diff --git a/src/infra/outbound/message-action-runner.core-send.test.ts b/src/infra/outbound/message-action-runner.core-send.test.ts
index 677c1e474eea..df9d6d7fa73e 100644
--- a/src/infra/outbound/message-action-runner.core-send.test.ts
+++ b/src/infra/outbound/message-action-runner.core-send.test.ts
@@ -343,6 +343,146 @@ describe("runMessageAction core send routing", () => {
     expect(sendText).toHaveBeenCalledOnce();
   });
 
+  it("prepends messages.responsePrefix to message-tool sends", async () => {
+    const sendText = registerSlackTextPlugin();
+
+    await runMessageAction({
+      cfg: {
+        channels: { slack: { enabled: true } },
+        messages: { responsePrefix: "[Nexus]" },
+      } as OpenClawConfig,
+      action: "send",
+      params: {
+        channel: "slack",
+        target: "channel:OTHER",
+        message: "hello world",
+      },
+      dryRun: false,
+    });
+
+    expect(sendText).toHaveBeenCalledOnce();
+    expect(firstMockArg(sendText, "send text").text).toBe("[Nexus] hello world");
+  });
+
+  it("does not double-apply responsePrefix when the text already carries it", async () => {
+    const sendText = registerSlackTextPlugin();
+
+    await runMessageAction({
+      cfg: {
+        channels: { slack: { enabled: true } },
+        messages: { responsePrefix: "[Nexus]" },
+      } as OpenClawConfig,
+      action: "send",
+      params: {
+        channel: "slack",
+        target: "channel:OTHER",
+        message: "[Nexus] already prefixed",
+      },
+      dryRun: false,
+    });
+
+    expect(sendText).toHaveBeenCalledOnce();
+    expect(firstMockArg(sendText, "send text").text).toBe("[Nexus] already prefixed");
+  });
+
+  it("leaves media-only sends without a responsePrefix", async () => {
+    const sendMedia = vi.fn().mockResolvedValue({
+      channel: "slack",
+      messageId: "m1",
+      chatId: "C123",
+    });
+    setActivePluginRegistry(
+      createTestRegistry([
+        {
+          pluginId: "slack",
+          source: "test",
+          plugin: {
+            ...createOutboundTestPlugin({
+              id: "slack",
+              outbound: {
+                deliveryMode: "direct",
+                sendText: vi.fn().mockResolvedValue({
+                  channel: "slack",
+                  messageId: "t1",
+                  chatId: "C123",
+                }),
+                sendMedia,
+              },
+            }),
+            config: {
+              listAccountIds: () => ["default"],
+              resolveAccount: () => ({ enabled: true }),
+              isConfigured: () => true,
+            },
+          },
+        },
+      ]),
+    );
+
+    await runMessageAction({
+      cfg: {
+        channels: { slack: { enabled: true } },
+        messages: { responsePrefix: "[Nexus]" },
+      } as OpenClawConfig,
+      action: "send",
+      params: {
+        channel: "slack",
+        target: "channel:OTHER",
+        media: "https://example.com/cat.png",
+      },
+      dryRun: false,
+    });
+
+    expect(sendMedia).toHaveBeenCalledOnce();
+    expect(firstMockArg(sendMedia, "send media").text ?? "").toBe("");
+  });
+
+  it("resolves identity templates in responsePrefix on message-tool sends", async () => {
+    const sendText = registerSlackTextPlugin();
+
+    await runMessageAction({
+      cfg: {
+        channels: { slack: { enabled: true } },
+        messages: { responsePrefix: "[{identity.name}]" },
+        agents: { list: [{ id: "main", identity: { name: "Nexus" } }] },
+      } as OpenClawConfig,
+      action: "send",
+      params: {
+        channel: "slack",
+        target: "channel:OTHER",
+        message: "hello world",
+      },
+      agentId: "main",
+      dryRun: false,
+    });
+
+    expect(sendText).toHaveBeenCalledOnce();
+    expect(firstMockArg(sendText, "send text").text).toBe("[Nexus] hello world");
+  });
+
+  it("skips responsePrefix on tool sends when a model template cannot be resolved", async () => {
+    const sendText = registerSlackTextPlugin();
+
+    await runMessageAction({
+      cfg: {
+        channels: { slack: { enabled: true } },
+        messages: { responsePrefix: "[{provider}/{model}]" },
+      } as OpenClawConfig,
+      action: "send",
+      params: {
+        channel: "slack",
+        target: "channel:OTHER",
+        message: "hello world",
+      },
+      dryRun: false,
+    });
+
+    expect(sendText).toHaveBeenCalledOnce();
+    // A tool send performs no live model selection, so the unresolved template is dropped
+    // rather than leaked as a literal `{provider}/{model}` prefix.
+    expect(firstMockArg(sendText, "send text").text).toBe("hello world");
+  });
+
   it("uses best-effort delivery for explicit current-source message-tool-only replies", async () => {
     const sendText = registerSlackTextPlugin();
 
diff --git a/src/infra/outbound/message-action-runner.ts b/src/infra/outbound/message-action-runner.ts
index 6517c508aa09..468a641a997b 100644
--- a/src/infra/outbound/message-action-runner.ts
+++ b/src/infra/outbound/message-action-runner.ts
@@ -7,6 +7,7 @@ import {
 import { resolveSendableOutboundReplyParts } from "openclaw/plugin-sdk/reply-payload";
 import { stripPlainTextToolCallBlocks } from "../../../packages/tool-call-repair/src/index.js";
 import { resolveSessionAgentId } from "../../agents/agent-scope.js";
+import { resolveAgentIdentity, resolveResponsePrefix } from "../../agents/identity.js";
 import type { AgentToolResult } from "../../agents/runtime/index.js";
 import {
   readPositiveIntegerParam,
@@ -15,6 +16,7 @@ import {
 } from "../../agents/tools/common.js";
 import type { SourceReplyDeliveryMode } from "../../auto-reply/get-reply-options.types.js";
 import type { ReplyPayload } from "../../auto-reply/reply-payload.js";
+import { resolveResponsePrefixTemplate } from "../../auto-reply/reply/response-prefix-template.js";
 import { normalizeChatType, type ChatType } from "../../channels/chat-type.js";
 import type { InboundEventKind } from "../../channels/inbound-event/kind.js";
 import { getChannelPlugin } from "../../channels/plugins/index.js";
@@ -1044,6 +1046,10 @@ async function buildSendPayloadParts(params: {
   };
 }
 
+// Detects leftover `{variable}` placeholders after prefix interpolation. Non-global so
+// `.test()` stays stateless; mirrors the variable shape in response-prefix-template.ts.
+const UNRESOLVED_PREFIX_VAR_PATTERN = /\{[a-zA-Z][a-zA-Z0-9.]*\}/;
+
 async function handleSendAction(ctx: ResolvedActionContext): Promise<MessageActionRunResult> {
   const {
     cfg,
@@ -1070,6 +1076,37 @@ async function handleSendAction(ctx: ResolvedActionContext): Promise<MessageActi
     agentId,
   });
 
+  // `message(action=send)` crosses into other conversations, so mirror the direct-reply
+  // egress and prepend messages.responsePrefix here too; otherwise the disambiguation
+  // prefix is silently dropped on tool sends while replies keep it. Interpolate the
+  // template like normalize-reply.ts so identity tokens render. model/provider/thinking
+  // tokens need the live model selection that a tool send never performs, so when any
+  // placeholder stays unresolved we skip prefixing instead of leaking a literal `{model}`.
+  // The startsWith guard matches normalize-reply.ts and keeps re-runs idempotent.
+  const responsePrefix = resolveResponsePrefixTemplate(
+    resolveResponsePrefix(cfg, agentId ?? "", {
+      channel,
+      accountId: accountId ?? undefined,
+    }),
+    { identityName: normalizeOptionalString(resolveAgentIdentity(cfg, agentId ?? "")?.name) },
+  );
+  const prefixHasUnresolvedVar =
+    responsePrefix !== undefined && UNRESOLVED_PREFIX_VAR_PATTERN.test(responsePrefix);
+  if (
+    responsePrefix &&
+    !prefixHasUnresolvedVar &&
+    sendPayload.message &&
+    !sendPayload.message.startsWith(responsePrefix)
+  ) {
+    const prefixedMessage = `${responsePrefix} ${sendPayload.message}`;
+    sendPayload = {
+      ...sendPayload,
+      message: prefixedMessage,
+      payload: { ...sendPayload.payload, text: prefixedMessage },
+    };
+    applySendPayloadPartsToActionParams(params, sendPayload);
+  }
+
   const replyToIsExplicit = Boolean(readStringParam(params, "replyTo"));
   resolveAndApplyOutboundReplyToId(params, {
     channel,