 @@ routerdesc = []
 [dependencies]
 tor-circmgr = { path = "../tor-circmgr", version = "0.1.0" }
 tor-error = { path = "../tor-error", version = "0.1.0" }
+tor-linkspec = { path = "../tor-linkspec", version = "0.1.0" }
 tor-llcrypto = { path = "../tor-llcrypto", version = "0.1.0" }
 tor-proto = { path = "../tor-proto", version = "0.1.0" }
 tor-netdoc = { path = "../tor-netdoc", version = "0.1.0" }
diff --git a/crates/tor-dirclient/src/lib.rs b/crates/tor-dirclient/src/lib.rs
index 4dfa75fbe..d9f2e3490 100644
--- a/crates/tor-dirclient/src/lib.rs
+++ b/crates/tor-dirclient/src/lib.rs
@@ -111,7 +111,7 @@ where
 
     // TODO(nickm) This should be an option, and is too long.
     let begin_timeout = Duration::from_secs(5);
-    let source = SourceInfo::new(circuit.unique_id());
+    let source = SourceInfo::from_circuit(&circuit);
 
     // Launch the stream.
     let mut stream = runtime
diff --git a/crates/tor-dirclient/src/response.rs b/crates/tor-dirclient/src/response.rs
index 0d27ca9ed..dff122164 100644
--- a/crates/tor-dirclient/src/response.rs
+++ b/crates/tor-dirclient/src/response.rs
@@ -1,6 +1,7 @@
 //! Define a response type for directory requests.
 
-use tor_proto::circuit::UniqId;
+use tor_linkspec::OwnedChanTarget;
+use tor_proto::circuit::{ClientCirc, UniqId};
 
 use crate::Error;
 
@@ -22,13 +23,12 @@ pub struct DirResponse {
 ///
 /// We use this to remember when a request has failed, so we can
 /// abandon the circuit.
-///
-/// (In the future, we will probably want to use this structure to
-/// remember that the cache isn't working.)
 #[derive(Debug, Clone)]
 pub struct SourceInfo {
     /// Unique identifier for the circuit we're using
     circuit: UniqId,
+    /// Identity of the directory cache that provided us this information.
+    cache_id: OwnedChanTarget,
 }
 
 impl DirResponse {
@@ -85,12 +85,21 @@ impl DirResponse {
 
 impl SourceInfo {
     /// Construct a new SourceInfo
-    pub(crate) fn new(circuit: UniqId) -> Self {
-        SourceInfo { circuit }
+    pub(crate) fn from_circuit(circuit: &ClientCirc) -> Self {
+        SourceInfo {
+            circuit: circuit.unique_id(),
+            cache_id: circuit.first_hop(),
+        }
     }
+
     /// Return the unique circuit identifier for the circuit on which
     /// we received this info.
     pub fn unique_circ_id(&self) -> &UniqId {
         &self.circuit
     }
+
+    /// Return information about the peer from which we received this info.
+    pub fn cache_id(&self) -> &OwnedChanTarget {
+        &self.cache_id
+    }
 }