fix(backend): add 429/5xx patterns to is_transient_api_error and add config validators

- Add rate-limit (429) and server error (5xx) string patterns to
  is_transient_api_error() so the fallback retry path catches these
  in addition to connection-level errors (ECONNRESET).
- Add ge/le validators on max_turns (1-500) and max_budget_usd
  (0.01-100.0) to prevent misconfiguration.
- Rename max_transient -> max_transient_retries and
  _can_retry_transient() -> _next_transient_backoff() for clarity.
- Add comprehensive tests for all new transient patterns and config
  boundary validation.

autogpt_platform/backend/backend/copilot/config.py

@@ -136,11 +136,15 @@ class ChatConfig(BaseSettings):
     )
     claude_agent_max_turns: int = Field(
         default=50,
+        ge=1,
+        le=500,
         description="Maximum number of agentic turns (tool-use loops) per query. "
         "Prevents runaway tool loops from burning budget.",
     )
     claude_agent_max_budget_usd: float = Field(
         default=5.0,
+        ge=0.01,
+        le=100.0,
         description="Maximum spend in USD per SDK query. The CLI aborts the "
         "request if this budget is exceeded.",
     )

autogpt_platform/backend/backend/copilot/constants.py

@@ -44,12 +44,32 @@ def parse_node_id_from_exec_id(node_exec_id: str) -> str:
 # Transient Anthropic API error detection
 # ---------------------------------------------------------------------------
 # Patterns in error text that indicate a transient Anthropic API error
-# (ECONNRESET / dropped TCP connection) which is retryable.
+# which is retryable.  Covers:
+#   - Connection-level: ECONNRESET, dropped TCP connections
+#   - HTTP 429: rate-limit / too-many-requests
+#   - HTTP 5xx: server errors, overloaded
 _TRANSIENT_ERROR_PATTERNS = (
+    # Connection-level
     "socket connection was closed unexpectedly",
     "ECONNRESET",
     "connection was forcibly closed",
     "network socket disconnected",
+    # 429 rate-limit patterns
+    "rate limit",
+    "rate_limit",
+    "too many requests",
+    "status code 429",
+    # 5xx server error patterns
+    "overloaded",
+    "internal server error",
+    "bad gateway",
+    "service unavailable",
+    "gateway timeout",
+    "status code 529",
+    "status code 500",
+    "status code 502",
+    "status code 503",
+    "status code 504",
 )
 
 FRIENDLY_TRANSIENT_MSG = "Anthropic connection interrupted — please retry"

autogpt_platform/backend/backend/copilot/sdk/p0_guardrails_test.py

@@ -2,7 +2,11 @@
 
 from unittest.mock import patch
 
+import pytest
+from pydantic import ValidationError
+
 from backend.copilot.config import ChatConfig
+from backend.copilot.constants import is_transient_api_error
 
 
 def _make_config(**overrides) -> ChatConfig:
@@ -258,3 +262,116 @@ class TestBuildSdkEnv:
             assert isinstance(env, dict)
             env["CLAUDE_CODE_TMPDIR"] = "/tmp/test"
             assert env["CLAUDE_CODE_TMPDIR"] == "/tmp/test"
+
+
+# ---------------------------------------------------------------------------
+# is_transient_api_error
+# ---------------------------------------------------------------------------
+
+
+class TestIsTransientApiError:
+    """Verify that is_transient_api_error detects all transient patterns."""
+
+    @pytest.mark.parametrize(
+        "error_text",
+        [
+            "socket connection was closed unexpectedly",
+            "ECONNRESET",
+            "connection was forcibly closed",
+            "network socket disconnected",
+        ],
+    )
+    def test_connection_level_errors(self, error_text: str):
+        assert is_transient_api_error(error_text)
+
+    @pytest.mark.parametrize(
+        "error_text",
+        [
+            "rate limit exceeded",
+            "rate_limit_error",
+            "Too Many Requests",
+            "status code 429",
+        ],
+    )
+    def test_429_rate_limit_errors(self, error_text: str):
+        assert is_transient_api_error(error_text)
+
+    @pytest.mark.parametrize(
+        "error_text",
+        [
+            "API is overloaded",
+            "Internal Server Error",
+            "Bad Gateway",
+            "Service Unavailable",
+            "Gateway Timeout",
+            "status code 529",
+            "status code 500",
+            "status code 502",
+            "status code 503",
+            "status code 504",
+        ],
+    )
+    def test_5xx_server_errors(self, error_text: str):
+        assert is_transient_api_error(error_text)
+
+    @pytest.mark.parametrize(
+        "error_text",
+        [
+            "invalid_api_key",
+            "Authentication failed",
+            "prompt is too long",
+            "model not found",
+            "",
+        ],
+    )
+    def test_non_transient_errors(self, error_text: str):
+        assert not is_transient_api_error(error_text)
+
+    def test_case_insensitive(self):
+        assert is_transient_api_error("SOCKET CONNECTION WAS CLOSED UNEXPECTEDLY")
+        assert is_transient_api_error("econnreset")
+
+
+# ---------------------------------------------------------------------------
+# Config validators for max_turns / max_budget_usd
+# ---------------------------------------------------------------------------
+
+
+class TestConfigValidators:
+    """Verify ge/le bounds on max_turns and max_budget_usd."""
+
+    def test_max_turns_rejects_zero(self):
+        with pytest.raises(ValidationError):
+            _make_config(claude_agent_max_turns=0)
+
+    def test_max_turns_rejects_negative(self):
+        with pytest.raises(ValidationError):
+            _make_config(claude_agent_max_turns=-1)
+
+    def test_max_turns_rejects_above_500(self):
+        with pytest.raises(ValidationError):
+            _make_config(claude_agent_max_turns=501)
+
+    def test_max_turns_accepts_boundary_values(self):
+        cfg_low = _make_config(claude_agent_max_turns=1)
+        assert cfg_low.claude_agent_max_turns == 1
+        cfg_high = _make_config(claude_agent_max_turns=500)
+        assert cfg_high.claude_agent_max_turns == 500
+
+    def test_max_budget_rejects_zero(self):
+        with pytest.raises(ValidationError):
+            _make_config(claude_agent_max_budget_usd=0.0)
+
+    def test_max_budget_rejects_negative(self):
+        with pytest.raises(ValidationError):
+            _make_config(claude_agent_max_budget_usd=-1.0)
+
+    def test_max_budget_rejects_above_100(self):
+        with pytest.raises(ValidationError):
+            _make_config(claude_agent_max_budget_usd=100.01)
+
+    def test_max_budget_accepts_boundary_values(self):
+        cfg_low = _make_config(claude_agent_max_budget_usd=0.01)
+        assert cfg_low.claude_agent_max_budget_usd == 0.01
+        cfg_high = _make_config(claude_agent_max_budget_usd=100.0)
+        assert cfg_high.claude_agent_max_budget_usd == 100.0

autogpt_platform/backend/backend/copilot/sdk/service.py

@@ -2027,20 +2027,20 @@ async def stream_chat_completion_sdk(
         # Transient retry helper — deduplicates the logic shared between
         # _HandledStreamError and the generic except-Exception handler.
         transient_retries = 0
-        max_transient = config.claude_agent_max_transient_retries
+        max_transient_retries = config.claude_agent_max_transient_retries
 
-        def _can_retry_transient() -> int | None:
-            """Check if a transient retry is possible.
+        def _next_transient_backoff() -> int | None:
+            """Return the next backoff delay in seconds, or ``None`` to surface the error.
 
             Returns the backoff seconds if a retry should be attempted,
-            or ``None`` if the error should be surfaced to the user.
-            Mutates outer ``transient_retries`` via nonlocal.
+            or ``None`` if retries are exhausted or events were already
+            yielded.  Mutates outer ``transient_retries`` via nonlocal.
             """
             nonlocal transient_retries
             if events_yielded > 0:
                 return None
             transient_retries += 1
-            if transient_retries > max_transient:
+            if transient_retries > max_transient_retries:
                 return None
             return 2 ** (transient_retries - 1)  # 1s, 2s, 4s, ...
 
@@ -2171,14 +2171,14 @@ async def stream_chat_completion_sdk(
                 if exc.code == "transient_api_error" or is_transient_api_error(
                     str(exc)
                 ):
-                    backoff = _can_retry_transient()
+                    backoff = _next_transient_backoff()
                     if backoff is not None:
                         logger.warning(
                             "%s Transient error — retrying in %ds (%d/%d)",
                             log_prefix,
                             backoff,
                             transient_retries,
-                            max_transient,
+                            max_transient_retries,
                         )
                         yield StreamStatus(
                             message=f"Connection interrupted, retrying in {backoff}s…"
@@ -2247,14 +2247,14 @@ async def stream_chat_completion_sdk(
                 # Transient API errors (ECONNRESET, 429, 5xx) — retry
                 # with exponential backoff via the shared helper.
                 if is_transient:
-                    backoff = _can_retry_transient()
+                    backoff = _next_transient_backoff()
                     if backoff is not None:
                         logger.warning(
                             "%s Transient exception — retrying in %ds (%d/%d)",
                             log_prefix,
                             backoff,
                             transient_retries,
-                            max_transient,
+                            max_transient_retries,
                         )
                         yield StreamStatus(
                             message=f"Connection interrupted, retrying "