Pathfinder MCP Server

"""Phase state machine for RPI workflow.""" from enum import Enum from typing import Self from pydantic import BaseModel class Phase(str, Enum): """Workflow phases.""" RESEARCH = "research" PLAN = "plan" IMPLEMENT = "implement" # Valid transitions: forward-only _VALID_TRANSITIONS: dict[Phase, set[Phase]] = { Phase.RESEARCH: {Phase.PLAN}, Phase.PLAN: {Phase.IMPLEMENT}, Phase.IMPLEMENT: set(), # Terminal phase } class PhaseState(BaseModel): """Tracks current phase and enforces transition guards.""" session_id: str current_phase: Phase = Phase.RESEARCH def can_transition_to(self, target: Phase) -> bool: """Check if transition to target phase is valid.""" return target in _VALID_TRANSITIONS.get(self.current_phase, set()) def transition_to(self, target: Phase) -> Self: """Transition to target phase. Raises ValueError if invalid.""" if not self.can_transition_to(target): raise ValueError( f"Invalid transition: {self.current_phase.value} -> {target.value}" ) return self.model_copy(update={"current_phase": target}) @property def is_research(self) -> bool: return self.current_phase == Phase.RESEARCH @property def is_plan(self) -> bool: return self.current_phase == Phase.PLAN @property def is_implement(self) -> bool: return self.current_phase == Phase.IMPLEMENT