refactor(supervisor): separate MCP dispatch from transport

bot_bottle/gateway/supervisor/mcp_dispatch.py

@@ -0,0 +1,79 @@
+"""Framework-neutral MCP method and tool dispatch."""
+
+from __future__ import annotations
+
+import json
+from dataclasses import dataclass
+from typing import Callable, Protocol
+
+from bot_bottle.gateway.egress.context import resolve_client_context
+from bot_bottle.gateway.egress.schema import route_to_yaml_dict
+from bot_bottle.gateway.policy_resolver import PolicyResolver
+from bot_bottle.supervisor import types as _sv
+
+
+class Request(Protocol):
+    @property
+    def method(self) -> str: ...
+
+    @property
+    def params(self) -> dict[str, object]: ...
+
+
+class MethodNotFoundError(Exception):
+    """Raised when a JSON-RPC method has no MCP handler."""
+
+
+Handler = Callable[[dict[str, object]], object]
+
+
+@dataclass(frozen=True)
+class Handlers:
+    initialize: Handler
+    tools_list: Handler
+    list_routes: Handler
+    check_proposal: Handler
+    propose: Handler
+
+
+def dispatch(request: Request, handlers: Handlers) -> object:
+    """Route one parsed request without depending on the HTTP server."""
+    if request.method == "initialize":
+        return handlers.initialize(request.params)
+    if request.method == "notifications/initialized":
+        return None
+    if request.method == "tools/list":
+        return handlers.tools_list(request.params)
+    if request.method != "tools/call":
+        raise MethodNotFoundError(request.method)
+
+    tool = request.params.get("name")
+    if tool == _sv.TOOL_LIST_EGRESS_ROUTES:
+        return handlers.list_routes(request.params)
+    if tool == _sv.TOOL_CHECK_PROPOSAL:
+        return handlers.check_proposal(request.params)
+    return handlers.propose(request.params)
+
+
+def resolved_routes_payload(
+    resolver: PolicyResolver,
+    source_ip: str,
+    identity_token: str,
+) -> dict[str, object]:
+    """Render the calling bottle's routes, failing closed to an empty list."""
+    config, _slug, _tokens = resolve_client_context(
+        resolver, source_ip, identity_token,
+    )
+    body = json.dumps(
+        {"routes": [route_to_yaml_dict(route) for route in config.routes]},
+        indent=2,
+    )
+    return {"content": [{"type": "text", "text": body}], "isError": False}
+
+
+__all__ = [
+    "Handlers",
+    "MethodNotFoundError",
+    "dispatch",
+    "resolved_routes_payload",
+]