diff --git a/scripts/ci/strix_quick_gate.sh b/scripts/ci/strix_quick_gate.sh
index 66be927b56..b7fb59bfe4 100755
--- a/scripts/ci/strix_quick_gate.sh
+++ b/scripts/ci/strix_quick_gate.sh
@@ -2651,6 +2651,20 @@ run_strix_once() {
 	if ! resolved_target_path="$(resolve_current_target_path "$TARGET_PATH")"; then
 		return 1
 	fi
+	# contextual-orchestrator's gateway deliberately rejects any request that
+	# combines stream_options.include_usage=true with tools (a correctness
+	# guarantee against silently-incomplete usage accounting; out of scope to
+	# change here). Strix's agent loop always streams and always sends tools,
+	# so every call through that gateway hits the rejection immediately.
+	# Strix itself ships an opt-in for exactly this: LLM_DISABLE_STREAMING=true
+	# makes each turn a single non-streaming get_response (stream:false on the
+	# wire, so stream_options is never sent) replayed as one terminal stream
+	# event; nothing else about the run loop changes. Scope it narrowly to the
+	# contextual-orchestrator loopback so other providers keep real streaming.
+	local strix_disable_streaming="false"
+	if is_contextual_orchestrator_api_base "$llm_api_base_value"; then
+		strix_disable_streaming="true"
+	fi
 	local start_epoch
 	start_epoch="$(date +%s)"
 	local child_llm_api_key=""
@@ -2682,6 +2696,7 @@ run_strix_once() {
 	STRIX_CHILD_EXECUTABLE_ROOT="$STRIX_EXECUTABLE_ROOT" \
 	STRIX_CHILD_EXECUTABLE_SHA256="$STRIX_EXECUTABLE_SHA256" \
 	STRIX_CHILD_REQUIRE_EXECUTABLE_INTEGRITY="${IS_PR_EVIDENCE_RUN:-false}" \
+	STRIX_CHILD_DISABLE_STREAMING="$strix_disable_streaming" \
 python3 - "$timeout_seconds" "$resolved_target_path" "$SCAN_MODE" "$STRIX_LOG" "$STRIX_SCAN_WORKING_DIR" <<'PY'
 import hashlib
 import hmac
@@ -2736,6 +2751,12 @@ child_env["LLM_MODEL"] = os.environ["STRIX_CHILD_MODEL"]
 if os.environ.get("STRIX_CHILD_LLM_API_KEY"):
     child_env["LLM_API_KEY"] = os.environ["STRIX_CHILD_LLM_API_KEY"]
 child_env["STRIX_REPORTS_DIR"] = os.environ["STRIX_CHILD_REPORTS_DIR"]
+if os.environ.get("STRIX_CHILD_DISABLE_STREAMING", "").strip().lower() == "true":
+    # See the comment above strix_disable_streaming's assignment in bash:
+    # this routes only the contextual-orchestrator gateway through Strix's
+    # own non-streaming fallback so stream_options is never sent alongside
+    # tools, without touching how Strix talks to any other provider.
+    child_env["LLM_DISABLE_STREAMING"] = "true"
 for key, value in os.environ.items():
     if key.startswith("FAKE_STRIX_") and value:
         child_env[key] = value
diff --git a/scripts/ci/test_strix_quick_gate.sh b/scripts/ci/test_strix_quick_gate.sh
index b528e8bafc..afd2546e8c 100644
--- a/scripts/ci/test_strix_quick_gate.sh
+++ b/scripts/ci/test_strix_quick_gate.sh
@@ -327,6 +327,9 @@ assert_strix_workflow_pr_trigger_hardened() {
 	assert_file_contains "$GATE_SCRIPT" 'child_env["PNPM_CONFIG_IGNORE_SCRIPTS"] = "true"' "strix gate child process disables pnpm lifecycle scripts"
 	assert_file_contains "$GATE_SCRIPT" 'child_env["YARN_ENABLE_SCRIPTS"] = "false"' "strix gate child process disables yarn lifecycle scripts"
 	assert_file_contains "$GATE_SCRIPT" 'child_env["PYTHONWARNINGS"] = "ignore:Pydantic serializer warnings:UserWarning:pydantic.main"' "strix gate child env narrowly filters the known third-party Pydantic serializer warning"
+	assert_file_contains "$GATE_SCRIPT" 'if is_contextual_orchestrator_api_base "$llm_api_base_value"; then' "strix gate scopes the non-streaming opt-in to the contextual-orchestrator loopback gateway"
+	assert_file_contains "$GATE_SCRIPT" 'STRIX_CHILD_DISABLE_STREAMING="$strix_disable_streaming"' "strix gate threads the streaming opt-in through to the child process environment"
+	assert_file_contains "$GATE_SCRIPT" 'child_env["LLM_DISABLE_STREAMING"] = "true"' "strix gate disables Strix's own SDK streaming for the contextual-orchestrator gateway, which rejects stream_options.include_usage alongside tools"
 	assert_file_contains "$GATE_SCRIPT" '[[ "$normalized_changed_file" =~ ^backend/.+\.py$ ]]' "strix gate detects nested backend Python files for PR-scoped import context"
 	assert_file_contains "$GATE_SCRIPT" '[[ "$normalized_changed_file" == scripts/ci/test_*.sh || "$normalized_changed_file" == scripts/ci/*_test.sh ]]' "strix gate excludes large CI test harness scripts from model scan input"
 	assert_file_contains "$GATE_SCRIPT" "Materialized PR-head changed-file scope for Strix scan" "strix gate avoids copying the full PR head tree into privileged scan targets by default"
@@ -3289,7 +3292,7 @@ set -euo pipefail
 printf '%s\n' "${STRIX_LLM:-}" >> "${FAKE_STRIX_CALL_LOG:?}"
 printf '%s\n' "${LLM_API_BASE:-<unset>}" >> "${FAKE_STRIX_API_BASE_LOG:?}"
 if [ -n "${FAKE_STRIX_RUNTIME_ENV_LOG:-}" ]; then
-	printf 'LLM_TIMEOUT=%s;STRIX_MEMORY_COMPRESSOR_TIMEOUT=%s;STRIX_REASONING_EFFORT=%s;STRIX_LLM_MAX_RETRIES=%s;GEMINI_LOCATION=%s;PYTHONWARNINGS=%s;NPM_CONFIG_IGNORE_SCRIPTS=%s;PNPM_CONFIG_IGNORE_SCRIPTS=%s;YARN_ENABLE_SCRIPTS=%s;UNRELATED_SECRET=%s\n' \
+	printf 'LLM_TIMEOUT=%s;STRIX_MEMORY_COMPRESSOR_TIMEOUT=%s;STRIX_REASONING_EFFORT=%s;STRIX_LLM_MAX_RETRIES=%s;GEMINI_LOCATION=%s;PYTHONWARNINGS=%s;NPM_CONFIG_IGNORE_SCRIPTS=%s;PNPM_CONFIG_IGNORE_SCRIPTS=%s;YARN_ENABLE_SCRIPTS=%s;UNRELATED_SECRET=%s;LLM_DISABLE_STREAMING=%s\n' \
 		"${LLM_TIMEOUT:-<unset>}" \
 		"${STRIX_MEMORY_COMPRESSOR_TIMEOUT:-<unset>}" \
 		"${STRIX_REASONING_EFFORT:-<unset>}" \
@@ -3299,7 +3302,8 @@ if [ -n "${FAKE_STRIX_RUNTIME_ENV_LOG:-}" ]; then
 		"${NPM_CONFIG_IGNORE_SCRIPTS:-<unset>}" \
 		"${PNPM_CONFIG_IGNORE_SCRIPTS:-<unset>}" \
 		"${YARN_ENABLE_SCRIPTS:-<unset>}" \
-		"${UNRELATED_SECRET:-<unset>}" >> "${FAKE_STRIX_RUNTIME_ENV_LOG:?}"
+		"${UNRELATED_SECRET:-<unset>}" \
+		"${LLM_DISABLE_STREAMING:-<unset>}" >> "${FAKE_STRIX_RUNTIME_ENV_LOG:?}"
 fi
 
 target_path=""
@@ -5929,6 +5933,13 @@ PY
 			"$runtime_env_log" \
 			"LLM_TIMEOUT=90;STRIX_MEMORY_COMPRESSOR_TIMEOUT=10;STRIX_REASONING_EFFORT=minimal;STRIX_LLM_MAX_RETRIES=1;GEMINI_LOCATION=GLOBAL;PYTHONWARNINGS=ignore:Pydantic serializer warnings:UserWarning:pydantic.main;NPM_CONFIG_IGNORE_SCRIPTS=true;PNPM_CONFIG_IGNORE_SCRIPTS=true;YARN_ENABLE_SCRIPTS=false;UNRELATED_SECRET=<unset>" \
 			"scenario=$scenario runtime env forwarding"
+		# Non-contextual-orchestrator providers (gemini here) never see the
+		# stream-disabling opt-in: it is scoped narrowly to the gateway that
+		# rejects stream_options.include_usage alongside tools.
+		assert_file_contains \
+			"$runtime_env_log" \
+			"LLM_DISABLE_STREAMING=<unset>" \
+			"scenario=$scenario non-gateway providers keep real streaming"
 	fi
 	if [ "$scenario" = "custom-openai-compatible-preserves-effort" ]; then
 		assert_file_contains \
@@ -5936,6 +5947,16 @@ PY
 			"STRIX_REASONING_EFFORT=minimal" \
 			"scenario=$scenario custom compatible endpoint effort"
 	fi
+	if [ "$scenario" = "contextual-orchestrator-gateway-model-qualification" ]; then
+		# contextual-orchestrator rejects stream_options.include_usage=true
+		# alongside tools; Strix's agent loop always sends both, so the gate
+		# routes this gateway through Strix's own LLM_DISABLE_STREAMING opt-in
+		# (single non-streaming get_response per turn) instead of streaming.
+		assert_file_contains \
+			"$runtime_env_log" \
+			"LLM_DISABLE_STREAMING=true" \
+			"scenario=$scenario contextual-orchestrator gateway disables SDK streaming to avoid the stream_options+tools rejection"
+	fi
 
 	if [ "$scenario" = "report-known-internal-warning-sanitized" ]; then
 		assert_file_not_contains \