diff --git a/backend/app/schemas/script_builder.py b/backend/app/schemas/script_builder.py
index 1a7add15..430022c8 100644
--- a/backend/app/schemas/script_builder.py
+++ b/backend/app/schemas/script_builder.py
@@ -1,18 +1,27 @@
 """Pydantic schemas for the AI Script Builder."""
 from datetime import datetime
-from typing import Optional
+from typing import Literal, Optional
 from uuid import UUID
 
 from pydantic import BaseModel, Field
 
 
 class ScriptBuilderCreateRequest(BaseModel):
-    """Request to start a new builder session."""
+    """Request to start (or get-or-create, for inline origin) a builder session.
+
+    When `origin='pilot_inline'`, `ai_session_id` is REQUIRED and must
+    reference a pilot session owned by the current user. The endpoint's
+    get-or-create semantics kick in: if a pilot_inline session already
+    exists for (user_id, ai_session_id), that row is returned instead of
+    creating a duplicate.
+    """
     language: str = Field(
         default="powershell",
         pattern=r"^(powershell|bash|python)$",
         description="Script language",
     )
+    origin: Literal["standalone", "pilot_inline"] = "standalone"
+    ai_session_id: UUID | None = None
 
 
 class ScriptBuilderMessageRequest(BaseModel):
diff --git a/backend/app/schemas/session_suggested_fix.py b/backend/app/schemas/session_suggested_fix.py
index 38f380b5..2672c764 100644
--- a/backend/app/schemas/session_suggested_fix.py
+++ b/backend/app/schemas/session_suggested_fix.py
@@ -114,6 +114,17 @@ class SessionSuggestedFixOutcomeRequest(BaseModel):
     notes: str | None = Field(None, max_length=500)
 
 
+class SessionSuggestedFixScriptRequest(BaseModel):
+    """Engineer-submitted drafted script for a suggested fix.
+
+    Called when the inline Script Builder tab's Submit action fires. The
+    fix must be non-terminal (still proposed/applied_partial). Setting
+    the script does NOT stamp applied_at — a draft is not an application.
+    """
+    ai_drafted_script: str = Field(..., min_length=1, max_length=50_000)
+    ai_drafted_parameters: dict[str, Any] | None = None
+
+
 # ── Resolution note preview ────────────────────────────────────────────────
 
 class ResolutionNotePreviewResponse(BaseModel):