api: convert tool_input JSON to YAML in execution log response

src/api/workflows.rs

@@ -82,6 +82,29 @@ async fn create_workflow(
     Ok(Json(workflow))
 }
 
+/// Convert a JSON string to a simple YAML-like representation for display.
+/// Falls back to the original string if it's not a JSON object.
+fn json_to_yaml(input: &str) -> String {
+    let obj: serde_json::Map<String, serde_json::Value> = match serde_json::from_str(input) {
+        Ok(v) => v,
+        Err(_) => return input.to_string(),
+    };
+    let mut lines = Vec::new();
+    for (k, v) in &obj {
+        match v {
+            serde_json::Value::String(s) if s.contains('\n') => {
+                lines.push(format!("{}: |", k));
+                for line in s.lines() {
+                    lines.push(format!("  {}", line));
+                }
+            }
+            serde_json::Value::String(s) => lines.push(format!("{}: {}", k, s)),
+            other => lines.push(format!("{}: {}", k, other)),
+        }
+    }
+    lines.join("\n")
+}
+
 async fn list_steps(
     State(state): State<Arc<AppState>>,
     Path(workflow_id): Path<String>,
@@ -92,7 +115,10 @@ async fn list_steps(
     .bind(&workflow_id)
     .fetch_all(&state.db.pool)
     .await
-    .map(Json)
+    .map(|entries| Json(entries.into_iter().map(|mut e| {
+        e.tool_input = json_to_yaml(&e.tool_input);
+        e
+    }).collect()))
     .map_err(db_err)
 }