From 29abaeb98fcc48c0a9f3d87c105c13151351475e Mon Sep 17 00:00:00 2001
From: kshitijk4poor <82637225+kshitijk4poor@users.noreply.github.com>
Date: Mon, 27 Jul 2026 22:45:24 +0500
Subject: [PATCH 1/2] fix(timeouts): add claude-fable to reasoning
 stale-timeout floor table
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claude-fable-5 is a Mythos-class reasoning model (1M context, 128K output,
adaptive thinking per anthropic_adapter.py) but was missing from the
_REASONING_STALE_TIMEOUT_FLOORS table. Without a floor entry it got the
default 180s stale timeout (300s with context scaling), which is too short
for fable-5's thinking phase on large contexts.

Each stale kill bumped the cross-turn circuit breaker streak; after 5
consecutive kills _check_stale_giveup() fired immediately (elapsed: 0.00s),
aborting all calls with "Provider has been unresponsive for 5 consecutive
stale attempts." Users with 191K-token contexts hit this reliably.

Add ("claude-fable", 600) — deep-reasoning tier alongside o1/deepseek-r1/
nemotron-3-ultra. The claude-fable slug matches claude-fable-5 and future
variants via the existing right-anchor regex.
---
 agent/reasoning_timeouts.py                       | 10 ++++++++++
 tests/agent/test_reasoning_stale_timeout_floor.py |  4 ++++
 2 files changed, 14 insertions(+)

diff --git a/agent/reasoning_timeouts.py b/agent/reasoning_timeouts.py
index 8af5ab799f48..9c5fc2020152 100644
--- a/agent/reasoning_timeouts.py
+++ b/agent/reasoning_timeouts.py
@@ -106,6 +106,14 @@ _REASONING_STALE_TIMEOUT_FLOORS: tuple[tuple[str, int], ...] = (
     ("claude-sonnet-5", 180),
     ("claude-sonnet-4.5", 180),
     ("claude-sonnet-4.6", 180),
+    # Anthropic Mythos-class named reasoning models (claude-fable-5, …).
+    # 1M context + 128K output — heavier thinking phase than the
+    # numbered Claude line, so the floor is in the deep-reasoning tier
+    # alongside o1 / deepseek-r1 / nemotron-3-ultra.  Without this
+    # entry the stale-stream detector kills fable-5's thinking phase
+    # at the default 180s (300s with context scaling), tripping the
+    # cross-turn circuit breaker after 5 consecutive stale kills.
+    ("claude-fable", 600),
     # xAI Grok reasoning variants.  Explicit reasoning-only keys
     # plus one for the ``non-reasoning`` variant so users picking
     # the fast variant don't get the 300s floor.  Bare ``grok-3``,
@@ -207,6 +215,8 @@ def get_reasoning_stale_timeout_floor(model: object) -> Optional[float]:
     300.0
     >>> get_reasoning_stale_timeout_floor("anthropic/claude-opus-4-6")
     240.0
+    >>> get_reasoning_stale_timeout_floor("anthropic/claude-fable-5")
+    600.0
     >>> get_reasoning_stale_timeout_floor("gpt-4o") is None
     True
     >>> get_reasoning_stale_timeout_floor("olmo-1") is None
diff --git a/tests/agent/test_reasoning_stale_timeout_floor.py b/tests/agent/test_reasoning_stale_timeout_floor.py
index ec05cb54dd60..608c83d10408 100644
--- a/tests/agent/test_reasoning_stale_timeout_floor.py
+++ b/tests/agent/test_reasoning_stale_timeout_floor.py
@@ -74,6 +74,10 @@ import pytest
     ("anthropic/claude-opus-4-20250514", 240.0),
     ("anthropic/claude-sonnet-4.5", 180.0),
     ("anthropic/claude-sonnet-4.6", 180.0),
+    # Anthropic Mythos-class named reasoning models — deep-reasoning tier.
+    ("anthropic/claude-fable-5", 600.0),
+    ("claude-fable-5", 600.0),
+    ("claude-fable", 600.0),
     # xAI Grok reasoning variants — explicit, not bare `grok`.
     ("x-ai/grok-4-fast-reasoning", 300.0),
     ("x-ai/grok-4.20-reasoning", 300.0),

From f5f5ac312af29ea1bc276663e2b7d71091753276 Mon Sep 17 00:00:00 2001
From: kshitijk4poor <82637225+kshitijk4poor@users.noreply.github.com>
Date: Mon, 27 Jul 2026 23:10:30 +0500
Subject: [PATCH 2/2] chore: add contributor mapping for reinbeumer@gmail.com

Needed for PR #72677 attribution check.
---
 contributors/emails/reinbeumer@gmail.com | 1 +
 1 file changed, 1 insertion(+)
 create mode 100644 contributors/emails/reinbeumer@gmail.com

diff --git a/contributors/emails/reinbeumer@gmail.com b/contributors/emails/reinbeumer@gmail.com
new file mode 100644
index 000000000000..26c0b64b9500
--- /dev/null
+++ b/contributors/emails/reinbeumer@gmail.com
@@ -0,0 +1 @@
+reinbeumer