diff --git a/src/agents/embedded-agent-runner/run/runtime-context-prompt.test.ts b/src/agents/embedded-agent-runner/run/runtime-context-prompt.test.ts
index b80509f9839a..93340e8b10c0 100644
--- a/src/agents/embedded-agent-runner/run/runtime-context-prompt.test.ts
+++ b/src/agents/embedded-agent-runner/run/runtime-context-prompt.test.ts
@@ -5,7 +5,6 @@ import {
   buildCurrentInboundPrompt,
   buildCurrentInboundPromptContextPrefix,
   buildRuntimeContextCustomMessage,
-  buildRuntimeContextSystemContext,
   resolveRuntimeContextPromptParts,
 } from "./runtime-context-prompt.js";
 
@@ -352,20 +351,14 @@ describe("runtime context prompt submission", () => {
     });
   });
 
-  it("labels next-turn runtime context only when used as prompt-local system context", () => {
-    const systemContext = buildRuntimeContextSystemContext("secret runtime context");
+  it("labels runtime-only events as system context", () => {
+    const parts = resolveRuntimeContextPromptParts({
+      effectivePrompt: "internal event",
+      transcriptPrompt: "",
+    });
 
-    expect(systemContext).toContain(
-      "OpenClaw runtime context for the immediately preceding user message.",
-    );
-    expect(systemContext).toContain("not user-authored");
-    expect(systemContext).toContain("secret runtime context");
-  });
-
-  it("labels runtime-only events as system context", async () => {
-    const { buildRuntimeEventSystemContext } = await import("./runtime-context-prompt.js");
-
-    expect(buildRuntimeEventSystemContext("internal event")).toContain("OpenClaw runtime event.");
-    expect(buildRuntimeEventSystemContext("internal event")).toContain("not user-authored");
+    expect(parts.runtimeSystemContext).toContain("OpenClaw runtime event.");
+    expect(parts.runtimeSystemContext).toContain("not user-authored");
+    expect(parts.runtimeSystemContext).toContain("internal event");
   });
 });
diff --git a/src/agents/embedded-agent-runner/run/runtime-context-prompt.ts b/src/agents/embedded-agent-runner/run/runtime-context-prompt.ts
index e534f388d243..a7d239a69be8 100644
--- a/src/agents/embedded-agent-runner/run/runtime-context-prompt.ts
+++ b/src/agents/embedded-agent-runner/run/runtime-context-prompt.ts
@@ -133,7 +133,10 @@ export function resolveRuntimeContextPromptParts(params: {
             : {}),
           runtimeContext,
           runtimeOnly: true,
-          runtimeSystemContext: buildRuntimeEventSystemContext(runtimeContext),
+          runtimeSystemContext: buildRuntimeContextMessageContent({
+            runtimeContext,
+            kind: "runtime-event",
+          }),
         }
       : {
           prompt: "",
@@ -169,16 +172,6 @@ function buildRuntimeContextMessageContent(params: {
   ].join("\n");
 }
 
-/** Builds the hidden next-turn system context payload for model conversion. */
-export function buildRuntimeContextSystemContext(runtimeContext: string): string {
-  return buildRuntimeContextMessageContent({ runtimeContext, kind: "next-turn" });
-}
-
-/** Builds the hidden runtime-event system context payload for empty runtime-only turns. */
-export function buildRuntimeEventSystemContext(runtimeContext: string): string {
-  return buildRuntimeContextMessageContent({ runtimeContext, kind: "runtime-event" });
-}
-
 /** Creates a non-displayed custom transcript message for runtime context, if any exists. */
 export function buildRuntimeContextCustomMessage(
   runtimeContext: string | undefined,
@@ -190,7 +183,10 @@ export function buildRuntimeContextCustomMessage(
   return {
     role: "custom",
     customType: OPENCLAW_RUNTIME_CONTEXT_CUSTOM_TYPE,
-    content: buildRuntimeContextSystemContext(trimmedRuntimeContext),
+    content: buildRuntimeContextMessageContent({
+      runtimeContext: trimmedRuntimeContext,
+      kind: "next-turn",
+    }),
     display: false,
     details: { source: "openclaw-runtime-context" },
     timestamp: Date.now(),