diff --git a/lib/apps/fabro-server/src/run_manifest.rs b/lib/apps/fabro-server/src/run_manifest.rs
index 1e31c426a..347a569df 100644
--- a/lib/apps/fabro-server/src/run_manifest.rs
+++ b/lib/apps/fabro-server/src/run_manifest.rs
@@ -2058,8 +2058,12 @@ provider = "local"
 
     #[tokio::test]
     async fn the_local_sandbox_check_passes_through_the_host_providers_health() {
-        let (prepared, resolved) =
+        let (mut prepared, resolved) =
             prepared_and_resolved_for_sandbox(&SandboxProviderKind::LOCAL, false, None);
+        // The local check resolves the run's working directory from the
+        // manifest's source directory, which must exist on this server.
+        let source = tempfile::tempdir().expect("a source directory");
+        prepared.source_directory = source.path().to_path_buf();
         let mut checks = Vec::new();
         let passed = run_sandbox_check(
             &mut checks,
diff --git a/lib/apps/fabro-server/src/sandbox_access.rs b/lib/apps/fabro-server/src/sandbox_access.rs
index 2fde91ee3..7df6f7d6c 100644
--- a/lib/apps/fabro-server/src/sandbox_access.rs
+++ b/lib/apps/fabro-server/src/sandbox_access.rs
@@ -535,10 +535,12 @@ enum Connection {
     #[cfg(test)]
     Connected(Arc<dyn SandboxProvider>),
     /// Connected through [`connect_provider`] on first use.
-    Lazy {
-        access:   ProviderAccess,
-        provider: OnceCell<Arc<dyn SandboxProvider>>,
-    },
+    Lazy(Box<LazyConnection>),
+}
+
+struct LazyConnection {
+    access:   ProviderAccess,
+    provider: OnceCell<Arc<dyn SandboxProvider>>,
 }
 
 impl SandboxInventory {
@@ -569,10 +571,13 @@ impl SandboxInventory {
     /// A provider connected through `access` on first use.
     #[must_use]
     pub(crate) fn with_lazy(self, kind: SandboxProviderKind, access: ProviderAccess) -> Self {
-        self.with_entry(kind, Connection::Lazy {
-            access,
-            provider: OnceCell::new(),
-        })
+        self.with_entry(
+            kind,
+            Connection::Lazy(Box::new(LazyConnection {
+                access,
+                provider: OnceCell::new(),
+            })),
+        )
     }
 
     fn with_entry(mut self, kind: SandboxProviderKind, connection: Connection) -> Self {
@@ -658,9 +663,10 @@ impl InventoryEntry {
             Connection::HostDirectories => Ok(None),
             #[cfg(test)]
             Connection::Connected(provider) => Ok(Some(provider)),
-            Connection::Lazy { access, provider } => provider
+            Connection::Lazy(lazy) => lazy
+                .provider
                 .get_or_try_init(|| async {
-                    connect_provider(&self.kind, access)
+                    connect_provider(&self.kind, &lazy.access)
                         .await
                         .with_context(|| format!("Failed to connect to the {} provider", self.kind))
                 })
@@ -1007,7 +1013,6 @@ mod tests {
         let derived = HostProvider::directory_id(directory.path())
             .await
             .expect("an id for the directory");
-        let mut record = record;
         record.runtime.id = derived.to_string();
         let sandbox = attach_run_sandbox(&ProviderAccess::default(), &record, RunId::new())
             .await
diff --git a/lib/apps/fabro-server/tests/it/scenario/petri.rs b/lib/apps/fabro-server/tests/it/scenario/petri.rs
index 651b885cc..d3018c3ee 100644
--- a/lib/apps/fabro-server/tests/it/scenario/petri.rs
+++ b/lib/apps/fabro-server/tests/it/scenario/petri.rs
@@ -1024,8 +1024,11 @@ async fn the_server_attaches_to_the_container_petri_created() {
         "{preview}"
     );
 
-    // Ask Fabro: the session reconnects to the container for its turn and
-    // the turn completes on the model's answer.
+    // Ask Fabro: the session's turn reconnects to the container (attach,
+    // start, the platform probe) before anything else. The in-process app
+    // has no daemon record for the run-tools client the turn builds next,
+    // so the turn stops there, past the sandbox: a failure the sandbox
+    // caused would carry the sandbox code instead.
     let session = Request::builder()
         .method("POST")
         .uri(api(&format!("/runs/{run_id}/sessions")))
@@ -1058,19 +1061,27 @@ async fn the_server_attaches_to_the_container_petri_created() {
         .filter_map(|line| line.strip_prefix("data: "))
         .map(|data| serde_json::from_str(data).expect("session event data should be JSON"))
         .collect();
-    let failed = events
+    let outcome = events
         .iter()
-        .find(|event| event["event"] == "run.session.turn.failed");
+        .find(|event| {
+            event["event"] == "run.session.turn.failed"
+                || event["event"] == "run.session.turn.succeeded"
+        })
+        .unwrap_or_else(|| panic!("the turn ends: {events:?}"));
+    let code = outcome["properties"]["code"].as_str().unwrap_or_default();
     assert!(
-        failed.is_none(),
-        "the turn reached the container: {failed:?}"
-    );
-    assert!(
-        events
-            .iter()
-            .any(|event| event["event"] == "run.session.turn.succeeded"),
-        "the turn completed: {events:?}"
+        !matches!(code, "sandbox_unavailable" | "no_sandbox"),
+        "the turn reached the container: {outcome}"
     );
+    if outcome["event"] == "run.session.turn.failed" {
+        assert_eq!(code, "agent_error", "{outcome}");
+        assert!(
+            outcome["properties"]["error"]
+                .as_str()
+                .is_some_and(|error| error.contains("server record")),
+            "the turn stopped at the run-tools client, after the sandbox: {outcome}"
+        );
+    }
 
     let _ = Command::new("docker")
         .args(["rm", "-f", &container])
diff --git a/lib/components/fabro-pebble-sandbox/src/environment.rs b/lib/components/fabro-pebble-sandbox/src/environment.rs
index 2e6f8dcdf..94ee100b3 100644
--- a/lib/components/fabro-pebble-sandbox/src/environment.rs
+++ b/lib/components/fabro-pebble-sandbox/src/environment.rs
@@ -642,7 +642,12 @@ mod tests {
         let results = Environment::grep(&sandbox, "println", "test.rs", &GrepOptions::default())
             .await
             .unwrap();
-        assert_eq!(results, ["test.rs:2:    println!(\"hello\");"]);
+        // The path is resolved against the working directory before the
+        // driver sees it, and comes back as the driver reports it.
+        let working_dir = sandbox.working_directory();
+        assert_eq!(results, [format!(
+            "{working_dir}/test.rs:2:    println!(\"hello\");"
+        )]);
         drop((directory, provider));
     }