Coverage for little_loops / context_window.py: 25%

1"""Single source of truth for model → context-window size mapping. 

2 

3Precedence (highest to lowest): 

41. Explicit ``override`` argument (non-zero) 

52. ``LL_CONTEXT_LIMIT`` environment variable (non-zero integer) 

63. ``[1m]`` suffix on model id → 1_000_000 

74. Exact model-id lookup in MODEL_CONTEXT_WINDOW 

85. 200_000 conservative floor 

9 

10# keep in sync with hooks/scripts/context-monitor.sh:get_context_limit() 

11""" 

12 

13from __future__ import annotations 

14 

15import os 

16 

17# Known model context windows in tokens. 

18# Models not listed here fall back to the 200_000 floor. 

19MODEL_CONTEXT_WINDOW: dict[str, int] = { 

20 # Claude 4.x — 200k base context 

21 "claude-opus-4-8": 200_000, 

22 "claude-opus-4-7": 200_000, 

23 "claude-opus-4-6": 200_000, 

24 "claude-opus-4-5": 200_000, 

25 "claude-sonnet-4-6": 200_000, 

26 "claude-sonnet-4-5": 200_000, 

27 "claude-haiku-4-5": 200_000, 

28 "claude-haiku-4-5-20251001": 200_000, 

29 # Claude 3.x (legacy) 

30 "claude-opus-3-7": 200_000, 

31 "claude-sonnet-3-7": 200_000, 

32 "claude-haiku-3-5": 200_000, 

33} 

34 

35_DEFAULT_CONTEXT_WINDOW = 200_000 

36_1M_CONTEXT_WINDOW = 1_000_000 

37 

38 

39def context_window_for(model: str | None, override: int | None = None) -> int: 

40 """Resolve context-window size for a model id. 

41 

42 Args: 

43 model: Model identifier string (e.g. ``"claude-opus-4-8[1m]"``), 

44 or ``None`` to use env-var / floor. 

45 override: Explicit token count; takes top precedence when non-zero. 

46 

47 Returns: 

48 Context window size in tokens (always a positive int). 

49 """ 

50 # 1. Explicit override argument 

51 if override: 

52 return int(override) 

53 

54 # 2. LL_CONTEXT_LIMIT environment variable 

55 env_val = os.environ.get("LL_CONTEXT_LIMIT", "") 

56 if env_val: 

57 try: 

58 parsed = int(env_val) 

59 if parsed > 0: 

60 return parsed 

61 except ValueError: 

62 pass 

63 

64 if model is None: 

65 return _DEFAULT_CONTEXT_WINDOW 

66 

67 # 3. [1m] suffix → 1M context 

68 if model.endswith("[1m]"): 

69 return _1M_CONTEXT_WINDOW 

70 

71 # 4. Exact model-id lookup 

72 window = MODEL_CONTEXT_WINDOW.get(model) 

73 if window is not None: 

74 return window 

75 

76 # 5. Conservative floor 

77 return _DEFAULT_CONTEXT_WINDOW