refactor(agents,core,frontends): typed kinds, prompts per kind, frontend agents as parameters

src/beaver_gateway/frontends/api/frontend.py

@@ -22,7 +22,8 @@ from sqlalchemy import select as sa_select
 from sqlmodel import col
 
 from beaver_gateway.core import audit
-from beaver_gateway.core.conversations import KINDS, SEEDS
+from beaver_gateway.core.conversations import SEEDS
+from beaver_gateway.core.kinds import Kind, as_kind
 from beaver_gateway.frontends._auth import require_token
 from beaver_gateway.frontends._sse import (
     KEEPALIVE,
@@ -34,7 +35,7 @@ from beaver_gateway.frontends.base import Frontend
 from beaver_gateway.storage.models import Usage
 
 if TYPE_CHECKING:
-    from collections.abc import AsyncIterator, Mapping
+    from collections.abc import AsyncIterator
 
     from beaver_gateway.core.conversations import Conversations
     from beaver_gateway.frontends.base import GatewayRuntime
@@ -57,16 +58,27 @@ class ApiFrontend(Frontend):
         host: str = "0.0.0.0",  # noqa: S104
         port: int = 8004,
         public_base_url: str | None = None,
-        default_agents: Mapping[str, str] | None = None,
+        master_agent: str | None = None,
+        branch_agent: str | None = None,
+        deep_agent: str | None = None,
+        job_agent: str | None = None,
     ) -> None:
         self.host = host
         self.port = port
         self.public_base_url = public_base_url.rstrip("/") if public_base_url else None
-        self.default_agents = dict(default_agents or {})
+        self.master_agent = master_agent
+        self.branch_agent = branch_agent
+        self.deep_agent = deep_agent
+        self.job_agent = job_agent
         self._app: FastAPI | None = None
 
-    def agent_for(self, kind: str) -> str | None:
-        return self.default_agents.get(kind)
+    def agent_for(self, kind: Kind) -> str | None:
+        return {
+            "master": self.master_agent,
+            "branch": self.branch_agent,
+            "deep": self.deep_agent,
+            "job": self.job_agent,
+        }.get(kind)
 
     def configure(self, runtime: GatewayRuntime) -> None:
         if runtime.conversations is None or runtime.bus is None:
@@ -175,12 +187,13 @@ def _build_app(runtime: GatewayRuntime) -> FastAPI:  # noqa: PLR0915
     async def create_conversation(request: Request) -> dict[str, Any]:
         token = await require_token(request, runtime, scope=SCOPE)
         data = await body_of(request)
-        kind = str(data.get("kind") or "deep")
         agent = data.get("agent")
-        if kind not in KINDS or kind == "fork":
-            raise HTTPException(
-                status.HTTP_400_BAD_REQUEST, f"kind must be one of {KINDS[:-1]}"
-            )
+        try:
+            kind = as_kind(str(data.get("kind") or "deep"))
+        except ValueError as exc:
+            raise HTTPException(status.HTTP_400_BAD_REQUEST, str(exc)) from exc
+        if kind == "fork":
+            raise HTTPException(status.HTTP_400_BAD_REQUEST, "fork is internal")
         if agent is not None and (
             not isinstance(agent, str) or agent not in runtime.agents
         ):

src/beaver_gateway/frontends/base.py

@@ -19,6 +19,7 @@ if TYPE_CHECKING:
 
     from beaver_gateway.backends.base import Backend
     from beaver_gateway.core.auth import TokenStore
+    from beaver_gateway.core.kinds import Kind
     from beaver_gateway.core.registry import AgentRegistry, McpRegistry
     from beaver_gateway.core.turn_record import TurnRecord
     from beaver_gateway.storage import Database
@@ -101,7 +102,7 @@ class Frontend(ABC):
     """
 
     name: str = ""
-    kinds: tuple[str, ...] = ()
+    kinds: tuple[Kind, ...] = ()
 
     @abstractmethod
     def configure(self, runtime: GatewayRuntime) -> None: ...
@@ -109,7 +110,7 @@ class Frontend(ABC):
     @abstractmethod
     async def serve(self) -> None: ...
 
-    def agent_for(self, kind: str) -> str | None:  # noqa: ARG002
+    def agent_for(self, kind: Kind) -> str | None:  # noqa: ARG002
         return None
 
     async def materialize(self, conv: Conversation) -> ConversationBinding | None:  # noqa: ARG002

src/beaver_gateway/frontends/markdown/frontend.py

@@ -76,6 +76,7 @@ from beaver_gateway.frontends.markdown.mirror import FRONTEND, ChatMirror
 if TYPE_CHECKING:
     from collections.abc import AsyncIterator, Callable
 
+    from beaver_gateway.core.kinds import Kind
     from beaver_gateway.frontends.base import GatewayRuntime
     from beaver_gateway.storage.models import Conversation, ConversationBinding
 
@@ -173,7 +174,7 @@ class MarkdownFrontend(Frontend):
             raise RuntimeError(msg)
         return self._mirror
 
-    def agent_for(self, kind: str) -> str | None:
+    def agent_for(self, kind: Kind) -> str | None:
         return self.default_agent if kind == "deep" else None
 
     async def materialize(self, conv: Conversation) -> ConversationBinding | None: