[Haik]: ckpt, pulled out shared mode resolution logic into its own helper class

backend/apps/agents/ResolvedModeConfig/ResolvedModeConfig.py

@@ -0,0 +1,48 @@
+from typing import Optional, Tuple, List
+
+from backend.apps.modes.modes import get_mode_by_id
+from backend.apps.modes.Mode import Mode
+from backend.apps.settings.settings import load_settings
+from backend.apps.agents.ResolvedModeConfig.compose_system_prompt import compose_system_prompt
+from backend.core.tools.shared_structs.Toolkit import Toolkit
+from typeguard import typechecked
+from pydantic import BaseModel, Field
+
+class ResolvedModeConfig(BaseModel):
+    system_prompt: Optional[str] = None
+    allowed_tools: List[str] = Field(default_factory=list)
+    disallowed_tools: List[str] = Field(default_factory=list)
+    cwd: Optional[str] = None
+
+    @typechecked
+    @classmethod
+    async def create(
+        cls,
+        mode_id: str,
+        session_prompt: Optional[str],
+        toolkit: Toolkit,
+    ) -> "ResolvedModeConfig":
+
+        settings = load_settings()
+        mode_def: Optional[Mode] = await get_mode_by_id(mode_id)
+
+        system_prompt: Optional[str] = compose_system_prompt(
+            global_default=settings.default_system_prompt,
+            mode_prompt=mode_def.system_prompt if mode_def else None,
+            session_prompt=session_prompt,
+        )
+
+        allowed_tools, disallowed_tools = toolkit.collect_tool_permissions()
+        if mode_def and mode_def.tools is not None:
+            mode_tool_set: set[str] = set[str](mode_def.tools)
+            disallowed_tools += [t for t in allowed_tools if t not in mode_tool_set]
+            allowed_tools = [t for t in allowed_tools if t in mode_tool_set]
+
+        cwd: Optional[str] = mode_def.default_folder if mode_def and mode_def.default_folder else None
+
+        return cls(
+            system_prompt=system_prompt,
+            allowed_tools=allowed_tools,
+            disallowed_tools=disallowed_tools,
+            cwd=cwd,
+        )

backend/apps/agents/ResolvedModeConfig/compose_system_prompt.py

@@ -0,0 +1,30 @@
+"""Pure prompt-building helpers.
+
+All functions are stateless — they accept data as parameters and return
+strings.  No imports from ``apps/`` or any external stores.
+"""
+
+from typing import Optional, List
+from typeguard import typechecked
+
+@typechecked
+def compose_system_prompt(
+    global_default: Optional[str] = None,
+    mode_prompt: Optional[str] = None,
+    session_prompt: Optional[str] = None,
+    connected_tools_ctx: Optional[str] = None,
+    browser_ctx: Optional[str] = None,
+) -> Optional[str]:
+    """Layer multiple prompt sources into one system prompt.
+
+    Order matters — earlier layers provide base context, later layers
+    override or augment.
+    """
+    parts: List[str] = [p for p in (
+        global_default,
+        mode_prompt,
+        session_prompt,
+        connected_tools_ctx,
+        browser_ctx,
+    ) if p]
+    return "\n\n".join(parts) if parts else None