Initial commit: add .gitignore and README

fusionagi/core/scheduler.py

@@ -0,0 +1,89 @@
+"""Scheduler: think vs act, tool selection, retry logic, fallback modes for AGI."""
+
+from enum import Enum
+from typing import Any, Callable
+
+from fusionagi._logger import logger
+
+
+class SchedulerMode(str, Enum):
+    """Whether to think (reason) or act (tool) next."""
+
+    THINK = "think"
+    ACT = "act"
+
+
+class FallbackMode(str, Enum):
+    """Fallback when primary path fails."""
+
+    RETRY = "retry"
+    SIMPLIFY_PLAN = "simplify_plan"
+    HUMAN_HANDOFF = "human_handoff"
+    ABORT = "abort"
+
+
+class Scheduler:
+    """
+    Decides think vs act, tool selection policy, retry/backoff, fallback.
+    Callers (e.g. Supervisor) query next_action() and record outcomes.
+    """
+
+    def __init__(
+        self,
+        default_mode: SchedulerMode = SchedulerMode.ACT,
+        max_retries_per_step: int = 2,
+        fallback_sequence: list[FallbackMode] | None = None,
+    ) -> None:
+        self._default_mode = default_mode
+        self._max_retries = max_retries_per_step
+        self._fallback_sequence = fallback_sequence or [
+            FallbackMode.RETRY,
+            FallbackMode.SIMPLIFY_PLAN,
+            FallbackMode.HUMAN_HANDOFF,
+            FallbackMode.ABORT,
+        ]
+        self._retry_counts: dict[str, int] = {}  # step_key -> count
+        self._fallback_index: dict[str, int] = {}  # task_id -> index into fallback_sequence
+
+    def next_mode(
+        self,
+        task_id: str,
+        step_id: str,
+        context: dict[str, Any] | None = None,
+    ) -> SchedulerMode:
+        """
+        Return whether to think (reason more) or act (execute step).
+        Override via context["force_think"] or context["force_act"].
+        """
+        if context:
+            if context.get("force_think"):
+                return SchedulerMode.THINK
+            if context.get("force_act"):
+                return SchedulerMode.ACT
+        return self._default_mode
+
+    def should_retry(self, task_id: str, step_id: str) -> bool:
+        """Return True if step should be retried (under max_retries)."""
+        key = f"{task_id}:{step_id}"
+        count = self._retry_counts.get(key, 0)
+        return count < self._max_retries
+
+    def record_retry(self, task_id: str, step_id: str) -> None:
+        """Increment retry count for step."""
+        key = f"{task_id}:{step_id}"
+        self._retry_counts[key] = self._retry_counts.get(key, 0) + 1
+        logger.debug("Scheduler recorded retry", extra={"task_id": task_id, "step_id": step_id})
+
+    def next_fallback(self, task_id: str) -> FallbackMode | None:
+        """Return next fallback mode for task, or None if exhausted."""
+        idx = self._fallback_index.get(task_id, 0)
+        if idx >= len(self._fallback_sequence):
+            return None
+        mode = self._fallback_sequence[idx]
+        self._fallback_index[task_id] = idx + 1
+        logger.info("Scheduler fallback", extra={"task_id": task_id, "fallback": mode.value})
+        return mode
+
+    def reset_fallback(self, task_id: str) -> None:
+        """Reset fallback index for task (e.g. after success)."""
+        self._fallback_index.pop(task_id, None)