Fix --dry-run executing command/script nodes instead of simulating them

Command nodes were running for real during dry-run mode because the
dry_run flag only affected LLM-backed handlers. Propagate dry_run
through EngineServices so CommandHandler can skip execution and return
a simulated success.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

lib/crates/fabro-workflows/src/cli/run.rs

@@ -1133,6 +1133,9 @@ pub async fn run_command(
     if !sandbox_env.is_empty() {
         engine.set_env(sandbox_env);
     }
+    if dry_run_mode {
+        engine.set_dry_run(true);
+    }
 
     // Wire up hook runner from run config or run defaults
     {
@@ -1769,12 +1772,15 @@ async fn run_from_branch(
             Some(Box::new(BackendRouter::new(Box::new(api), cli)))
         }
     });
-    let engine = crate::engine::WorkflowRunEngine::with_interviewer(
+    let mut engine = crate::engine::WorkflowRunEngine::with_interviewer(
         registry,
         Arc::clone(&emitter),
         interviewer,
         Arc::clone(&sandbox),
     );
+    if dry_run_mode {
+        engine.set_dry_run(true);
+    }
 
     let meta_branch = Some(crate::git::MetadataStore::branch_name(&run_id));
     let config = RunConfig {

lib/crates/fabro-workflows/src/engine.rs

@@ -832,6 +832,7 @@ impl WorkflowRunEngine {
                 git_state: std::sync::RwLock::new(None),
                 hook_runner: None,
                 env: HashMap::new(),
+                dry_run: false,
             },
             interviewer: None,
         }
@@ -848,6 +849,7 @@ impl WorkflowRunEngine {
                 git_state: std::sync::RwLock::new(None),
                 hook_runner: services.hook_runner.clone(),
                 env: services.env.clone(),
+                dry_run: services.dry_run,
             },
             interviewer: None,
         }
@@ -869,6 +871,7 @@ impl WorkflowRunEngine {
                 git_state: std::sync::RwLock::new(None),
                 hook_runner: None,
                 env: HashMap::new(),
+                dry_run: false,
             },
             interviewer: Some(interviewer),
         }
@@ -884,6 +887,11 @@ impl WorkflowRunEngine {
         self.services.env = env;
     }
 
+    /// Enable dry-run mode so handlers skip real execution.
+    pub fn set_dry_run(&mut self, dry_run: bool) {
+        self.services.dry_run = dry_run;
+    }
+
     /// Run lifecycle hooks and return the merged decision.
     /// Returns `Proceed` if no hook runner is configured.
     async fn run_hooks(&self, hook_context: &HookContext, work_dir: Option<&Path>) -> HookDecision {

lib/crates/fabro-workflows/src/handler/agent.rs

@@ -360,6 +360,7 @@ mod tests {
             git_state: std::sync::RwLock::new(None),
             hook_runner: None,
             env: HashMap::new(),
+            dry_run: false,
         }
     }
 
@@ -497,6 +498,7 @@ mod tests {
             git_state: std::sync::RwLock::new(None),
             hook_runner: None,
             env: HashMap::new(),
+            dry_run: false,
         };
 
         let outcome = handler
@@ -561,6 +563,7 @@ mod tests {
             git_state: std::sync::RwLock::new(None),
             hook_runner: None,
             env: HashMap::new(),
+            dry_run: false,
         };
 
         let outcome = handler
@@ -626,6 +629,7 @@ mod tests {
             git_state: std::sync::RwLock::new(None),
             hook_runner: None,
             env: HashMap::new(),
+            dry_run: false,
         };
 
         let outcome = handler

lib/crates/fabro-workflows/src/handler/command.rs

@@ -46,6 +46,18 @@ impl Handler for CommandHandler {
             return Ok(Outcome::fail_classify("No script specified"));
         }
 
+        if services.dry_run {
+            let mut outcome = Outcome::success();
+            outcome.notes = Some(format!("[Simulated] Command skipped: {script}"));
+            outcome
+                .context_updates
+                .insert(keys::COMMAND_OUTPUT.to_string(), serde_json::json!(""));
+            outcome
+                .context_updates
+                .insert(keys::COMMAND_STDERR.to_string(), serde_json::json!(""));
+            return Ok(outcome);
+        }
+
         let language = node
             .attrs
             .get("language")
@@ -168,6 +180,7 @@ mod tests {
             git_state: std::sync::RwLock::new(None),
             hook_runner: None,
             env: std::collections::HashMap::new(),
+            dry_run: false,
         }
     }
 
@@ -187,6 +200,33 @@ mod tests {
         assert_eq!(outcome.failure_reason(), Some("No script specified"));
     }
 
+    #[tokio::test]
+    async fn dry_run_skips_execution() {
+        let handler = CommandHandler;
+        let mut node = Node::new("script_node");
+        node.attrs.insert(
+            "script".to_string(),
+            AttrValue::String("echo hello".to_string()),
+        );
+        let context = Context::new();
+        let graph = Graph::new("test");
+        let run_dir = tempfile::tempdir().unwrap();
+
+        let mut services = make_services();
+        services.dry_run = true;
+
+        let outcome = handler
+            .execute(&node, &context, &graph, run_dir.path(), &services)
+            .await
+            .unwrap();
+        assert_eq!(outcome.status, StageStatus::Success);
+        assert!(outcome.notes.as_deref().unwrap().contains("[Simulated]"));
+        assert!(outcome.notes.as_deref().unwrap().contains("echo hello"));
+        // No stdout/stderr logs should be written
+        let stage_dir = run_dir.path().join("nodes").join("script_node");
+        assert!(!stage_dir.join("stdout.log").exists());
+    }
+
     #[tokio::test]
     async fn script_handler_echo_command() {
         let handler = CommandHandler;
@@ -678,6 +718,7 @@ mod tests {
             git_state: std::sync::RwLock::new(None),
             hook_runner: None,
             env: std::collections::HashMap::new(),
+            dry_run: false,
         }
     }
 

lib/crates/fabro-workflows/src/handler/conditional.rs

@@ -46,6 +46,7 @@ mod tests {
             git_state: std::sync::RwLock::new(None),
             hook_runner: None,
             env: std::collections::HashMap::new(),
+            dry_run: false,
         }
     }
 

lib/crates/fabro-workflows/src/handler/exit.rs

@@ -43,6 +43,7 @@ mod tests {
             git_state: std::sync::RwLock::new(None),
             hook_runner: None,
             env: std::collections::HashMap::new(),
+            dry_run: false,
         }
     }
 

lib/crates/fabro-workflows/src/handler/fan_in.rs

@@ -299,6 +299,7 @@ mod tests {
             git_state: std::sync::RwLock::new(None),
             hook_runner: None,
             env: std::collections::HashMap::new(),
+            dry_run: false,
         }
     }
 

lib/crates/fabro-workflows/src/handler/human.rs

@@ -301,6 +301,7 @@ mod tests {
             git_state: std::sync::RwLock::new(None),
             hook_runner: None,
             env: std::collections::HashMap::new(),
+            dry_run: false,
         }
     }
 

lib/crates/fabro-workflows/src/handler/manager_loop.rs

@@ -141,7 +141,7 @@ impl Handler for SubWorkflowHandler {
         let child_config = RunConfig {
             run_dir: child_logs,
             cancel_token: Some(cancel_token),
-            dry_run: false,
+            dry_run: services.dry_run,
             run_id: format!("{parent_run_id}_child_{}", node.id),
             git_checkpoint_enabled: false,
             host_repo_path: None,
@@ -274,6 +274,7 @@ mod tests {
             git_state: std::sync::RwLock::new(None),
             hook_runner: None,
             env: HashMap::new(),
+            dry_run: false,
         }
     }
 
@@ -407,6 +408,7 @@ mod tests {
             git_state: std::sync::RwLock::new(None),
             hook_runner: None,
             env: HashMap::new(),
+            dry_run: false,
         };
 
         let handler = SubWorkflowHandler;
@@ -516,6 +518,7 @@ mod tests {
             git_state: std::sync::RwLock::new(None),
             hook_runner: None,
             env: HashMap::new(),
+            dry_run: false,
         };
 
         let handler = SubWorkflowHandler;
@@ -577,6 +580,7 @@ mod tests {
             git_state: std::sync::RwLock::new(None),
             hook_runner: None,
             env: HashMap::new(),
+            dry_run: false,
         };
 
         let handler = SubWorkflowHandler;
@@ -744,6 +748,7 @@ mod tests {
             git_state: std::sync::RwLock::new(None),
             hook_runner: None,
             env: HashMap::new(),
+            dry_run: false,
         };
 
         let handler = SubWorkflowHandler;
@@ -828,6 +833,7 @@ mod tests {
             git_state: std::sync::RwLock::new(None),
             hook_runner: None,
             env: HashMap::new(),
+            dry_run: false,
         };
 
         let handler = SubWorkflowHandler;

lib/crates/fabro-workflows/src/handler/mod.rs

@@ -38,6 +38,8 @@ pub struct EngineServices {
     pub hook_runner: Option<Arc<HookRunner>>,
     /// Environment variables from `[sandbox.env]` config, injected into command nodes.
     pub env: HashMap<String, String>,
+    /// When true, handlers should skip real execution and return simulated results.
+    pub dry_run: bool,
 }
 
 impl EngineServices {

lib/crates/fabro-workflows/src/handler/parallel.rs

@@ -384,6 +384,7 @@ impl Handler for ParallelHandler {
             let emitter = Arc::clone(&services.emitter);
             let hook_runner = services.hook_runner.clone();
             let env = services.env.clone();
+            let dry_run = services.dry_run;
             let graph = graph.clone();
             let run_dir = run_dir.to_path_buf();
             let sem = Arc::clone(&semaphore);
@@ -432,6 +433,7 @@ impl Handler for ParallelHandler {
                     git_state: std::sync::RwLock::new(None),
                     hook_runner: hook_runner.clone(),
                     env: env.clone(),
+                    dry_run,
                 };
                 let handler = registry.resolve(target_node);
                 let outcome = handler
@@ -742,6 +744,7 @@ mod tests {
             git_state: std::sync::RwLock::new(None),
             hook_runner: None,
             env: std::collections::HashMap::new(),
+            dry_run: false,
         }
     }
 

lib/crates/fabro-workflows/src/handler/prompt.rs

@@ -164,6 +164,7 @@ mod tests {
             git_state: std::sync::RwLock::new(None),
             hook_runner: None,
             env: std::collections::HashMap::new(),
+            dry_run: false,
         }
     }
 

lib/crates/fabro-workflows/src/handler/start.rs

@@ -42,6 +42,7 @@ mod tests {
             git_state: std::sync::RwLock::new(None),
             hook_runner: None,
             env: std::collections::HashMap::new(),
+            dry_run: false,
         }
     }
 

lib/crates/fabro-workflows/src/handler/wait.rs

@@ -57,6 +57,7 @@ mod tests {
             git_state: std::sync::RwLock::new(None),
             hook_runner: None,
             env: std::collections::HashMap::new(),
+            dry_run: false,
         }
     }