diff --git a/.env.example b/.env.example
index 1f3acae..2c020db 100644
--- a/.env.example
+++ b/.env.example
@@ -44,7 +44,7 @@ WORKDIR=/var/lib/gitea-codex/worktrees
 MAX_DIFF_BYTES=200000
 MAX_REVIEW_MINUTES=10
 CONCURRENCY=1
-JOB_LEASE_TIMEOUT_SECONDS=300
+JOB_LEASE_TIMEOUT_SECONDS=660
 STUCK_JOB_RECOVERY_ACTION=requeue
 MAX_STUCK_JOB_RETRIES=1
 
diff --git a/src/gitea_codex_bot/config.py b/src/gitea_codex_bot/config.py
index 9e2a19f..c010ac9 100644
--- a/src/gitea_codex_bot/config.py
+++ b/src/gitea_codex_bot/config.py
@@ -3,7 +3,7 @@ from __future__ import annotations
 from functools import lru_cache
 from typing import Literal
 
-from pydantic import Field, SecretStr, field_validator
+from pydantic import Field, SecretStr, field_validator, model_validator
 from pydantic_settings import BaseSettings, SettingsConfigDict
 
 
@@ -38,7 +38,7 @@ class Settings(BaseSettings):
     max_diff_bytes: int = Field(default=200000, alias="MAX_DIFF_BYTES")
     max_review_minutes: int = Field(default=10, alias="MAX_REVIEW_MINUTES")
     concurrency: int = Field(default=1, alias="CONCURRENCY")
-    job_lease_timeout_seconds: int = Field(default=300, alias="JOB_LEASE_TIMEOUT_SECONDS")
+    job_lease_timeout_seconds: int = Field(default=660, alias="JOB_LEASE_TIMEOUT_SECONDS")
     stuck_job_recovery_action: Literal["requeue", "fail"] = Field(default="requeue", alias="STUCK_JOB_RECOVERY_ACTION")
     max_stuck_job_retries: int = Field(default=1, alias="MAX_STUCK_JOB_RETRIES")
 
@@ -63,6 +63,16 @@ class Settings(BaseSettings):
         values = [item.strip() for item in self.allowed_repos.split(",")]
         return {value for value in values if value}
 
+    @model_validator(mode="after")
+    def validate_job_lease_timeout(self) -> "Settings":
+        minimum_lease_timeout = (self.max_review_minutes * 60) + 60
+        if self.job_lease_timeout_seconds < minimum_lease_timeout:
+            raise ValueError(
+                "JOB_LEASE_TIMEOUT_SECONDS must be at least MAX_REVIEW_MINUTES*60 + 60 "
+                f"(minimum {minimum_lease_timeout}s for MAX_REVIEW_MINUTES={self.max_review_minutes})."
+            )
+        return self
+
 
 @lru_cache(maxsize=1)
 def get_settings() -> Settings:
diff --git a/tests/test_config.py b/tests/test_config.py
index e1a5a6b..3b3a903 100644
--- a/tests/test_config.py
+++ b/tests/test_config.py
@@ -1,3 +1,6 @@
+import pytest
+from pydantic import ValidationError
+
 from gitea_codex_bot.config import get_settings
 
 
@@ -11,3 +14,12 @@ def test_codex_auth_defaults_to_api_key_mode() -> None:
     settings = get_settings()
     assert settings.codex_auth_mode == "api_key"
     assert settings.codex_auth_json_path is None
+
+
+def test_job_lease_timeout_must_cover_max_review_runtime(monkeypatch: pytest.MonkeyPatch) -> None:
+    monkeypatch.setenv("MAX_REVIEW_MINUTES", "10")
+    monkeypatch.setenv("JOB_LEASE_TIMEOUT_SECONDS", "300")
+    get_settings.cache_clear()
+
+    with pytest.raises(ValidationError, match="JOB_LEASE_TIMEOUT_SECONDS must be at least"):
+        get_settings()