diff --git a/src/agent/channel.rs b/src/agent/channel.rs
index 4daddff19..6589e4420 100644
--- a/src/agent/channel.rs
+++ b/src/agent/channel.rs
@@ -516,12 +516,13 @@ impl Channel {
     }
 
     /// Get the agent's display name (falls back to agent ID).
-    fn agent_display_name(&self) -> &str {
+    fn agent_display_name(&self) -> String {
         self.deps
             .agent_names
+            .load()
             .get(self.deps.agent_id.as_ref())
-            .map(String::as_str)
-            .unwrap_or(self.deps.agent_id.as_ref())
+            .cloned()
+            .unwrap_or_else(|| self.deps.agent_id.to_string())
     }
 
     fn current_adapter(&self) -> Option<&str> {
@@ -793,10 +794,11 @@ impl Channel {
                         .with_label_values(&[&self.deps.agent_id, channel_type])
                         .inc();
                 }
+                let display_name = self.agent_display_name();
                 self.state.conversation_logger.log_bot_message_with_name(
                     &self.state.channel_id,
                     &text,
-                    Some(self.agent_display_name()),
+                    Some(&display_name),
                 );
             }
             Err(error) => {
@@ -1944,6 +1946,7 @@ impl Channel {
                 let name = self
                     .deps
                     .agent_names
+                    .load()
                     .get(other_id.as_str())
                     .cloned()
                     .unwrap_or_else(|| other_id.clone());
@@ -2541,10 +2544,11 @@ impl Channel {
                             if extracted.is_some() {
                                 tracing::warn!(channel_id = %self.id, "extracted reply from malformed tool syntax in LLM text output");
                             }
+                            let display_name = self.agent_display_name();
                             self.state.conversation_logger.log_bot_message_with_name(
                                 &self.state.channel_id,
                                 &final_text,
-                                Some(self.agent_display_name()),
+                                Some(&display_name),
                             );
                             self.send_outbound_text(final_text, "failed to send fallback reply")
                                 .await;
diff --git a/src/agent/cortex.rs b/src/agent/cortex.rs
index 8e350e6e1..328045729 100644
--- a/src/agent/cortex.rs
+++ b/src/agent/cortex.rs
@@ -2519,7 +2519,8 @@ async fn pickup_one_ready_task(deps: &AgentDeps, logger: &CortexLogger) -> anyho
     let logger = logger.clone();
     let injection_tx = deps.injection_tx.clone();
     let links = deps.links.clone();
-    let agent_names = deps.agent_names.clone();
+    let agent_names: Arc<std::collections::HashMap<String, String>> =
+        deps.agent_names.load_full();
     let sqlite_pool = deps.sqlite_pool.clone();
     let secrets_snapshot = deps.runtime_config.secrets.load().clone();
     let process_control_registry = deps.process_control_registry.clone();
diff --git a/src/api/agents.rs b/src/api/agents.rs
index ce75842c1..8d71b4823 100644
--- a/src/api/agents.rs
+++ b/src/api/agents.rs
@@ -413,6 +413,7 @@ pub(super) async fn trigger_warmup(
         let task_store_registry = state.task_store_registry.clone();
         let injection_tx = state.injection_tx.clone();
         let humans = (**state.agent_humans.load()).clone();
+        let agent_names = state.agent_names.clone();
         tokio::spawn(async move {
             let (event_tx, memory_event_tx) = crate::create_process_event_buses();
             let project_store =
@@ -432,7 +433,7 @@ pub(super) async fn trigger_warmup(
                 task_store,
                 project_store,
                 links: Arc::new(arc_swap::ArcSwap::from_pointee(Vec::new())),
-                agent_names: Arc::new(std::collections::HashMap::new()),
+                agent_names,
                 humans: Arc::new(arc_swap::ArcSwap::from_pointee(humans)),
                 task_store_registry,
                 process_control_registry: Arc::new(
@@ -764,6 +765,20 @@ pub async fn create_agent_internal(
     // Inject active project root paths into the sandbox allowlist.
     crate::projects::refresh_sandbox_project_paths(&project_store, &arc_agent_id, &sandbox).await;
 
+    // Update the shared agent name registry to include this new agent so all
+    // existing agents can resolve it immediately via their Arc<ArcSwap<...>>.
+    {
+        let new_agent_name = request
+            .display_name
+            .as_deref()
+            .filter(|s| !s.is_empty())
+            .unwrap_or(&agent_id)
+            .to_string();
+        let mut names = (**state.agent_names.load()).clone();
+        names.insert(agent_id.clone(), new_agent_name);
+        state.agent_names.store(std::sync::Arc::new(names));
+    }
+
     let deps = crate::AgentDeps {
         agent_id: arc_agent_id.clone(),
         memory_search: memory_search.clone(),
@@ -789,26 +804,7 @@ pub async fn create_agent_internal(
             crate::agent::process_control::ProcessControlRegistry::new(),
         ),
         injection_tx: state.injection_tx.clone(),
-        agent_names: {
-            let configs = state.agent_configs.load();
-            let mut names: std::collections::HashMap<String, String> = configs
-                .iter()
-                .map(|c| {
-                    (
-                        c.id.clone(),
-                        c.display_name.clone().unwrap_or_else(|| c.id.clone()),
-                    )
-                })
-                .collect();
-            names.entry(agent_id.clone()).or_insert_with(|| {
-                request
-                    .display_name
-                    .clone()
-                    .filter(|s| !s.is_empty())
-                    .unwrap_or_else(|| agent_id.clone())
-            });
-            Arc::new(names)
-        },
+        agent_names: state.agent_names.clone(),
         humans: Arc::new(arc_swap::ArcSwap::from_pointee(
             (**state.agent_humans.load()).clone(),
         )),
diff --git a/src/api/state.rs b/src/api/state.rs
index 9500617e1..30fb5826c 100644
--- a/src/api/state.rs
+++ b/src/api/state.rs
@@ -123,6 +123,8 @@ pub struct ApiState {
     /// Cross-agent task store registry for delegation.
     pub task_store_registry:
         Arc<ArcSwap<std::collections::HashMap<String, Arc<crate::tasks::TaskStore>>>>,
+    /// Shared agent name map for resolving agent IDs to display names (hot-reloadable).
+    pub agent_names: Arc<ArcSwap<std::collections::HashMap<String, String>>>,
     /// Sender for cross-agent message injection.
     pub injection_tx: mpsc::Sender<crate::ChannelInjection>,
     /// Instance-level agent links for the communication graph.
@@ -289,6 +291,7 @@ impl ApiState {
         task_store_registry: Arc<
             ArcSwap<std::collections::HashMap<String, Arc<crate::tasks::TaskStore>>>,
         >,
+        agent_names: Arc<ArcSwap<std::collections::HashMap<String, String>>>,
     ) -> Self {
         let (event_tx, _) = broadcast::channel(512);
         Self {
@@ -328,6 +331,7 @@ impl ApiState {
             agent_tx,
             agent_remove_tx,
             task_store_registry,
+            agent_names,
             injection_tx,
             webchat_adapter: ArcSwap::from_pointee(None),
             agent_links: ArcSwap::from_pointee(Vec::new()),
diff --git a/src/hooks/loop_guard.rs b/src/hooks/loop_guard.rs
index 0e28c4a31..bc61f8f4a 100644
--- a/src/hooks/loop_guard.rs
+++ b/src/hooks/loop_guard.rs
@@ -448,12 +448,8 @@ impl LoopGuard {
         hasher.update(b"|");
         hasher.update(args.as_bytes());
         hasher.update(b"|");
-        let truncated = if result.len() > RESULT_HASH_TRUNCATION {
-            &result[..RESULT_HASH_TRUNCATION]
-        } else {
-            result
-        };
-        hasher.update(truncated.as_bytes());
+        let result_bytes = result.as_bytes();
+        hasher.update(&result_bytes[..result_bytes.len().min(RESULT_HASH_TRUNCATION)]);
         hex::encode(hasher.finalize())
     }
 }
diff --git a/src/lib.rs b/src/lib.rs
index fba359745..8a79be1a8 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -393,7 +393,8 @@ pub struct AgentDeps {
     pub sandbox: Arc<sandbox::Sandbox>,
     pub links: Arc<arc_swap::ArcSwap<Vec<links::AgentLink>>>,
     /// Map of all agent IDs to display names, for inter-agent message routing.
-    pub agent_names: Arc<std::collections::HashMap<String, String>>,
+    /// Hot-reloadable: updated when agents are added or reconfigured.
+    pub agent_names: Arc<arc_swap::ArcSwap<std::collections::HashMap<String, String>>>,
     /// Org-level human definitions (hot-reloadable). Used by `build_org_context()`
     /// to surface human display names, roles, and descriptions in agent prompts.
     pub humans: Arc<arc_swap::ArcSwap<Vec<config::HumanDef>>>,
diff --git a/src/main.rs b/src/main.rs
index 713802d78..d11708b9b 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1444,6 +1444,10 @@ async fn run(
         ArcSwap<std::collections::HashMap<String, Arc<spacebot::tasks::TaskStore>>>,
     > = Arc::new(ArcSwap::from_pointee(std::collections::HashMap::new()));
 
+    let agent_names_registry: Arc<
+        ArcSwap<std::collections::HashMap<String, String>>,
+    > = Arc::new(ArcSwap::from_pointee(std::collections::HashMap::new()));
+
     // Start HTTP API server if enabled
     let mut api_state = spacebot::api::ApiState::new_with_provider_sender(
         provider_tx,
@@ -1451,6 +1455,7 @@ async fn run(
         agent_remove_tx,
         injection_tx.clone(),
         task_store_registry.clone(),
+        agent_names_registry.clone(),
     );
     api_state.auth_token = config.api.auth_token.clone();
     let api_state = Arc::new(api_state);
@@ -1608,6 +1613,7 @@ async fn run(
             agent_humans.clone(),
             injection_tx.clone(),
             task_store_registry.clone(),
+            agent_names_registry.clone(),
             &bootstrapped_store,
         )
         .await?;
@@ -2337,6 +2343,7 @@ async fn run(
                                     agent_humans.clone(),
                                     injection_tx.clone(),
                                     task_store_registry.clone(),
+                                    agent_names_registry.clone(),
                                     &bootstrapped_store,
                                 ).await {
                                     Ok(()) => {
@@ -2478,20 +2485,21 @@ async fn initialize_agents(
     task_store_registry: Arc<
         ArcSwap<std::collections::HashMap<String, Arc<spacebot::tasks::TaskStore>>>,
     >,
+    agent_names_registry: Arc<ArcSwap<std::collections::HashMap<String, String>>>,
     bootstrapped_store: &Option<Arc<spacebot::secrets::store::SecretsStore>>,
 ) -> anyhow::Result<()> {
     let resolved_agents = config.resolve_agents();
 
-    // Build agent name map for inter-agent message routing
-    let agent_name_map: Arc<std::collections::HashMap<String, String>> = Arc::new(
-        resolved_agents
-            .iter()
-            .map(|a| {
-                let name = a.display_name.clone().unwrap_or_else(|| a.id.clone());
-                (a.id.clone(), name)
-            })
-            .collect(),
-    );
+    // Build agent name map and publish to the shared registry so all agents
+    // (including those already running) see the updated names immediately.
+    let agent_name_map: std::collections::HashMap<String, String> = resolved_agents
+        .iter()
+        .map(|a| {
+            let name = a.display_name.clone().unwrap_or_else(|| a.id.clone());
+            (a.id.clone(), name)
+        })
+        .collect();
+    agent_names_registry.store(Arc::new(agent_name_map));
 
     for agent_config in &resolved_agents {
         tracing::info!(agent_id = %agent_config.id, "initializing agent");
@@ -2713,7 +2721,7 @@ async fn initialize_agents(
             messaging_manager: None,
             sandbox,
             links: agent_links.clone(),
-            agent_names: agent_name_map.clone(),
+            agent_names: agent_names_registry.clone(),
             humans: agent_humans.clone(),
             task_store_registry: task_store_registry.clone(),
             process_control_registry: Arc::new(
diff --git a/src/tools.rs b/src/tools.rs
index 4ed3bd7f5..0d79bf977 100644
--- a/src/tools.rs
+++ b/src/tools.rs
@@ -348,6 +348,7 @@ pub async fn add_channel_tools(
         let agent_display_name = state
             .deps
             .agent_names
+            .load()
             .get(state.deps.agent_id.as_ref())
             .cloned()
             .unwrap_or_else(|| state.deps.agent_id.to_string());
@@ -369,6 +370,7 @@ pub async fn add_channel_tools(
         let send_message_display_name = state
             .deps
             .agent_names
+            .load()
             .get(state.deps.agent_id.as_ref())
             .cloned()
             .unwrap_or_else(|| state.deps.agent_id.to_string());
diff --git a/src/tools/send_agent_message.rs b/src/tools/send_agent_message.rs
index 213f1da31..dec8343ad 100644
--- a/src/tools/send_agent_message.rs
+++ b/src/tools/send_agent_message.rs
@@ -30,7 +30,7 @@ pub struct SendAgentMessageTool {
     agent_id: crate::AgentId,
     links: Arc<ArcSwap<Vec<AgentLink>>>,
     /// Map of known agent IDs to display names, for resolving targets.
-    agent_names: Arc<HashMap<String, String>>,
+    agent_names: Arc<ArcSwap<HashMap<String, String>>>,
     /// Cross-agent task store registry for creating tasks on target agents.
     task_store_registry: Arc<ArcSwap<HashMap<String, Arc<TaskStore>>>>,
     /// Per-agent conversation logger for writing link channel audit records.
@@ -54,7 +54,7 @@ impl SendAgentMessageTool {
     pub fn new(
         agent_id: crate::AgentId,
         links: Arc<ArcSwap<Vec<AgentLink>>>,
-        agent_names: Arc<HashMap<String, String>>,
+        agent_names: Arc<ArcSwap<HashMap<String, String>>>,
         task_store_registry: Arc<ArcSwap<HashMap<String, Arc<TaskStore>>>>,
         conversation_logger: ConversationLogger,
     ) -> Self {
@@ -85,14 +85,16 @@ impl SendAgentMessageTool {
     /// Resolve an agent target string to an agent ID.
     /// Checks both IDs and display names (case-insensitive).
     fn resolve_agent_id(&self, target: &str) -> Option<String> {
+        let names = self.agent_names.load();
+
         // Direct ID match
-        if self.agent_names.contains_key(target) {
+        if names.contains_key(target) {
             return Some(target.to_string());
         }
 
         // Name match (case-insensitive)
         let target_lower = target.to_lowercase();
-        for (agent_id, name) in self.agent_names.iter() {
+        for (agent_id, name) in names.iter() {
             if name.to_lowercase() == target_lower {
                 return Some(agent_id.clone());
             }
@@ -199,6 +201,7 @@ impl Tool for SendAgentMessageTool {
 
         let target_display = self
             .agent_names
+            .load()
             .get(receiving_agent_id)
             .cloned()
             .unwrap_or_else(|| receiving_agent_id.to_string());
@@ -249,6 +252,7 @@ impl Tool for SendAgentMessageTool {
         // Log delegation record in the link channel (system message).
         let sender_display = self
             .agent_names
+            .load()
             .get(sending_agent_id)
             .cloned()
             .unwrap_or_else(|| sending_agent_id.to_string());