diff --git a/backend/apps/agents/core/error_classify.py b/backend/apps/agents/core/error_classify.py
index d3ad8074..3a5d4aea 100644
--- a/backend/apps/agents/core/error_classify.py
+++ b/backend/apps/agents/core/error_classify.py
@@ -12,10 +12,30 @@ _TRANSIENT_CAPACITY_PATTERNS = re.compile(
     r"|internal\s+server\s+error"
     r"|rate[_\s-]?limit(?:_error)?"
     r"|ECONNRESET|ETIMEDOUT|ENETUNREACH|fetch\s+failed"
+    r"|resource[_\s-]?exhausted"
     r"|upstream\s+connect\s+error)",
     re.IGNORECASE,
 )
 
+# A first message ships the full tool schema; 9Router rewrites Anthropic
+# tools[].input_schema into Gemini function_declarations / OpenAI params, and a
+# construct it can't translate makes the provider 400 (INVALID_ARGUMENT) with
+# zero tokens. That is NOT auth, reconnecting won't help, the request shape is
+# wrong, so we classify it apart and stop the catch-all from showing a
+# "reconnect your subscription" card for a tool-schema 400.
+_TRANSLATION_ERROR_PATTERNS = re.compile(
+    r"(?:function_declarations"
+    r"|invalid_argument"
+    r"|invalid\s+json\s+payload"
+    r"|unknown\s+name\b"
+    r"|cannot\s+find\s+field"
+    r"|proto\s+field"
+    r"|input_schema"
+    r"|\btools\[\d+\]"
+    r")",
+    re.IGNORECASE,
+)
+
 # Patterns that look rate-limit-ish but are actually non-transient (user quota,
 # auth, context-window tier gate). Must NOT retry, upgrading, reauthing, or
 # trimming context is required. The long-context-required variant is what
@@ -69,6 +89,17 @@ def _is_free_trial_exhausted(exc: BaseException, extra_text: str = "") -> bool:
     ))
 
 
+def _is_translation_error(exc: BaseException, extra_text: str = "") -> bool:
+    """True when the upstream 400 is a tool-schema / protocol translation
+    failure (9Router rewriting Anthropic tools into Gemini function_declarations
+    or OpenAI params), not auth or capacity. Kept distinct so the catch-all
+    stops mislabeling a schema 400 as an expired-subscription reconnect card."""
+    combined = f"{exc!s}\n{extra_text}".strip()
+    if not combined:
+        return False
+    return bool(_TRANSLATION_ERROR_PATTERNS.search(combined))
+
+
 def _is_auth_error(exc: BaseException, extra_text: str = "") -> bool:
     """True when the upstream error is a 401/403 auth failure.
 
@@ -80,6 +111,10 @@ def _is_auth_error(exc: BaseException, extra_text: str = "") -> bool:
     combined = f"{exc!s}\n{extra_text}".strip()
     if not combined:
         return False
+    # A tool-schema translation 400 can carry provider/connection wording that
+    # trips the auth regex below; it isn't auth, so don't claim it is.
+    if _is_translation_error(exc, extra_text):
+        return False
     return bool(re.search(
         r"\b(401|403)\b"
         r"|invalid\s+authentication\s+credentials"
diff --git a/backend/tests/test_v2_invariants.py b/backend/tests/test_v2_invariants.py
index 6b7f0bf3..51d146ed 100644
--- a/backend/tests/test_v2_invariants.py
+++ b/backend/tests/test_v2_invariants.py
@@ -523,6 +523,33 @@ def test_resolve_sdk_gemini_prefers_antigravity_over_api_key():
         assert registry.resolve_model_id_for_sdk("gemini-3-flash", s2) == "gc/gemini-3-flash-preview"
 
 
+def test_error_classify_schema_translation_400_is_not_auth():
+    """A 9Router tool-schema translation 400 can carry provider/connection
+    wording that trips the auth regex, so it used to surface a misleading
+    'reconnect your subscription' card for what is really a schema bug. The
+    translation guard must win: schema 400 -> not auth; a real auth failure
+    with no translation signature still reads as auth."""
+    from backend.apps.agents.core.error_classify import _is_auth_error, _is_translation_error
+    both = Exception("provider not connected: 400 INVALID_ARGUMENT at "
+                     "tools[0].function_declarations[0].parameters")
+    assert _is_translation_error(both)
+    assert not _is_auth_error(both), "schema-400 must not be classified as auth"
+    # Pure auth failures (no translation signature) still classify as auth.
+    assert _is_auth_error(Exception("provider not connected: gemini"))
+    assert _is_auth_error(Exception("401 invalid authentication credentials"))
+    assert not _is_translation_error(Exception("401 invalid authentication credentials"))
+
+
+def test_error_classify_gemini_resource_exhausted_is_transient():
+    """gemini-cli's free-tier 429 surfaces as RESOURCE_EXHAUSTED; it must count
+    as transient so the existing backoff/retry catches it instead of dying as a
+    hard first-message error. A 403 (hard auth/quota) must still NOT retry."""
+    from backend.apps.agents.core.error_classify import _is_transient_capacity_error
+    assert _is_transient_capacity_error(Exception("429 RESOURCE_EXHAUSTED: Quota exceeded"))
+    assert _is_transient_capacity_error(Exception("RESOURCE_EXHAUSTED"))
+    assert not _is_transient_capacity_error(Exception("403 permission denied"))
+
+
 def test_banned_models_not_offered():
     """Claude Fable (banned) and Gemini 3.1 Pro (no working lane: AG can't serve
     it, AI Studio key 429s pro-preview) were pulled from the picker. Guard so a