diff --git a/README.md b/README.md
index 1a75b292c3..db05092ad3 100644
--- a/README.md
+++ b/README.md
@@ -506,6 +506,8 @@ DeerFlow still uses `Forwarded` / `X-Forwarded-*` headers to recover the browser
 
 > Cancelling a model recovery probe, including while it is queued or waiting to retry, lets the next call check whether the provider has recovered. Cancellation does not count as a provider failure or release another call's active recovery probe.
 >
+> Model retries honor valid provider `Retry-After` hints up to 24 hours, including waits longer than the local backoff cap. Malformed, non-finite, or over-limit hints use normal backoff instead. This applies to numeric/date hints in LLM error handling and integer-second hints in Claude's retry path.
+>
 > With lease heartbeat enabled, a transient RunStore renewal error is retried only until the last confirmed lease expires; the stale worker then cancels local execution and suppresses checkpoint, completion-hook, delivery-receipt, and thread-status finalization. A remote tool side effect already in flight may still be outside local cancellation.
 >
 > Reconciliation uses an atomic takeover claim that re-checks the lease after candidate selection, so a successful owner renewal wins over orphan recovery and only one reconciler can report a run as recovered. When multiple Gateway workers share the Docker/AIO or E2B sandbox backend, also configure `sandbox.ownership.type: redis`; E2B uses the leases during background startup and periodic reconciliation so duplicate/orphan cleanup cannot terminate a live peer's sandbox.
diff --git a/backend/packages/harness/deerflow/agents/middlewares/AGENTS.md b/backend/packages/harness/deerflow/agents/middlewares/AGENTS.md
index 08d710ddd6..8422f399b6 100644
--- a/backend/packages/harness/deerflow/agents/middlewares/AGENTS.md
+++ b/backend/packages/harness/deerflow/agents/middlewares/AGENTS.md
@@ -74,7 +74,7 @@ No match: skip inspection, log ID. Tests: `test_read_mark_tool_call_correlation.
    their narrower discovery allowlists never rebuild the shared thread view or
    force eager sandbox acquisition.
 8. **DanglingToolCallMiddleware** - Injects placeholder ToolMessages for AIMessage tool_calls that lack responses (e.g., user interruption), preserving raw provider tool-call payloads in `additional_kwargs["tool_calls"]`; malformed tool-call names and arguments are sanitized in the model-bound request so strict OpenAI-compatible providers do not reject the next request
-9. **LLMErrorHandlingMiddleware** - Converts provider/model failures to recoverable assistant errors. Sync and async calls carry circuit-generation ownership; only the current owner may settle or release a half-open probe, so stale completions cannot affect a newer recovery attempt. Cancellation propagates unchanged without retry or failure accounting.
+9. **LLMErrorHandlingMiddleware** - Converts provider/model failures to recoverable assistant errors. Numeric/date retry hints share the 24-hour ceiling in `utils.retry_after`; unusable hints use jitter. Sync and async calls carry circuit-generation ownership; only the current owner may settle or release a half-open probe, so stale completions cannot affect a newer recovery attempt. Cancellation propagates unchanged without retry or failure accounting.
 10. **ArtifactResolutionMiddleware** - See [tool artifacts](TOOL_ARTIFACTS.md).
 11. **Authorization / GuardrailMiddleware** - Up to two independent pre-tool-call gates run here. When `authorization.enabled`, the `AuthorizationProvider` instance already used for Layer 1 capability filtering is wrapped by `GuardrailAuthorizationAdapter` and reused for Layer 2 execution checks. A generated `tool_search` bypasses the adapter's second provider call only when the current build has a concrete deferred setup; its catalog was already filtered by Layer 1, and an ordinary same-named tool without that deferred setup receives no exemption. When `guardrails.enabled`, the explicitly configured `GuardrailProvider` is appended after authorization and still evaluates every call, including `tool_search`. Authorization therefore runs outermost and can deny before an external guardrail call; both use the existing middleware's fail-closed, audit, sync/async, and error-`ToolMessage` behavior. See the authorization RFC and [docs/GUARDRAILS.md](../../../../../docs/GUARDRAILS.md).
 
diff --git a/backend/packages/harness/deerflow/agents/middlewares/llm_error_handling_middleware.py b/backend/packages/harness/deerflow/agents/middlewares/llm_error_handling_middleware.py
index 401957b7e8..559c6406c9 100644
--- a/backend/packages/harness/deerflow/agents/middlewares/llm_error_handling_middleware.py
+++ b/backend/packages/harness/deerflow/agents/middlewares/llm_error_handling_middleware.py
@@ -27,6 +27,7 @@ from deerflow.agents.middlewares.model_response import append_visible_text, fini
 from deerflow.config.app_config import AppConfig
 from deerflow.models.request_admission import AdmissionError
 from deerflow.utils.custom_events import aemit_custom_event, emit_custom_event
+from deerflow.utils.retry_after import bounded_retry_after_ms
 
 logger = logging.getLogger(__name__)
 
@@ -695,7 +696,7 @@ class LLMErrorHandlingMiddleware(AgentMiddleware[AgentState]):
     def _build_retry_delay_ms(self, prev_delay_ms: int | None, exc: BaseException, reason: str = "transient") -> int:
         """Compute the next retry delay (ms) using decorrelated jitter.
 
-        An explicit ``Retry-After`` from the provider is honored as-is (no
+        A finite ``Retry-After`` up to 24 hours is honored as-is (no
         jitter) - the server told us exactly when to come back, and for a
         burst-rate 429 this is strongly preferred over any computed delay.
         Otherwise AWS-style "decorrelated jitter" is applied:
@@ -1074,12 +1075,12 @@ def _extract_retry_after_ms(exc: BaseException) -> int | None:
 
     try:
         multiplier = 1 if "ms" in header_name.lower() else 1000
-        return max(0, int(float(raw) * multiplier))
-    except (TypeError, ValueError):
+        return bounded_retry_after_ms(float(raw) * multiplier)
+    except (TypeError, ValueError, OverflowError):
         try:
             target = parsedate_to_datetime(str(raw))
             delta = target.timestamp() - time.time()
-            return max(0, int(delta * 1000))
+            return bounded_retry_after_ms(delta * 1000)
         except (TypeError, ValueError, OverflowError):
             return None
 
diff --git a/backend/packages/harness/deerflow/models/AGENTS.md b/backend/packages/harness/deerflow/models/AGENTS.md
index bc2e54b29c..c5b751fc06 100644
--- a/backend/packages/harness/deerflow/models/AGENTS.md
+++ b/backend/packages/harness/deerflow/models/AGENTS.md
@@ -129,6 +129,13 @@ Offline HTTP-stream coverage: `tests/test_codex_stream_terminal_events.py`.
 - `ClaudeChatModel.model_post_init` calls `load_claude_code_credential()` for every instance, and `create_chat_model` builds fresh instances per run (lead agent, title, summarization, subagents)
 - `$CLAUDE_CODE_OAUTH_TOKEN_FILE_DESCRIPTOR` is a one-shot handoff: a pipe returns EOF and a file keeps its advanced offset. `_read_secret_from_file_descriptor` therefore caches a non-empty secret per `(env_var, fd)` under a lock held across the read. Do not drop the cache or the lock — later instances would get no credential, and the Anthropic SDK raises `TypeError: Could not resolve authentication method` before sending. Empty reads, `OSError`, and UTF-8 decode failures are not cached; unreadable handoffs return `None` so the loader can try credential files. Warnings must not include token contents. The key is the descriptor number on purpose — a closed handoff keeps serving its token, and a secret placed on a recycled number in-process is not re-read unless the cache is cleared. The cache is per process, so a new process (e.g. a uvicorn `--reload` worker) cannot recover a drained descriptor. Pinned by `tests/test_credential_loader.py` and `tests/test_claude_fd_encoding.py`, including two-instance `ClaudeChatModel` tests
 
+### Claude Retry Delays (`claude_provider.py`)
+
+`_calc_backoff_ms` uses `utils.retry_after.bounded_retry_after_ms` for integer-second
+provider hints. Invalid or over-24-hour values retain local exponential backoff;
+finite negative values clamp to zero. Sync/async 429/500 regressions live in
+`tests/test_claude_provider_retry_after.py` and use offline provider doubles.
+
 ### Claude Prompt Caching (`packages/harness/deerflow/models/claude_provider.py`)
 
 - The request payload shares objects with the caller: langchain-anthropic forwards Claude-native blocks (an image or document with a `source`, search results) and list-form system blocks by reference, and a reused tool binding passes its own tool dicts (the lead agent re-binds per call, so its tool dicts are fresh). Writing `cache_control` in place checkpointed the markers with the thread's messages, and the stale ones pushed every later request past the 4-breakpoint limit
diff --git a/backend/packages/harness/deerflow/models/claude_provider.py b/backend/packages/harness/deerflow/models/claude_provider.py
index dffaa33b92..68239eb24f 100644
--- a/backend/packages/harness/deerflow/models/claude_provider.py
+++ b/backend/packages/harness/deerflow/models/claude_provider.py
@@ -30,6 +30,8 @@ from langchain_anthropic import ChatAnthropic
 from langchain_core.messages import BaseMessage
 from pydantic import PrivateAttr
 
+from deerflow.utils.retry_after import bounded_retry_after_ms
+
 logger = logging.getLogger(__name__)
 
 MAX_RETRIES = 3
@@ -427,8 +429,10 @@ class ClaudeChatModel(ChatAnthropic):
             retry_after = error.response.headers.get("Retry-After")
             if retry_after:
                 try:
-                    total_ms = int(retry_after) * 1000
-                except (ValueError, TypeError):
+                    hint_ms = bounded_retry_after_ms(int(retry_after) * 1000)
+                    if hint_ms is not None:
+                        total_ms = hint_ms
+                except (ValueError, TypeError, OverflowError):
                     pass
 
         return total_ms
diff --git a/backend/packages/harness/deerflow/utils/AGENTS.md b/backend/packages/harness/deerflow/utils/AGENTS.md
index 0d67eda661..e2cc85c86f 100644
--- a/backend/packages/harness/deerflow/utils/AGENTS.md
+++ b/backend/packages/harness/deerflow/utils/AGENTS.md
@@ -1,3 +1,10 @@
+### Model Retry Hints
+
+`retry_after.py::bounded_retry_after_ms` shares the 24-hour provider-hint ceiling
+between LLM middleware (numeric/date hints) and Claude backoff. Non-finite or
+over-limit delays return `None` for local backoff; finite negatives clamp to zero.
+Validate before integer truncation and preserve valid hints above the jitter cap.
+
 ### Port Allocation Bounds
 
 `network.py::PortAllocator.allocate` caps its exclusive search endpoint at
diff --git a/backend/packages/harness/deerflow/utils/retry_after.py b/backend/packages/harness/deerflow/utils/retry_after.py
new file mode 100644
index 0000000000..7a56796f77
--- /dev/null
+++ b/backend/packages/harness/deerflow/utils/retry_after.py
@@ -0,0 +1,14 @@
+"""Bounds for provider-supplied model retry delays."""
+
+import math
+
+MAX_RETRY_AFTER_MS = 24 * 60 * 60 * 1000
+
+
+def bounded_retry_after_ms(delay_ms: int | float) -> int | None:
+    """Return a finite delay up to 24 hours, or None to use local backoff."""
+    if isinstance(delay_ms, float) and not math.isfinite(delay_ms):
+        return None
+    if delay_ms > MAX_RETRY_AFTER_MS:
+        return None
+    return max(0, int(delay_ms))
diff --git a/backend/tests/test_claude_provider_retry_after.py b/backend/tests/test_claude_provider_retry_after.py
new file mode 100644
index 0000000000..a497024470
--- /dev/null
+++ b/backend/tests/test_claude_provider_retry_after.py
@@ -0,0 +1,74 @@
+"""Offline regressions for provider-owned Retry-After backoff."""
+
+import asyncio
+import time
+from types import SimpleNamespace
+
+import anthropic
+import httpx
+import pytest
+from langchain_anthropic import ChatAnthropic
+from langchain_core.messages import AIMessage, HumanMessage
+from langchain_core.outputs import ChatGeneration, ChatResult
+
+from deerflow.models.claude_provider import ClaudeChatModel
+
+
+@pytest.mark.parametrize("attempt", [1, 2])
+@pytest.mark.parametrize("raw", ["1e999", "inf", "-inf", "nan", "1e15", "999999999999999999999999999999", pytest.param("9" * 1000, id="huge-integer"), "86401", "bad", None])
+def test_unusable_claude_retry_after_uses_default_backoff(attempt: int, raw: str | None) -> None:
+    error = Exception("rate limited")
+    error.response = SimpleNamespace(headers={"Retry-After": raw})
+    assert ClaudeChatModel._calc_backoff_ms(attempt, error) == 2400 * 2 ** (attempt - 1)
+
+
+@pytest.mark.parametrize(("raw", "expected_ms"), [("-2", 0), ("0", 0), ("60", 60000), ("86400", 86400000)])
+def test_usable_claude_retry_after_is_preserved(raw: str, expected_ms: int) -> None:
+    error = Exception("rate limited")
+    error.response = SimpleNamespace(headers={"Retry-After": raw})
+    assert ClaudeChatModel._calc_backoff_ms(1, error) == expected_ms
+
+
+@pytest.mark.anyio
+@pytest.mark.parametrize("mode", ["sync", "async"])
+@pytest.mark.parametrize("error_type", [anthropic.RateLimitError, anthropic.InternalServerError])
+@pytest.mark.parametrize("raw", ["999999999999999999999999999999", "86401", "1e999", "60"])
+async def test_claude_retry_loops_use_safe_delay(monkeypatch: pytest.MonkeyPatch, mode: str, error_type: type[anthropic.APIStatusError], raw: str) -> None:
+    # Avoid credential discovery/client construction; only the provider call is fake.
+    monkeypatch.setattr(ClaudeChatModel, "model_post_init", lambda self, context: None)
+    model = ClaudeChatModel(model="claude-sonnet-4-6", anthropic_api_key="sk-ant-fake", retry_max_attempts=2)
+    model._is_oauth = False
+    response = httpx.Response(429 if error_type is anthropic.RateLimitError else 500, headers={"Retry-After": raw}, request=httpx.Request("POST", "https://example.invalid/messages"))
+    error = error_type("provider failure", response=response, body={})
+    expected = ChatResult(generations=[ChatGeneration(message=AIMessage(content="recovered"))])
+    attempts = 0
+    waits: list[float] = []
+
+    def provider_call(self, messages, **kwargs) -> ChatResult:
+        nonlocal attempts
+        attempts += 1
+        if attempts == 1:
+            raise error
+        return expected
+
+    async def async_provider_call(self, messages, **kwargs) -> ChatResult:
+        return provider_call(self, messages, **kwargs)
+
+    def fake_sleep(delay: float) -> None:
+        assert delay == (60 if raw == "60" else 2.4)
+        waits.append(delay)
+
+    async def fake_async_sleep(delay: float) -> None:
+        fake_sleep(delay)
+
+    monkeypatch.setattr(ChatAnthropic, "_generate", provider_call)
+    monkeypatch.setattr(ChatAnthropic, "_agenerate", async_provider_call)
+    monkeypatch.setattr(time, "sleep", fake_sleep)
+    monkeypatch.setattr(asyncio, "sleep", fake_async_sleep)
+    if mode == "sync":
+        result = model._generate([HumanMessage(content="hi")])
+    else:
+        result = await model._agenerate([HumanMessage(content="hi")])
+    assert result is expected
+    assert attempts == 2
+    assert len(waits) == 1
diff --git a/backend/tests/test_llm_error_handling_middleware.py b/backend/tests/test_llm_error_handling_middleware.py
index 5c0e3178f9..d54f27d442 100644
--- a/backend/tests/test_llm_error_handling_middleware.py
+++ b/backend/tests/test_llm_error_handling_middleware.py
@@ -5,6 +5,8 @@ import concurrent.futures
 import threading
 import time
 from collections.abc import Iterator
+from datetime import UTC, datetime, timedelta
+from email.utils import format_datetime
 from types import SimpleNamespace
 from typing import Any
 
@@ -20,6 +22,7 @@ from langgraph.errors import GraphBubbleUp
 from deerflow.agents.middlewares.llm_error_handling_middleware import (
     EmptyModelResponseError,
     LLMErrorHandlingMiddleware,
+    _extract_retry_after_ms,
 )
 from deerflow.config.app_config import AppConfig, LlmCallConfig
 from deerflow.config.sandbox_config import SandboxConfig
@@ -1871,6 +1874,97 @@ def test_retry_delay_honors_retry_after_without_jitter() -> None:
     assert delay == 5000
 
 
+@pytest.mark.parametrize("header_name", ["Retry-After", "retry-after", "Retry-After-Ms", "retry-after-ms"])
+@pytest.mark.parametrize("header_value", ["1e999", "inf", "-inf", "nan", "1e15", "1e308", "99999999999999999999", "not-a-number"])
+def test_unusable_retry_after_falls_back_to_jitter(header_name: str, header_value: str) -> None:
+    """Unusable provider delays must fall back to bounded jitter."""
+    middleware = _build_middleware(retry_base_delay_ms=100, retry_cap_delay_ms=10000)
+    exc = FakeError("rate limited", status_code=429, headers={header_name: header_value})
+    assert 100 <= middleware._build_retry_delay_ms(100, exc) <= 300
+
+
+@pytest.mark.parametrize("header_name", ["Retry-After", "retry-after", "Retry-After-Ms", "retry-after-ms"])
+@pytest.mark.parametrize("header_value", ["1e999", "inf", "-inf", "nan", "1e15", "1e308", "99999999999999999999", "not-a-number"])
+def test_extract_unusable_retry_after_ms_returns_none(header_name: str, header_value: str) -> None:
+    """Mirror the delay-level cases, including nan's existing safe fallback."""
+    exc = FakeError("rate limited", status_code=429, headers={header_name: header_value})
+    assert _extract_retry_after_ms(exc) is None
+
+
+@pytest.mark.parametrize(
+    ("header_name", "header_value", "expected_ms"),
+    [
+        ("Retry-After", "60", 60000),
+        ("retry-after-ms", "60000", 60000),
+        ("Retry-After", "2.5", 2500),
+        ("retry-after-ms", "2.5", 2),
+        ("Retry-After", "-2", 0),
+        ("retry-after-ms", "-2", 0),
+        ("Retry-After", "0", 0),
+        ("retry-after-ms", "0", 0),
+        ("Retry-After", "86400", 86400000),
+        ("retry-after-ms", "86400000", 86400000),
+        ("Retry-After", "86400.001", None),
+        ("retry-after-ms", "86400001", None),
+    ],
+)
+def test_retry_after_numeric_boundaries(header_name: str, header_value: str, expected_ms: int | None) -> None:
+    exc = FakeError("rate limited", status_code=429, headers={header_name: header_value})
+    assert _extract_retry_after_ms(exc) == expected_ms
+    middleware = _build_middleware(retry_base_delay_ms=100, retry_cap_delay_ms=10000)
+    delay = middleware._build_retry_delay_ms(100, exc)
+    if expected_ms is None:
+        assert 100 <= delay <= 300
+    else:
+        assert delay == expected_ms
+
+
+@pytest.mark.parametrize(("delta_seconds", "expected_ms"), [(-60, 0), (60, 60000), (86400, 86400000), (86401, None)])
+def test_retry_after_date_boundaries(monkeypatch: pytest.MonkeyPatch, delta_seconds: int, expected_ms: int | None) -> None:
+    now = datetime(2026, 1, 1, tzinfo=UTC)
+    monkeypatch.setattr(time, "time", lambda: now.timestamp())
+    raw = format_datetime(now + timedelta(seconds=delta_seconds), usegmt=True)
+    exc = FakeError("rate limited", status_code=429, headers={"Retry-After": raw})
+    assert _extract_retry_after_ms(exc) == expected_ms
+
+
+@pytest.mark.anyio
+@pytest.mark.parametrize("mode", ["sync", "async"])
+@pytest.mark.parametrize("header_name", ["Retry-After", "retry-after-ms"])
+@pytest.mark.parametrize("header_value", ["1e999", "nan", "1e15", "99999999999999999999", "Fri, 31 Dec 9999 23:59:59 GMT"])
+async def test_retry_loops_recover_from_unusable_hints(monkeypatch: pytest.MonkeyPatch, mode: str, header_name: str, header_value: str) -> None:
+    middleware = _build_middleware(retry_max_attempts=2, retry_base_delay_ms=100, retry_cap_delay_ms=300)
+    attempts = 0
+    waits: list[float] = []
+
+    def fake_sleep(delay: float) -> None:
+        assert 0.1 <= delay <= 0.3
+        waits.append(delay)
+
+    async def fake_async_sleep(delay: float) -> None:
+        fake_sleep(delay)
+
+    def handler(_request) -> AIMessage:
+        nonlocal attempts
+        attempts += 1
+        if attempts == 1:
+            raise FakeError("rate limited", status_code=429, headers={header_name: header_value})
+        return AIMessage(content="recovered")
+
+    async def async_handler(request) -> AIMessage:
+        return handler(request)
+
+    monkeypatch.setattr(time, "sleep", fake_sleep)
+    monkeypatch.setattr(asyncio, "sleep", fake_async_sleep)
+    if mode == "sync":
+        result = middleware.wrap_model_call(SimpleNamespace(), handler)
+    else:
+        result = await middleware.awrap_model_call(SimpleNamespace(), async_handler)
+    assert result.content == "recovered"
+    assert attempts == 2
+    assert len(waits) == 1
+
+
 @pytest.mark.anyio
 async def test_async_retry_loop_emits_jittered_delays_within_bounds(
     monkeypatch: pytest.MonkeyPatch,