Schema + executor: accept string shorthand for on_failure, edit_file returns content

work_block_schema.py: _FAILURE_HANDLER now uses oneOf — accepts both string
shorthands ("abort", "skip", "continue", etc.) and the full object form
{"action": "abort_block"}. Easier spec authoring without breaking existing specs.

spec_executor.py: _handle_failure normalizes string shorthands to dict at
entry so execution works regardless of which form the spec uses.

spec_executor.py: edit_file in _direct_filesystem_op now returns new file
content instead of a confirmation string, enabling contains/not_contains
validation checks on the result of an edit.

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

spec_executor.py

@@ -409,7 +409,7 @@ class SpecExecutor:
                 return {"status": "error", "error": f"old_text found {count} times in {path} — must be unique"}
             new_content = content.replace(old_text, new_text, 1)
             target.write_text(new_content, encoding="utf-8")
-            return f"Edited {target} — replaced 1 occurrence ({len(new_content):,} bytes)"
+            return new_content
 
         elif tool_name == "shell_execute":
             import subprocess as _sp
@@ -504,7 +504,19 @@ class SpecExecutor:
     # Failure handling
     # ------------------------------------------------------------------
 
-    def _handle_failure(self, handler: dict, step_id: str, ctx: ExecutionContext):
+    def _handle_failure(self, handler, step_id: str, ctx: ExecutionContext):
+        # Normalize string shorthand (e.g. "abort", "skip") to full dict form.
+        if isinstance(handler, str):
+            _shorthand_map = {
+                "abort": "abort_block",
+                "abort_block": "abort_block",
+                "continue": "skip",
+                "skip": "skip",
+                "retry": "retry",
+                "goto": "goto",
+                "escalate_to_qb": "escalate_to_qb",
+            }
+            handler = {"action": _shorthand_map.get(handler, "abort_block")}
         action = handler["action"]
         msg = handler.get("message", f"Step {step_id} failed")
 

work_block_schema.py

@@ -64,16 +64,28 @@ _CONDITION_CHECK = {
     },
 }
 
+# String shorthands accepted in on_failure for easier spec authoring.
+# Executor normalizes these to the full object form before acting on them.
+_FAILURE_SHORTHANDS = ["abort", "abort_block", "continue", "skip", "retry", "goto", "escalate_to_qb"]
+
 _FAILURE_HANDLER = {
-    "type": "object",
-    "required": ["action"],
-    "additionalProperties": False,
-    "properties": {
-        "action": {"enum": _FAILURE_ACTIONS},
-        "max_retries": {"type": "integer", "minimum": 0, "default": 0},
-        "goto_step": {"type": "string"},
-        "message": {"type": "string"},
-    },
+    "oneOf": [
+        {
+            "type": "string",
+            "enum": _FAILURE_SHORTHANDS,
+        },
+        {
+            "type": "object",
+            "required": ["action"],
+            "additionalProperties": False,
+            "properties": {
+                "action": {"enum": _FAILURE_ACTIONS},
+                "max_retries": {"type": "integer", "minimum": 0, "default": 0},
+                "goto_step": {"type": "string"},
+                "message": {"type": "string"},
+            },
+        },
+    ]
 }
 
 _VALIDATION_BLOCK = {