diff --git a/src/dag.rs b/src/dag.rs
index 753a206..5a2b74c 100644
--- a/src/dag.rs
+++ b/src/dag.rs
@@ -94,14 +94,14 @@ pub async fn build_flow_dag(
         .await
         .map_err(DagError::from)?;
     let caller_id = flow.caller_id();
-    let flow_job_ids = flow.jobs().clone();
+    let flow_job_ids = flow.jobs();
 
     // Build a set for faster membership tests
     let job_id_set: HashSet<u32> = flow_job_ids.iter().copied().collect();
 
     // Load all jobs
     let mut jobs: HashMap<u32, Job> = HashMap::with_capacity(flow_job_ids.len());
-    for jid in &flow_job_ids {
+    for jid in flow_job_ids {
         let job = redis
             .load_job(context_id, caller_id, *jid)
             .await
@@ -116,7 +116,7 @@ pub async fn build_flow_dag(
     let mut rev_adj: HashMap<u32, Vec<u32>> = HashMap::with_capacity(jobs.len());
     let mut in_degree: HashMap<u32, usize> = HashMap::with_capacity(jobs.len());
 
-    for &jid in &flow_job_ids {
+    for &jid in flow_job_ids {
         adj.entry(jid).or_default();
         rev_adj.entry(jid).or_default();
         in_degree.entry(jid).or_insert(0);
diff --git a/src/models/flow.rs b/src/models/flow.rs
index d726cbc..36b6922 100644
--- a/src/models/flow.rs
+++ b/src/models/flow.rs
@@ -42,7 +42,7 @@ impl Flow {
     pub fn context_id(&self) -> u32 {
         self.context_id
     }
-    pub fn jobs(&self) -> &Vec<u32> {
+    pub fn jobs(&self) -> &[u32] {
         &self.jobs
     }
 }
diff --git a/src/models/job.rs b/src/models/job.rs
index b3a7e79..18f7855 100644
--- a/src/models/job.rs
+++ b/src/models/job.rs
@@ -47,10 +47,10 @@ impl Job {
     pub fn context_id(&self) -> u32 {
         self.context_id
     }
-    pub fn depends(&self) -> &Vec<u32> {
+    pub fn depends(&self) -> &[u32] {
         &self.depends
     }
-    pub fn prerequisites(&self) -> &Vec<String> {
+    pub fn prerequisites(&self) -> &[String] {
         &self.prerequisites
     }
     pub fn script_type(&self) -> ScriptType {
diff --git a/src/service.rs b/src/service.rs
index 5c5d609..c8cee0c 100644
--- a/src/service.rs
+++ b/src/service.rs
@@ -1,4 +1,4 @@
-use crate::dag::{build_flow_dag, DagResult, FlowDag};
+use crate::dag::{DagResult, FlowDag, build_flow_dag};
 use crate::models::{Actor, Context, Flow, Job, JobStatus, Message, Runner};
 use crate::storage::RedisDriver;
 
@@ -95,17 +95,24 @@ impl AppService {
         Ok(job)
     }
 
-    pub async fn load_job(&self, context_id: u32, caller_id: u32, id: u32) -> Result<Job, BoxError> {
+    pub async fn load_job(
+        &self,
+        context_id: u32,
+        caller_id: u32,
+        id: u32,
+    ) -> Result<Job, BoxError> {
         let job = self.redis.load_job(context_id, caller_id, id).await?;
         Ok(job)
     }
 
     /// Update a job status with transition validation.
+    ///
     /// Allowed transitions:
     /// - Dispatched -> WaitingForPrerequisites | Started | Error
     /// - WaitingForPrerequisites -> Started | Error
     /// - Started -> Finished | Error
     /// - Finished, Error -> terminal (no transitions)
+    ///
     /// If the new status equals the current status, this is a no-op.
     pub async fn update_job_status(
         &self,
@@ -127,14 +134,10 @@ impl AppService {
                 new_status,
                 JobStatus::WaitingForPrerequisites | JobStatus::Started | JobStatus::Error
             ),
-            JobStatus::WaitingForPrerequisites => matches!(
-                new_status,
-                JobStatus::Started | JobStatus::Error
-            ),
-            JobStatus::Started => matches!(
-                new_status,
-                JobStatus::Finished | JobStatus::Error
-            ),
+            JobStatus::WaitingForPrerequisites => {
+                matches!(new_status, JobStatus::Started | JobStatus::Error)
+            }
+            JobStatus::Started => matches!(new_status, JobStatus::Finished | JobStatus::Error),
             JobStatus::Finished | JobStatus::Error => false,
         };
 
@@ -153,13 +156,23 @@ impl AppService {
     // -----------------------------
     // Message
     // -----------------------------
-    pub async fn create_message(&self, context_id: u32, message: Message) -> Result<Message, BoxError> {
+    pub async fn create_message(
+        &self,
+        context_id: u32,
+        message: Message,
+    ) -> Result<Message, BoxError> {
         self.redis.save_message(context_id, &message).await?;
         Ok(message)
     }
 
-    pub async fn load_message(&self, context_id: u32, caller_id: u32, id: u32) -> Result<Message, BoxError> {
+    pub async fn load_message(
+        &self,
+        context_id: u32,
+        caller_id: u32,
+        id: u32,
+    ) -> Result<Message, BoxError> {
         let msg = self.redis.load_message(context_id, caller_id, id).await?;
         Ok(msg)
     }
-}
\ No newline at end of file
+}
+