Add flow-control data to STAGE_COMPLETED event

Add status, preferred_label, and suggested_next_ids fields to the
StageCompleted event so pipeline flow decisions are visible in CLI
output and the web UI, making it easier to debug why a pipeline
took a particular path.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

attractor-web/src/EventLog.tsx

@@ -30,8 +30,11 @@ function eventDetail(event: PipelineEvent): string {
       return `${data.error} (${data.duration_ms}ms)`;
     case "StageStarted":
       return `${data.name} [${data.index}]`;
-    case "StageCompleted":
-      return `${data.name} [${data.index}] ${data.duration_ms}ms`;
+    case "StageCompleted": {
+      let detail = `${data.name} [${data.index}] ${data.duration_ms}ms ${data.status}`;
+      if (data.preferred_label) detail += ` → "${data.preferred_label}"`;
+      return detail;
+    }
     case "StageFailed":
       return `${data.name} [${data.index}]: ${data.error}${data.will_retry ? " (will retry)" : ""}`;
     case "StageRetrying":

attractor-web/src/api.ts

@@ -54,7 +54,7 @@ export type PipelineEvent =
   | { PipelineCompleted: { duration_ms: number; artifact_count: number } }
   | { PipelineFailed: { error: string; duration_ms: number } }
   | { StageStarted: { name: string; index: number } }
-  | { StageCompleted: { name: string; index: number; duration_ms: number } }
+  | { StageCompleted: { name: string; index: number; duration_ms: number; status: string; preferred_label?: string; suggested_next_ids: string[] } }
   | { StageFailed: { name: string; index: number; error: string; will_retry: boolean } }
   | { StageRetrying: { name: string; index: number; attempt: number; delay_ms: number } }
   | { ParallelStarted: { branch_count: number } }

crates/attractor/src/cli/mod.rs

@@ -164,8 +164,18 @@ pub fn format_event_summary(event: &PipelineEvent, styles: &Styles) -> String {
             name,
             index,
             duration_ms,
+            status,
+            preferred_label,
+            suggested_next_ids,
         } => {
-            format!("[STAGE_COMPLETED] name={name} index={index} duration={duration_ms}ms")
+            let mut s = format!("[STAGE_COMPLETED] name={name} index={index} duration={duration_ms}ms status={status}");
+            if let Some(label) = preferred_label {
+                s.push_str(&format!(" preferred_label=\"{label}\""));
+            }
+            if !suggested_next_ids.is_empty() {
+                s.push_str(&format!(" suggested_next_ids={}", suggested_next_ids.join(",")));
+            }
+            s
         }
         PipelineEvent::StageFailed {
             name,
@@ -263,8 +273,18 @@ pub fn format_event_detail(event: &PipelineEvent, styles: &Styles) -> String {
             name,
             index,
             duration_ms,
+            status,
+            preferred_label,
+            suggested_next_ids,
         } => {
-            format!("{d}── STAGE_COMPLETED ──────────────────────────{r}\n  {d}name:{r}        {name}\n  {d}index:{r}       {index}\n  {d}duration_ms:{r} {duration_ms}\n")
+            let mut s = format!("{d}── STAGE_COMPLETED ──────────────────────────{r}\n  {d}name:{r}        {name}\n  {d}index:{r}       {index}\n  {d}duration_ms:{r} {duration_ms}\n  {d}status:{r}      {status}\n");
+            if let Some(label) = preferred_label {
+                s.push_str(&format!("  {d}preferred_label:{r} {label}\n"));
+            }
+            if !suggested_next_ids.is_empty() {
+                s.push_str(&format!("  {d}suggested_next_ids:{r} {}\n", suggested_next_ids.join(", ")));
+            }
+            s
         }
         PipelineEvent::StageFailed {
             name,

crates/attractor/src/event.rs

@@ -23,6 +23,9 @@ pub enum PipelineEvent {
         name: String,
         index: usize,
         duration_ms: u64,
+        status: String,
+        preferred_label: Option<String>,
+        suggested_next_ids: Vec<String>,
     },
     StageFailed {
         name: String,