diff --git a/extensions/slack/src/channel.test.ts b/extensions/slack/src/channel.test.ts
index 538bc8c7d03..e01776210a3 100644
--- a/extensions/slack/src/channel.test.ts
+++ b/extensions/slack/src/channel.test.ts
@@ -1043,6 +1043,9 @@ describe("slackPlugin agentPrompt", () => {
     expect(hints).toContain(
       "- Slack plain text sends: write standard Markdown; OpenClaw converts it to Slack mrkdwn, including `**bold**`, headings, lists, and `[label](url)` links.",
     );
+    expect(hints).toContain(
+      "- When mentioning Slack users, use the stable `<@USER_ID>` token from Slack context instead of plain `@name` text so Slack notifies and links the user.",
+    );
     expect(hints).toContain(
       "- Slack Block Kit or presentation text fields are sent as Slack mrkdwn directly; use `*bold*`, `_italic_`, `~strike~`, `<url|label>` links, and avoid Markdown headings or pipe tables there.",
     );
@@ -1073,6 +1076,9 @@ describe("slackPlugin agentPrompt", () => {
     expect(hints).toContain(
       "- Slack plain text sends: write standard Markdown; OpenClaw converts it to Slack mrkdwn, including `**bold**`, headings, lists, and `[label](url)` links.",
     );
+    expect(hints).toContain(
+      "- When mentioning Slack users, use the stable `<@USER_ID>` token from Slack context instead of plain `@name` text so Slack notifies and links the user.",
+    );
     expect(hints).toContain(
       "- Slack Block Kit or presentation text fields are sent as Slack mrkdwn directly; use `*bold*`, `_italic_`, `~strike~`, `<url|label>` links, and avoid Markdown headings or pipe tables there.",
     );
diff --git a/extensions/slack/src/shared.ts b/extensions/slack/src/shared.ts
index f62b13f4881..8d955427dd7 100644
--- a/extensions/slack/src/shared.ts
+++ b/extensions/slack/src/shared.ts
@@ -115,6 +115,7 @@ export function createSlackPluginBase(params: {
             ]
         ).concat([
           "- Slack plain text sends: write standard Markdown; OpenClaw converts it to Slack mrkdwn, including `**bold**`, headings, lists, and `[label](url)` links.",
+          "- When mentioning Slack users, use the stable `<@USER_ID>` token from Slack context instead of plain `@name` text so Slack notifies and links the user.",
           "- Slack Block Kit or presentation text fields are sent as Slack mrkdwn directly; use `*bold*`, `_italic_`, `~strike~`, `<url|label>` links, and avoid Markdown headings or pipe tables there.",
         ]),
     },