diff --git a/crates/worker/src/ipc/interceptor.rs b/crates/worker/src/ipc/interceptor.rs
index 4f388853..55266d31 100644
--- a/crates/worker/src/ipc/interceptor.rs
+++ b/crates/worker/src/ipc/interceptor.rs
@@ -11,6 +11,7 @@ use std::borrow::Cow;
 use std::sync::atomic::{AtomicUsize, Ordering};
 use std::sync::{Arc, Mutex};
 
+use arc_swap::ArcSwap;
 use async_trait::async_trait;
 use llm_engine::Item;
 use llm_engine::UsageRecord;
@@ -64,7 +65,7 @@ pub(crate) struct WorkerInterceptor {
     pending_attachments: Arc<Mutex<Vec<SystemItem>>>,
     /// Prompt catalog used to render pending notification entries into the
     /// same system-message text that will be persisted in history.
-    prompts: Arc<PromptCatalog>,
+    prompts: Arc<ArcSwap<PromptCatalog>>,
     /// Type-erased commit handle. The interceptor uses it to commit
     /// `LogEntry::SystemItem` entries directly (sync) before
     /// returning the corresponding `Item::system_message`s up to the
@@ -84,7 +85,7 @@ impl WorkerInterceptor {
         usage_history: Option<Arc<Mutex<Vec<UsageRecord>>>>,
         pending_notifies: NotifyBuffer,
         pending_attachments: Arc<Mutex<Vec<SystemItem>>>,
-        prompts: Arc<PromptCatalog>,
+        prompts: Arc<ArcSwap<PromptCatalog>>,
         log_writer: Option<Arc<dyn SystemItemCommitter>>,
     ) -> Self {
         Self {
@@ -208,10 +209,11 @@ impl Interceptor for WorkerInterceptor {
             return Ok(Vec::new());
         }
 
+        let prompts = self.prompts.load_full();
         let mut system_items: Vec<SystemItem> = Vec::with_capacity(drained.len());
         let mut items: Vec<Item> = Vec::with_capacity(drained.len());
         for entry in drained {
-            match build_system_item(&entry, &self.prompts) {
+            match build_system_item(&entry, &prompts) {
                 Ok(system_item) => {
                     items.push(system_item.to_history_item());
                     system_items.push(system_item);
@@ -440,6 +442,10 @@ mod tests {
         HookTurnEndAction, OnTurnEnd, PostToolCall, PreLlmRequest, PreToolCall,
     };
 
+    fn test_prompts() -> Arc<ArcSwap<PromptCatalog>> {
+        Arc::new(ArcSwap::from(PromptCatalog::builtins_only().unwrap()))
+    }
+
     struct CountingHook(Arc<AtomicUsize>);
 
     #[async_trait]
@@ -541,7 +547,7 @@ mod tests {
             Some(history),
             NotifyBuffer::new(),
             Arc::new(Mutex::new(Vec::new())),
-            PromptCatalog::builtins_only().unwrap(),
+            test_prompts(),
             None,
         );
         let mut ctx = ctx_items;
@@ -571,7 +577,7 @@ mod tests {
             Some(history),
             NotifyBuffer::new(),
             Arc::new(Mutex::new(Vec::new())),
-            PromptCatalog::builtins_only().unwrap(),
+            test_prompts(),
             Some(Arc::new(RecordingSystemItemCommitter {
                 committed: Arc::clone(&committed),
             })),
@@ -609,7 +615,7 @@ mod tests {
             Some(history),
             NotifyBuffer::new(),
             Arc::new(Mutex::new(Vec::new())),
-            PromptCatalog::builtins_only().unwrap(),
+            test_prompts(),
             None,
         )
         .with_usage_tracker(usage_tracker);
@@ -634,7 +640,7 @@ mod tests {
             Some(history),
             NotifyBuffer::new(),
             Arc::new(Mutex::new(Vec::new())),
-            PromptCatalog::builtins_only().unwrap(),
+            test_prompts(),
             None,
         );
         let mut ctx = ctx_items;
@@ -675,7 +681,7 @@ mod tests {
             Some(history),
             NotifyBuffer::new(),
             Arc::new(Mutex::new(Vec::new())),
-            PromptCatalog::builtins_only().unwrap(),
+            test_prompts(),
             None,
         );
         let mut ctx = ctx_items;
@@ -702,7 +708,7 @@ mod tests {
             Some(history),
             NotifyBuffer::new(),
             Arc::new(Mutex::new(Vec::new())),
-            PromptCatalog::builtins_only().unwrap(),
+            test_prompts(),
             None,
         );
         let mut ctx = ctx_items;
@@ -723,7 +729,7 @@ mod tests {
             None,
             NotifyBuffer::new(),
             Arc::new(Mutex::new(Vec::new())),
-            PromptCatalog::builtins_only().unwrap(),
+            test_prompts(),
             None,
         );
         let mut ctx: Vec<Item> = Vec::new();
@@ -751,7 +757,7 @@ mod tests {
             None,
             NotifyBuffer::new(),
             Arc::new(Mutex::new(Vec::new())),
-            PromptCatalog::builtins_only().unwrap(),
+            test_prompts(),
             Some(committer),
         );
 
@@ -798,7 +804,7 @@ mod tests {
             None,
             NotifyBuffer::new(),
             Arc::new(Mutex::new(Vec::new())),
-            PromptCatalog::builtins_only().unwrap(),
+            test_prompts(),
             None,
         );
 
@@ -855,7 +861,7 @@ mod tests {
             None,
             NotifyBuffer::new(),
             Arc::new(Mutex::new(Vec::new())),
-            PromptCatalog::builtins_only().unwrap(),
+            test_prompts(),
             None,
         );
         let mut info = task_tool_call_info("TaskList", serde_json::json!({"scope": "all"}));
@@ -902,7 +908,7 @@ mod tests {
             None,
             NotifyBuffer::new(),
             Arc::new(Mutex::new(Vec::new())),
-            PromptCatalog::builtins_only().unwrap(),
+            test_prompts(),
             None,
         );
         let info = task_tool_call_info("TaskList", serde_json::json!({}));
@@ -953,7 +959,7 @@ mod tests {
             None,
             NotifyBuffer::new(),
             Arc::new(Mutex::new(Vec::new())),
-            PromptCatalog::builtins_only().unwrap(),
+            test_prompts(),
             None,
         );
         let history = vec![Item::user_message("hi"), Item::assistant_message("done")];
@@ -985,7 +991,7 @@ mod tests {
             None,
             NotifyBuffer::new(),
             Arc::new(Mutex::new(Vec::new())),
-            PromptCatalog::builtins_only().unwrap(),
+            test_prompts(),
             Some(Arc::new(RecordingSystemItemCommitter {
                 committed: Arc::clone(&committed),
             })),
@@ -1033,6 +1039,45 @@ mod tests {
         assert!(body.contains("track active work"));
     }
 
+    #[tokio::test]
+    async fn pending_notifications_use_the_latest_prompt_projection() {
+        let prompts = test_prompts();
+        let buffer = NotifyBuffer::new();
+        let interceptor = WorkerInterceptor::new(
+            Arc::new(HookRegistryBuilder::new().build()),
+            None,
+            None,
+            buffer.clone(),
+            Arc::new(Mutex::new(Vec::new())),
+            prompts.clone(),
+            None,
+        );
+
+        let current = prompts.load_full();
+        let projection = current.projection();
+        let mut templates = projection.templates.clone();
+        templates.insert(
+            "internal.notify_wrapper".to_string(),
+            "CURRENT-PROJECTION {{ message }}".to_string(),
+        );
+        let mut projection = crate::prompt::catalog::EffectivePromptCatalog::new(
+            templates,
+            2,
+            projection.schema_fingerprint.clone(),
+            projection.toolchain_fingerprint.clone(),
+        )
+        .unwrap();
+        projection.source_digest = "source-2".to_string();
+        prompts.store(Arc::new(
+            PromptCatalog::from_projection(projection).unwrap(),
+        ));
+
+        buffer.push_notify("updated".to_string(), false);
+        let appends = interceptor.pending_history_appends().await.unwrap();
+        assert_eq!(appends.len(), 1);
+        assert!(format!("{:?}", appends[0]).contains("CURRENT-PROJECTION updated"));
+    }
+
     #[tokio::test]
     async fn pending_history_appends_drains_buffer_into_items() {
         let registry = Arc::new(HookRegistryBuilder::new().build());
@@ -1046,7 +1091,7 @@ mod tests {
             None,
             buffer.clone(),
             Arc::new(Mutex::new(Vec::new())),
-            PromptCatalog::builtins_only().unwrap(),
+            test_prompts(),
             None,
         );
 
@@ -1083,7 +1128,7 @@ mod tests {
             None,
             buffer.clone(),
             Arc::new(Mutex::new(Vec::new())),
-            PromptCatalog::builtins_only().unwrap(),
+            test_prompts(),
             None,
         );
         let mut ctx: Vec<Item> = vec![Item::user_message("hi")];
@@ -1113,7 +1158,7 @@ mod tests {
             None,
             NotifyBuffer::new(),
             Arc::new(Mutex::new(Vec::new())),
-            PromptCatalog::builtins_only().unwrap(),
+            test_prompts(),
             None,
         );
         let mut ctx: Vec<Item> = Vec::new();
diff --git a/crates/worker/src/spawn/tool.rs b/crates/worker/src/spawn/tool.rs
index 17096356..26dae685 100644
--- a/crates/worker/src/spawn/tool.rs
+++ b/crates/worker/src/spawn/tool.rs
@@ -8,6 +8,7 @@
 use std::path::{Path, PathBuf};
 use std::sync::Arc;
 
+use arc_swap::ArcSwap;
 use async_trait::async_trait;
 use llm_engine::tool::{Tool, ToolDefinition, ToolError, ToolMeta, ToolOutput};
 use manifest::{
@@ -946,7 +947,7 @@ pub(crate) fn sub_worker_spawn_tool(
     registry: Arc<SpawnedWorkerRegistry>,
     spawner_manifest: WorkerManifest,
     spawner_scope: SharedScope,
-    prompts: Arc<PromptCatalog>,
+    prompts: Arc<ArcSwap<PromptCatalog>>,
 ) -> ToolDefinition {
     sub_worker_spawn_tool_impl(
         spawner_name,
@@ -972,13 +973,14 @@ fn sub_worker_spawn_tool_impl(
     registry: Arc<SpawnedWorkerRegistry>,
     spawner_manifest: WorkerManifest,
     spawner_scope: SharedScope,
-    prompts: Arc<PromptCatalog>,
+    prompts: Arc<ArcSwap<PromptCatalog>>,
 ) -> ToolDefinition {
     Arc::new(move || {
         let schema = schemars::schema_for!(SubWorkerSpawnInput);
         let schema_value = serde_json::to_value(schema).unwrap_or(serde_json::json!({}));
         let available_profiles = AvailableProfiles::discover(&workspace_root);
         let description = prompts
+            .load_full()
             .sub_worker_spawn_tool_description(
                 &available_profiles.compact_list(),
                 &available_profiles.default_label(),
@@ -1002,7 +1004,7 @@ fn sub_worker_spawn_tool_impl(
             spawner_cwd.clone(),
             registry.clone(),
             spawner_manifest.clone(),
-            prompts.source(),
+            prompts.load_full().source(),
             available_profiles,
             spawner_scope.clone(),
             DelegationScope::from_config(&spawner_manifest.delegation_scope)
diff --git a/crates/worker/src/worker.rs b/crates/worker/src/worker.rs
index 56be1b96..f7606b20 100644
--- a/crates/worker/src/worker.rs
+++ b/crates/worker/src/worker.rs
@@ -67,7 +67,7 @@ use crate::ipc::alerter::Alerter;
 use crate::ipc::interceptor::WorkerInterceptor;
 use crate::ipc::notify_buffer::NotifyBuffer;
 use crate::prompt::agents_md::read_agents_md;
-use crate::prompt::catalog::{CatalogError, PromptCatalog};
+use crate::prompt::catalog::{CatalogError, PromptCatalog, WorkspacePromptProjection};
 use crate::prompt::source::PromptCatalogSource;
 use crate::prompt::system::{SystemPromptContext, SystemPromptError, SystemPromptTemplate};
 use crate::runtime::dir;
@@ -224,6 +224,15 @@ pub trait WorkspaceClient: std::fmt::Debug + Send + Sync {
     fn execute(&self, request: WorkspaceRequest)
     -> Result<WorkspaceResponse, WorkspaceClientError>;
 
+    /// Resolve the Workspace's current immutable Prompt projection for future
+    /// operation boundaries. Creation and restore continue to use persisted
+    /// launch/session state; this hook never reconstructs historical prompts.
+    fn current_prompt_projection(
+        &self,
+    ) -> Result<Option<WorkspacePromptProjection>, WorkspaceClientError> {
+        Ok(None)
+    }
+
     /// Executes the destructive WorkerRemove operation through Runtime-owned source proof.
     /// Target identity is operation data; source identity and permission are never caller inputs.
     fn execute_worker_remove(
@@ -285,6 +294,12 @@ impl WorkspaceClient for ReviewerChildWorkspaceClient {
         Some(&self.context)
     }
 
+    fn current_prompt_projection(
+        &self,
+    ) -> Result<Option<WorkspacePromptProjection>, WorkspaceClientError> {
+        self.inner.current_prompt_projection()
+    }
+
     fn execute(
         &self,
         mut request: WorkspaceRequest,
@@ -872,7 +887,7 @@ pub struct Worker<C: LlmClient, St: Store> {
     /// sections, ...). Built from the 4-layer overlay in
     /// [`Self::from_manifest`], or defaults to the builtin pack when a
     /// Worker is constructed through lower-level paths that have no loader.
-    prompts: Arc<PromptCatalog>,
+    prompts: Arc<ArcSwap<PromptCatalog>>,
     /// When true (default), the system-prompt assembler may append resident
     /// context from the workspace Memory document. Internal disposable
     /// workers disable this so resident memory exposure is opt-in per Worker.
@@ -1146,7 +1161,7 @@ impl<C: LlmClient, St: Store> Worker<C, St> {
         // `set_system_prompt_template`) can be captured by `SegmentStart`.
         let session_id = session_store::new_session_id();
         let segment_id = session_store::new_segment_id();
-        let prompts = PromptCatalog::builtins_only()?;
+        let prompts = Arc::new(ArcSwap::from(PromptCatalog::builtins_only()?));
         let delegation_scope =
             DelegationScope::from_config(&manifest.delegation_scope).map_err(WorkerError::Scope)?;
         let scope = SharedScope::new(scope);
@@ -1232,10 +1247,49 @@ impl<C: LlmClient, St: Store> Worker<C, St> {
         self.inject_resident_summary = enabled;
     }
 
-    pub fn prompts(&self) -> Arc<PromptCatalog> {
+    pub fn prompts(&self) -> Arc<ArcSwap<PromptCatalog>> {
         Arc::clone(&self.prompts)
     }
 
+    fn refresh_prompt_projection_for_future_operations(&self) -> Result<(), WorkerError> {
+        // The launch catalog remains authoritative until the initial system
+        // Prompt has been rendered and committed. Later operation boundaries
+        // may adopt the Workspace's current immutable projection.
+        if self.system_prompt_template.is_some() {
+            return Ok(());
+        }
+        let Some(projection) = self
+            .workspace_context
+            .client()
+            .current_prompt_projection()
+            .map_err(|source| WorkerError::WorkspacePromptProjection {
+                message: source.to_string(),
+            })?
+        else {
+            return Ok(());
+        };
+        projection
+            .validate()
+            .map_err(|source| WorkerError::WorkspacePromptProjection {
+                message: source.to_string(),
+            })?;
+        let current = self.prompts.load();
+        if current.projection().config_revision == projection.config_revision
+            && current.projection().source_digest == projection.source_digest
+            && current.projection().catalog_digest == projection.projection_digest
+        {
+            return Ok(());
+        }
+        let catalog = PromptCatalog::load(
+            &PromptCatalogSource::builtins_only().with_effective_catalog(projection.catalog),
+        )
+        .map_err(|source| WorkerError::WorkspacePromptProjection {
+            message: source.to_string(),
+        })?;
+        self.prompts.store(catalog);
+        Ok(())
+    }
+
     /// The current segment ID. Read lock-free from the shared session
     /// pointer so fork-time swaps are observed immediately.
     pub fn segment_id(&self) -> SegmentId {
@@ -2020,6 +2074,7 @@ impl<C: LlmClient, St: Store> Worker<C, St> {
             .local_working_directory()
             .map(|local| local.cwd.display().to_string())
             .unwrap_or_else(|| "no local working directory".to_string());
+        let prompt_catalog = self.prompts.load_full();
         let ctx = SystemPromptContext {
             now: chrono::Utc::now(),
             cwd: cwd_for_prompt.into(),
@@ -2029,7 +2084,7 @@ impl<C: LlmClient, St: Store> Worker<C, St> {
             feature_instructions: &self.feature_instructions,
             agents_md: agents_md_read.and_then(|read| read.body),
             resident_summary: resident_summary.as_deref(),
-            prompts: &self.prompts,
+            prompts: &prompt_catalog,
         };
         let rendered = template
             .render(&ctx)
@@ -2085,6 +2140,7 @@ impl<C: LlmClient, St: Store> Worker<C, St> {
     /// store, and runs pre-run compact (joining any in-flight memory task
     /// first so extract sees a stable history range).
     async fn prepare_for_run(&mut self) -> Result<(), WorkerError> {
+        self.refresh_prompt_projection_for_future_operations()?;
         self.ensure_interceptor_installed();
         self.ensure_system_prompt_materialized().await?;
         self.cleanup_finished_memory_task();
@@ -2430,10 +2486,12 @@ impl<C: LlmClient, St: Store> Worker<C, St> {
     fn apply_interrupt_prep(&mut self) -> Result<(), WorkerError> {
         let tool_result_summary = self
             .prompts()
+            .load_full()
             .interrupt_tool_result_summary()
             .map_err(WorkerError::from)?;
         let system_note = self
             .prompts()
+            .load_full()
             .interrupt_system_note()
             .map_err(WorkerError::from)?;
 
@@ -3173,6 +3231,7 @@ impl<C: LlmClient, St: Store> Worker<C, St> {
         let summary_client: Box<dyn LlmClient> = self.build_compactor_client()?;
         let summary_system_prompt = self
             .prompts
+            .load_full()
             .compact_system()
             .map_err(WorkerError::PromptCatalog)?;
         let mut summary_worker = Engine::new(summary_client).system_prompt(summary_system_prompt);
@@ -3802,7 +3861,11 @@ impl<C: LlmClient, St: Store> Worker<C, St> {
             }
         };
         let memory_language = memory_language(memory_cfg);
-        let extract_system_prompt = match self.prompts.memory_extract_system(memory_language) {
+        let extract_system_prompt = match self
+            .prompts
+            .load_full()
+            .memory_extract_system(memory_language)
+        {
             Ok(prompt) => prompt,
             Err(err) => {
                 audit
@@ -5446,6 +5509,9 @@ pub enum WorkerError {
     #[error(transparent)]
     PromptCatalog(#[from] CatalogError),
 
+    #[error("failed to resolve current Workspace Prompt projection: {message}")]
+    WorkspacePromptProjection { message: String },
+
     #[error(transparent)]
     Skill(#[from] SkillClientError),
 
@@ -5513,7 +5579,7 @@ struct WorkerCommon {
     scope: Scope,
     delegation_scope: DelegationScope,
     client: Box<dyn LlmClient>,
-    prompts: Arc<PromptCatalog>,
+    prompts: Arc<ArcSwap<PromptCatalog>>,
     system_prompt_template: Option<SystemPromptTemplate>,
     feature_instructions: Vec<FeatureInstructionDeclaration>,
 }
@@ -5655,7 +5721,7 @@ fn prepare_worker_common_from_scope(
         DelegationScope::from_config(&manifest.delegation_scope).map_err(WorkerError::Scope)?;
 
     let client = crate::model_client::build_client(&manifest.model)?;
-    let prompts = PromptCatalog::load(loader)?;
+    let prompts = Arc::new(ArcSwap::from(PromptCatalog::load(loader)?));
     let system_prompt_template = if parse_template {
         Some(
             SystemPromptTemplate::parse(&manifest.engine.instruction, loader.clone())