Fix create_skill wedge: short-circuit single-option navigation, never leave scheduler busy

An empty category produced a one-option SemIf leaf decision; the backend rejects
<2 options, the ValueError unwound past the current-process reset, and every
later request queued forever behind a phantom current. Navigation now
short-circuits empty trees/categories straight to the create branch (no SemIf
decision when there's nothing to choose), and the scheduler clears its current
process even when dispatch raises. Authoring generation is capped at 128 tokens.

semif_agent/scheduler.py

@@ -152,8 +152,10 @@ class Scheduler:
         if self.current is None:
             weight, label = self._score(request)
             self.current = Process(request=request, skill="(scheduling)", weight=weight)
-            outcome = self._dispatch(request)
-            self.current = None
+            try:
+                outcome = self._dispatch(request)
+            finally:
+                self.current = None
             self.trace.append("ran", request.id, skill=outcome.skill, summary=outcome.summary)
             return "running", f"[{label}] {outcome.summary}"
 
@@ -197,7 +199,11 @@ class Scheduler:
                 outcome = self._dispatch(request)
             except EngineUnavailable as exc:
                 outcome = DispatchResult(kind="error", summary=f"engine unavailable: {exc}")
-            self.current = None
+            except Exception as exc:
+                self.trace.append("error", request.id, phase="dispatch", message=str(exc))
+                outcome = DispatchResult(kind="error", summary=f"dispatch failed: {exc}")
+            finally:
+                self.current = None
             self.trace.append("ran", request.id, skill=outcome.skill, summary=outcome.summary)
             results.append(("ran", f"[{request.id}] {outcome.summary}"))
         return results

semif_agent/skills.py

@@ -262,7 +262,10 @@ def navigate(
 
     The category level offers a "create_category" branch and the leaf level a
     "create_skill" branch; both are handled live by dispatch and log a
-    suggestion event to the trace.
+    suggestion event to the trace. A level with nothing to choose from
+    (an empty tree, or a category with no skills yet) short-circuits straight to
+    the create branch: SemIf decisions need at least two options, and asking
+    "which of one?" is meaningless.
     """
     categories = sorted(tree.keys())
     create_category = Option("create_category", "Suggest a new category for this.")
@@ -271,6 +274,17 @@ def navigate(
         question="Which top-level category handles this request?",
         options=[Option(c, c) for c in categories] + [create_category],
     )
+    if not categories:
+        trace.append(
+            "create_category",
+            request.id,
+            state=top.state,
+            question=top.question,
+            options=[o.id for o in top.options],
+            selected="create_category",
+            probs={},
+        )
+        return CreateCategory()
     top_result = engine.call(top)
     log.append(top, top_result, extra={"phase": "navigate:category", "run_id": request.id})
     category = top_result.selected
@@ -292,6 +306,18 @@ def navigate(
         question=f"Within {category}, which skill?",
         options=[Option(s.name, s.description) for s in skills] + [create_skill],
     )
+    if not skills:
+        trace.append(
+            "skill_needed",
+            request.id,
+            category=category,
+            state=leaf.state,
+            question=leaf.question,
+            options=[o.id for o in leaf.options],
+            selected="create_skill",
+            probs={},
+        )
+        return CreateSkill(category=category)
     leaf_result = engine.call(leaf)
     log.append(leaf, leaf_result, extra={"phase": "navigate:leaf", "run_id": request.id})
     pick = leaf_result.selected
@@ -362,7 +388,7 @@ def generate_category(
     engine: SemIfEngine, request: Request, tree: dict[str, list[Skill]]
 ) -> CategoryDraft:
     """Author a new category stub with the decision model in generation mode."""
-    raw = engine.generate(build_category_prompt(request, tree))
+    raw = engine.generate(build_category_prompt(request, tree), max_tokens=128)
     return parse_category_draft(raw)
 
 
@@ -413,5 +439,5 @@ def generate_skill(
     engine: SemIfEngine, request: Request, category: str, tree: dict[str, list[Skill]]
 ) -> SkillDraft:
     """Author a new skill leaf stub with the decision model in generation mode."""
-    raw = engine.generate(build_skill_prompt(request, category, tree))
+    raw = engine.generate(build_skill_prompt(request, category, tree), max_tokens=128)
     return parse_skill_draft(raw)