fix: align ICodexTransport protocol signature with executor call site

The initiate_streaming_request protocol was missing keyword arguments
(context, backend, model, key_name) that the executor was passing.
This caused runtime failures for custom transport implementations.

Removed the cast(Any, self._transport) workaround that was suppressing
the type error.

Author: Mateusz

src/connectors/openai_codex/executor.py

@@ -454,17 +454,17 @@ async def _streaming_iterator() -> AsyncIterator[ProcessedResponse]:
                         attempt=attempts_used + 1,
                     )
                     try:
-                        stream_handle = await cast(
-                            Any, self._transport
-                        ).initiate_streaming_request(
-                            url,
-                            current_payload_dict,
-                            current_headers,
-                            context.session_id,
-                            context=request_context,
-                            backend="openai-codex",
-                            model=context.effective_model,
-                            key_name=capture_key_name,
+                        stream_handle = (
+                            await self._transport.initiate_streaming_request(
+                                url,
+                                current_payload_dict,
+                                current_headers,
+                                context.session_id,
+                                context=request_context,
+                                backend="openai-codex",
+                                model=context.effective_model,
+                                key_name=capture_key_name,
+                            )
                         )
                         # Fall through to consume the stream iterator below
                     except (HTTPException, LLMProxyError) as exc:
@@ -1082,6 +1082,8 @@ def _slice_input_for_continuation(
                 break
             common_prefix_len += 1
 
+        if common_prefix_len < len(prior_fingerprints):
+            return None
         if common_prefix_len <= 0 or common_prefix_len >= len(current_input):
             return None
         return list(current_input[common_prefix_len:])

src/connectors/openai_codex/interfaces.py

@@ -7,16 +7,17 @@
 
 from __future__ import annotations
 
-from abc import ABC, abstractmethod
-from collections.abc import Mapping
-from pathlib import Path
-from typing import Any, Protocol
-
-from src.connectors._openai_codex_capabilities import CodexClientCapabilities
-from src.connectors.openai_codex.contracts import (
-    CodexConnectorSettings,
-    CodexInputItem,
-    CodexPayload,
+from abc import ABC, abstractmethod
+from collections.abc import Mapping
+from pathlib import Path
+from typing import Any, Protocol
+
+from src.connectors._openai_codex_capabilities import CodexClientCapabilities
+from src.connectors.contracts import ConnectorRequestContext
+from src.connectors.openai_codex.contracts import (
+    CodexConnectorSettings,
+    CodexInputItem,
+    CodexPayload,
     CodexRequestContext,
     CodexToolSchema,
     CompatibilityResult,
@@ -684,23 +685,32 @@ class ICodexTransport(Protocol):
     Public boundary for streaming HTTP requests used by response executor.
     """
 
-    async def initiate_streaming_request(
-        self,
-        url: str,
-        payload: dict[str, Any],
-        headers: dict[str, str],
-        session_id: str,
-    ) -> StreamingResponseHandle:
-        """Initiate a streaming request to Codex API.
-
-        Args:
-            url: Codex API endpoint URL
-            payload: Request payload as dictionary
-            headers: HTTP headers including Authorization
-            session_id: Session identifier for logging and cancellation
-
-        Returns:
-            StreamingResponseHandle with iterator and cancel callback
+    async def initiate_streaming_request(
+        self,
+        url: str,
+        payload: dict[str, Any],
+        headers: dict[str, str],
+        session_id: str,
+        *,
+        context: ConnectorRequestContext | None = None,
+        backend: str = "openai-codex",
+        model: str = "unknown",
+        key_name: str | None = None,
+    ) -> StreamingResponseHandle:
+        """Initiate a streaming request to Codex API.
+
+        Args:
+            url: Codex API endpoint URL
+            payload: Request payload as dictionary
+            headers: HTTP headers including Authorization
+            session_id: Session identifier for logging and cancellation
+            context: Optional proxy request context for wire capture
+            backend: Backend key used for websocket capture metadata
+            model: Effective model name for websocket capture metadata
+            key_name: Optional capture key name override
+
+        Returns:
+            StreamingResponseHandle with iterator and cancel callback
 
         Raises:
             HTTPException: For 4xx/5xx responses