From 704db1d66fe6281e008e34a8f6d3809ddba36713 Mon Sep 17 00:00:00 2001
From: Vidit Ostwal <110953813+Vidit-Ostwal@users.noreply.github.com>
Date: Thu, 27 Aug 2026 02:39:35 +0530
Subject: [PATCH] fix(llms): map default Claude Sonnet 4.6 to its 1M context
 window (#7125)

* fix(llms): map default Claude Sonnet 4.6 to its 1M context window

Native AnthropicCompletion fell back to 200k for claude-sonnet-4-6, so the default instance understated the documented limit.

* fix(llms): align Anthropic context windows with active Claude models

Retired Claude 3/2/Instant IDs no longer have dedicated entries; the map now covers the current Claude API lineup and their documented 1M vs 200k windows.

* fix(llms): map Claude Mythos 5 to its documented 1M context window

Native AnthropicCompletion fell back to 200k for claude-mythos-5 even though Anthropic lists a 1M-token window.
---
 .../llms/providers/anthropic/completion.py    | 21 +++++----
 .../tests/llms/anthropic/test_anthropic.py    | 45 +++++++++++++++++--
 2 files changed, 53 insertions(+), 13 deletions(-)

diff --git a/lib/crewai/src/crewai/llms/providers/anthropic/completion.py b/lib/crewai/src/crewai/llms/providers/anthropic/completion.py
index e2afec133..e6bc4255f 100644
--- a/lib/crewai/src/crewai/llms/providers/anthropic/completion.py
+++ b/lib/crewai/src/crewai/llms/providers/anthropic/completion.py
@@ -1953,16 +1953,19 @@ class AnthropicCompletion(BaseLLM):
         """Get the context window size for the model."""
         from crewai.llm import CONTEXT_WINDOW_USAGE_RATIO
 
+        # Current offered models. Unknown and retired IDs fall back to 200k.
         context_windows = {
-            "claude-3-5-sonnet": 200000,
-            "claude-3-5-haiku": 200000,
-            "claude-3-opus": 200000,
-            "claude-3-sonnet": 200000,
-            "claude-3-haiku": 200000,
-            "claude-3-7-sonnet": 200000,
-            "claude-2.1": 200000,
-            "claude-2": 100000,
-            "claude-instant": 100000,
+            "claude-fable-5": 1000000,
+            "claude-mythos-5": 1000000,
+            "claude-opus-5": 1000000,
+            "claude-sonnet-5": 1000000,
+            "claude-opus-4-8": 1000000,
+            "claude-opus-4-7": 1000000,
+            "claude-opus-4-6": 1000000,
+            "claude-sonnet-4-6": 1000000,
+            "claude-opus-4-5": 200000,
+            "claude-sonnet-4-5": 200000,
+            "claude-haiku-4-5": 200000,
         }
 
         for model_prefix, size in context_windows.items():
diff --git a/lib/crewai/tests/llms/anthropic/test_anthropic.py b/lib/crewai/tests/llms/anthropic/test_anthropic.py
index c26475010..f177a2bc4 100644
--- a/lib/crewai/tests/llms/anthropic/test_anthropic.py
+++ b/lib/crewai/tests/llms/anthropic/test_anthropic.py
@@ -4,7 +4,7 @@ import types
 from unittest.mock import AsyncMock, patch, MagicMock
 import pytest
 
-from crewai.llm import LLM
+from crewai.llm import CONTEXT_WINDOW_USAGE_RATIO, LLM
 from crewai.crew import Crew
 from crewai.agent import Agent
 from crewai.task import Task
@@ -116,6 +116,44 @@ def test_anthropic_completion_defaults_to_sonnet_4_6():
     assert llm.max_tokens == 128000
 
 
+def test_default_anthropic_completion_uses_sonnet_4_6_context_window():
+    from crewai.llms.providers.anthropic.completion import AnthropicCompletion
+
+    llm = AnthropicCompletion()
+    assert llm.get_context_window_size() == int(1_000_000 * CONTEXT_WINDOW_USAGE_RATIO)
+
+
+@pytest.mark.parametrize(
+    "model",
+    [
+        "claude-fable-5",
+        "claude-mythos-5",
+        "claude-opus-5",
+        "claude-sonnet-5",
+        "claude-opus-4-8",
+        "claude-opus-4-7",
+        "claude-opus-4-6",
+        "claude-sonnet-4-6",
+    ],
+)
+def test_current_1m_anthropic_models_use_1m_context_window(model: str) -> None:
+    from crewai.llms.providers.anthropic.completion import AnthropicCompletion
+
+    llm = AnthropicCompletion(model=model)
+    assert llm.get_context_window_size() == int(1_000_000 * CONTEXT_WINDOW_USAGE_RATIO)
+
+
+@pytest.mark.parametrize(
+    "model",
+    ["claude-opus-4-5", "claude-sonnet-4-5", "claude-haiku-4-5"],
+)
+def test_claude_4_5_family_uses_200k_context_window(model: str) -> None:
+    from crewai.llms.providers.anthropic.completion import AnthropicCompletion
+
+    llm = AnthropicCompletion(model=model)
+    assert llm.get_context_window_size() == int(200000 * CONTEXT_WINDOW_USAGE_RATIO)
+
+
 def test_anthropic_defaults_max_tokens_to_model_limit():
     """Native Anthropic used to default to 4096, which truncates large tool calls."""
     llm = LLM(model="anthropic/claude-unknown-future")
@@ -500,11 +538,10 @@ def test_anthropic_context_window_size():
     """
     Test that Anthropic models return correct context window sizes
     """
-    llm = LLM(model="anthropic/claude-3-5-sonnet-20241022")
+    llm = LLM(model="anthropic/claude-haiku-4-5")
     context_size = llm.get_context_window_size()
 
-    assert context_size > 100000
-    assert context_size <= 200000  # But not exceed the actual limit
+    assert context_size == int(200000 * CONTEXT_WINDOW_USAGE_RATIO)
 
 
 def test_anthropic_message_formatting():