diff --git a/magic-nix-cache/src/main.rs b/magic-nix-cache/src/main.rs
index 8ff28f3..d8aaa6f 100644
--- a/magic-nix-cache/src/main.rs
+++ b/magic-nix-cache/src/main.rs
@@ -18,6 +18,7 @@ mod env;
 mod error;
 mod flakehub;
 mod gha;
+mod pbh;
 mod telemetry;
 mod util;
 
@@ -34,10 +35,10 @@ use anyhow::{anyhow, Context, Result};
 use axum::body::Body;
 use axum::{extract::Extension, routing::get, Router};
 use clap::Parser;
+use futures::StreamExt;
 use http_body_util::BodyExt;
 use hyper_util::rt::{TokioExecutor, TokioIo};
-use futures::StreamExt;
-use serde::{Deserialize,Serialize};
+use serde::{Deserialize, Serialize};
 use tempfile::NamedTempFile;
 use tokio::fs::File;
 use tokio::io::AsyncWriteExt;
@@ -53,7 +54,6 @@ use gha_cache::Credentials;
 const DETERMINATE_STATE_DIR: &str = "/nix/var/determinate";
 const DETERMINATE_NIXD_SOCKET_NAME: &str = "determinate-nixd.socket";
 
-
 // TODO(colemickens): refactor, move with other UDS stuff (or all PBH stuff) to new file
 #[derive(Clone, Debug, Serialize, Deserialize)]
 #[serde(tag = "c", rename_all = "kebab-case")]
@@ -338,7 +338,7 @@ async fn main_cli() -> Result<()> {
 
     if dnixd_uds_socket_path.exists() {
         let stream = TokioIo::new(UnixStream::connect(dnixd_uds_socket_path).await?);
-       
+
         // TODO(colemickens): loop retry/reconnect/etc
 
         let executor = TokioExecutor::new();
@@ -370,14 +370,20 @@ async fn main_cli() -> Result<()> {
                 None => {
                     tracing::debug!("built-paths subscription: ignoring non-data frame");
                     continue;
-                },
+                }
             };
             let event: BuiltPathResponseEventV1 = serde_json::from_slice(&event_str)?;
 
             // TODO(colemickens): error handling:::
-            let store_paths = event.outputs
+            let store_paths = event
+                .outputs
                 .iter()
-                .map(|path| state.store.follow_store_path(path).map_err(|_| anyhow!("ahhhhh")))
+                .map(|path| {
+                    state
+                        .store
+                        .follow_store_path(path)
+                        .map_err(|_| anyhow!("ahhhhh"))
+                })
                 .collect::<Result<Vec<_>>>()?;
 
             tracing::debug!("about to enqueue paths: {:?}", store_paths);
@@ -520,58 +526,10 @@ async fn main_cli() -> Result<()> {
     Ok(())
 }
 
-async fn post_build_hook(out_paths: &str) -> Result<()> {
-    #[derive(Parser, Debug)]
-    struct Args {
-        /// `magic-nix-cache` daemon to connect to.
-        #[arg(short = 'l', long, default_value = "127.0.0.1:3000")]
-        server: SocketAddr,
-    }
-
-    let args = Args::parse();
-
-    let store_paths: Vec<_> = out_paths
-        .split_whitespace()
-        .map(|s| s.trim().to_owned())
-        .collect();
-
-    let request = api::EnqueuePathsRequest { store_paths };
-
-    let response = reqwest::Client::new()
-        .post(format!("http://{}/api/enqueue-paths", &args.server))
-        .header(reqwest::header::CONTENT_TYPE, "application/json")
-        .body(
-            serde_json::to_string(&request)
-                .with_context(|| "Decoding the response from the magic-nix-cache server")?,
-        )
-        .send()
-        .await;
-
-    match response {
-        Ok(response) if !response.status().is_success() => Err(anyhow!(
-            "magic-nix-cache server failed to enqueue the push request: {}\n{}",
-            response.status(),
-            response
-                .text()
-                .await
-                .unwrap_or_else(|_| "<no response text>".to_owned()),
-        ))?,
-        Ok(response) => response
-            .json::<api::EnqueuePathsResponse>()
-            .await
-            .with_context(|| "magic-nix-cache-server didn't return a valid response")?,
-        Err(err) => {
-            Err(err).with_context(|| "magic-nix-cache server failed to send the enqueue request")?
-        }
-    };
-
-    Ok(())
-}
-
 #[tokio::main]
 async fn main() -> Result<()> {
     match std::env::var("OUT_PATHS") {
-        Ok(out_paths) => post_build_hook(&out_paths).await,
+        Ok(out_paths) => pbh::post_build_hook(&out_paths).await,
         Err(_) => main_cli().await,
     }
 }
diff --git a/magic-nix-cache/src/pbh.rs b/magic-nix-cache/src/pbh.rs
new file mode 100644
index 0000000..a0becb8
--- /dev/null
+++ b/magic-nix-cache/src/pbh.rs
@@ -0,0 +1,54 @@
+use std::net::SocketAddr;
+
+use anyhow::anyhow;
+use anyhow::Context as _;
+use anyhow::Result;
+use clap::Parser;
+
+pub async fn post_build_hook(out_paths: &str) -> Result<()> {
+    #[derive(Parser, Debug)]
+    struct Args {
+        /// `magic-nix-cache` daemon to connect to.
+        #[arg(short = 'l', long, default_value = "127.0.0.1:3000")]
+        server: SocketAddr,
+    }
+
+    let args = Args::parse();
+
+    let store_paths: Vec<_> = out_paths
+        .split_whitespace()
+        .map(|s| s.trim().to_owned())
+        .collect();
+
+    let request = crate::api::EnqueuePathsRequest { store_paths };
+
+    let response = reqwest::Client::new()
+        .post(format!("http://{}/api/enqueue-paths", &args.server))
+        .header(reqwest::header::CONTENT_TYPE, "application/json")
+        .body(
+            serde_json::to_string(&request)
+                .with_context(|| "Decoding the response from the magic-nix-cache server")?,
+        )
+        .send()
+        .await;
+
+    match response {
+        Ok(response) if !response.status().is_success() => Err(anyhow!(
+            "magic-nix-cache server failed to enqueue the push request: {}\n{}",
+            response.status(),
+            response
+                .text()
+                .await
+                .unwrap_or_else(|_| "<no response text>".to_owned()),
+        ))?,
+        Ok(response) => response
+            .json::<crate::api::EnqueuePathsResponse>()
+            .await
+            .with_context(|| "magic-nix-cache-server didn't return a valid response")?,
+        Err(err) => {
+            Err(err).with_context(|| "magic-nix-cache server failed to send the enqueue request")?
+        }
+    };
+
+    Ok(())
+}