Use native S-expression for recipe/plan display

- Display recipe's original S-expression when available (code is data)
- Fall back to generating S-expression from plan for legacy JSON
- Run service now prefers .sexp plan files over .json
- Add get_run_plan_sexp() for direct S-expression access

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

app/routers/runs.py

@@ -178,6 +178,7 @@ async def get_run(
 
         # Try to load the recipe to show the plan
         plan = None
+        plan_sexp = None  # Native S-expression if available
         recipe_id = run.get("recipe")
         if recipe_id and len(recipe_id) == 64:  # Looks like a hash
             try:
@@ -185,7 +186,11 @@ async def get_run(
                 recipe_service = RecipeService(get_redis_client(), get_cache_manager())
                 recipe = await recipe_service.get_recipe(recipe_id)
                 if recipe:
-                    # Use the new build_dag method if available
+                    # Use native S-expression if available (code is data!)
+                    if recipe.get("sexp"):
+                        plan_sexp = recipe["sexp"]
+
+                    # Build steps for DAG visualization
                     dag = recipe.get("dag", {})
                     nodes = dag.get("nodes", [])
 
@@ -311,8 +316,9 @@ async def get_run(
                             }
                         })
 
-        # Generate S-expression representation of the plan
-        plan_sexp = plan_to_sexp(plan, run.get("recipe_name"))
+        # Use native S-expression if available, otherwise generate from plan
+        if not plan_sexp and plan:
+            plan_sexp = plan_to_sexp(plan, run.get("recipe_name"))
 
         templates = get_templates(request)
         return render(templates, "runs/detail.html", request,

app/services/run_service.py

@@ -482,10 +482,28 @@ class RunService:
 
     async def get_run_plan(self, run_id: str) -> Optional[Dict[str, Any]]:
         """Get execution plan for a run."""
-        plan_path = self.cache_dir / "plans" / f"{run_id}.json"
-        if plan_path.exists():
-            with open(plan_path) as f:
-                return json.load(f)
+        # Prefer S-expression plan
+        sexp_path = self.cache_dir / "plans" / f"{run_id}.sexp"
+        if sexp_path.exists():
+            with open(sexp_path) as f:
+                return {"sexp": f.read(), "format": "sexp"}
+
+        # Fall back to JSON for legacy plans
+        json_path = self.cache_dir / "plans" / f"{run_id}.json"
+        if json_path.exists():
+            with open(json_path) as f:
+                plan = json.load(f)
+                plan["format"] = "json"
+                return plan
+
+        return None
+
+    async def get_run_plan_sexp(self, run_id: str) -> Optional[str]:
+        """Get execution plan as S-expression string."""
+        sexp_path = self.cache_dir / "plans" / f"{run_id}.sexp"
+        if sexp_path.exists():
+            with open(sexp_path) as f:
+                return f.read()
         return None
 
     async def get_run_artifacts(self, run_id: str) -> List[Dict[str, Any]]:

app/templates/runs/detail.html

@@ -156,15 +156,17 @@
             {% endfor %}
         </div>
 
-        <!-- Plan S-expression -->
+        <!-- Recipe/Plan S-expression -->
+        {% if plan_sexp %}
         <details class="mt-6" open>
             <summary class="cursor-pointer text-gray-400 hover:text-white text-sm mb-2">
-                Plan (S-expression)
+                Recipe (S-expression)
             </summary>
             <div class="bg-gray-900 rounded-lg border border-gray-700 p-4 overflow-x-auto">
                 <pre class="text-sm font-mono sexp-code">{{ plan_sexp }}</pre>
             </div>
         </details>
+        {% endif %}
 
         <style>
         .sexp-code {