feat: add raw session args/opts for agent passthrough

docs/openapi.json

@@ -669,7 +669,9 @@
           "mcpTools",
           "streamingDeltas",
           "itemStarted",
-          "sharedProcess"
+          "sharedProcess",
+          "rawSessionArgs",
+          "rawSessionOptions"
         ],
         "properties": {
           "commandExecution": {
@@ -702,6 +704,14 @@
           "questions": {
             "type": "boolean"
           },
+          "rawSessionArgs": {
+            "type": "boolean",
+            "description": "Whether this agent supports raw CLI arguments passed at session creation"
+          },
+          "rawSessionOptions": {
+            "type": "boolean",
+            "description": "Whether this agent supports raw options passed at session creation"
+          },
           "reasoning": {
             "type": "boolean"
           },
@@ -1074,6 +1084,20 @@
           "variant": {
             "type": "string",
             "nullable": true
+          },
+          "rawSessionArgs": {
+            "type": "array",
+            "items": {
+              "type": "string"
+            },
+            "nullable": true,
+            "description": "Raw CLI arguments to pass to the agent (for CLI-based agents like Claude, OpenCode, Amp)"
+          },
+          "rawSessionOptions": {
+            "type": "object",
+            "additionalProperties": true,
+            "nullable": true,
+            "description": "Raw options to pass to the agent (for long-running server agents like Codex)"
           }
         }
       },