diff --git a/src/agents/cli-runner.ts b/src/agents/cli-runner.ts
index 30a456606..0f1b27e86 100644
--- a/src/agents/cli-runner.ts
+++ b/src/agents/cli-runner.ts
@@ -102,6 +102,7 @@ export async function runCliAgent(params: {
     tools: [],
     contextFiles,
     modelDisplay,
+    agentId: sessionAgentId,
   });
 
   const { sessionId: cliSessionIdToSend, isNew } = resolveSessionIdToSend({
diff --git a/src/agents/cli-runner/helpers.ts b/src/agents/cli-runner/helpers.ts
index e20602e0f..e079044b3 100644
--- a/src/agents/cli-runner/helpers.ts
+++ b/src/agents/cli-runner/helpers.ts
@@ -9,8 +9,8 @@ import type { ThinkLevel } from "../../auto-reply/thinking.js";
 import type { ClawdbotConfig } from "../../config/config.js";
 import type { CliBackendConfig } from "../../config/types.js";
 import { runExec } from "../../process/exec.js";
-import { formatUserTime, resolveUserTimeFormat, resolveUserTimezone } from "../date-time.js";
 import type { EmbeddedContextFile } from "../pi-embedded-helpers.js";
+import { buildSystemPromptParams } from "../system-prompt-params.js";
 import { buildAgentSystemPrompt } from "../system-prompt.js";
 
 const CLI_RUN_QUEUE = new Map<string, Promise<unknown>>();
@@ -172,10 +172,19 @@ export function buildSystemPrompt(params: {
   tools: AgentTool[];
   contextFiles?: EmbeddedContextFile[];
   modelDisplay: string;
+  agentId?: string;
 }) {
-  const userTimezone = resolveUserTimezone(params.config?.agents?.defaults?.userTimezone);
-  const userTimeFormat = resolveUserTimeFormat(params.config?.agents?.defaults?.timeFormat);
-  const userTime = formatUserTime(new Date(), userTimezone, userTimeFormat);
+  const { runtimeInfo, userTimezone, userTime, userTimeFormat } = buildSystemPromptParams({
+    config: params.config,
+    agentId: params.agentId,
+    runtime: {
+      host: "clawdbot",
+      os: `${os.type()} ${os.release()}`,
+      arch: os.arch(),
+      node: process.version,
+      model: params.modelDisplay,
+    },
+  });
   return buildAgentSystemPrompt({
     workspaceDir: params.workspaceDir,
     defaultThinkLevel: params.defaultThinkLevel,
@@ -184,13 +193,7 @@ export function buildSystemPrompt(params: {
     reasoningTagHint: false,
     heartbeatPrompt: params.heartbeatPrompt,
     docsPath: params.docsPath,
-    runtimeInfo: {
-      host: "clawdbot",
-      os: `${os.type()} ${os.release()}`,
-      arch: os.arch(),
-      node: process.version,
-      model: params.modelDisplay,
-    },
+    runtimeInfo,
     toolNames: params.tools.map((tool) => tool.name),
     modelAliasLines: buildModelAliasLines(params.config),
     userTimezone,
diff --git a/src/agents/pi-embedded-runner/run/attempt.ts b/src/agents/pi-embedded-runner/run/attempt.ts
index e89cd32b4..06272d7ce 100644
--- a/src/agents/pi-embedded-runner/run/attempt.ts
+++ b/src/agents/pi-embedded-runner/run/attempt.ts
@@ -64,7 +64,7 @@ import { prewarmSessionFile, trackSessionManagerAccess } from "../session-manage
 import { prepareSessionManagerForRun } from "../session-manager-init.js";
 import { buildEmbeddedSystemPrompt, createSystemPromptOverride } from "../system-prompt.js";
 import { splitSdkTools } from "../tool-split.js";
-import { formatUserTime, resolveUserTimeFormat, resolveUserTimezone } from "../../date-time.js";
+import { buildSystemPromptParams } from "../../system-prompt-params.js";
 import { describeUnknownError, mapThinkingLevel } from "../utils.js";
 import { resolveSandboxRuntimeStatus } from "../../sandbox/runtime-status.js";
 import { isTimeoutError } from "../../failover-error.js";
@@ -196,25 +196,25 @@ export async function runEmbeddedAttempt(
             return level ? { level, channel: "Telegram" } : undefined;
           })()
         : undefined;
-    const runtimeInfo = {
-      host: machineName,
-      os: `${os.type()} ${os.release()}`,
-      arch: os.arch(),
-      node: process.version,
-      model: `${params.provider}/${params.modelId}`,
-      channel: runtimeChannel,
-      capabilities: runtimeCapabilities,
-    };
-
-    const sandboxInfo = buildEmbeddedSandboxInfo(sandbox, params.bashElevated);
-    const reasoningTagHint = isReasoningTagProvider(params.provider);
-    const userTimezone = resolveUserTimezone(params.config?.agents?.defaults?.userTimezone);
-    const userTimeFormat = resolveUserTimeFormat(params.config?.agents?.defaults?.timeFormat);
-    const userTime = formatUserTime(new Date(), userTimezone, userTimeFormat);
     const { defaultAgentId, sessionAgentId } = resolveSessionAgentIds({
       sessionKey: params.sessionKey,
       config: params.config,
     });
+    const sandboxInfo = buildEmbeddedSandboxInfo(sandbox, params.bashElevated);
+    const reasoningTagHint = isReasoningTagProvider(params.provider);
+    const { runtimeInfo, userTimezone, userTime, userTimeFormat } = buildSystemPromptParams({
+      config: params.config,
+      agentId: sessionAgentId,
+      runtime: {
+        host: machineName,
+        os: `${os.type()} ${os.release()}`,
+        arch: os.arch(),
+        node: process.version,
+        model: `${params.provider}/${params.modelId}`,
+        channel: runtimeChannel,
+        capabilities: runtimeCapabilities,
+      },
+    });
     const isDefaultAgent = sessionAgentId === defaultAgentId;
     const promptMode = isSubagentSessionKey(params.sessionKey) ? "minimal" : "full";
     const docsPath = await resolveClawdbotDocsPath({
diff --git a/src/agents/pi-embedded-runner/system-prompt.ts b/src/agents/pi-embedded-runner/system-prompt.ts
index 3cbbed6db..40f3e7a4b 100644
--- a/src/agents/pi-embedded-runner/system-prompt.ts
+++ b/src/agents/pi-embedded-runner/system-prompt.ts
@@ -23,6 +23,7 @@ export function buildEmbeddedSystemPrompt(params: {
   /** Controls which hardcoded sections to include. Defaults to "full". */
   promptMode?: PromptMode;
   runtimeInfo: {
+    agentId?: string;
     host: string;
     os: string;
     arch: string;
diff --git a/src/agents/system-prompt-params.ts b/src/agents/system-prompt-params.ts
new file mode 100644
index 000000000..7a076a139
--- /dev/null
+++ b/src/agents/system-prompt-params.ts
@@ -0,0 +1,44 @@
+import type { ClawdbotConfig } from "../config/config.js";
+import {
+  formatUserTime,
+  resolveUserTimeFormat,
+  resolveUserTimezone,
+  type ResolvedTimeFormat,
+} from "./date-time.js";
+
+export type RuntimeInfoInput = {
+  agentId?: string;
+  host: string;
+  os: string;
+  arch: string;
+  node: string;
+  model: string;
+  channel?: string;
+  capabilities?: string[];
+};
+
+export type SystemPromptRuntimeParams = {
+  runtimeInfo: RuntimeInfoInput;
+  userTimezone: string;
+  userTime?: string;
+  userTimeFormat?: ResolvedTimeFormat;
+};
+
+export function buildSystemPromptParams(params: {
+  config?: ClawdbotConfig;
+  agentId?: string;
+  runtime: Omit<RuntimeInfoInput, "agentId">;
+}): SystemPromptRuntimeParams {
+  const userTimezone = resolveUserTimezone(params.config?.agents?.defaults?.userTimezone);
+  const userTimeFormat = resolveUserTimeFormat(params.config?.agents?.defaults?.timeFormat);
+  const userTime = formatUserTime(new Date(), userTimezone, userTimeFormat);
+  return {
+    runtimeInfo: {
+      agentId: params.agentId,
+      ...params.runtime,
+    },
+    userTimezone,
+    userTime,
+    userTimeFormat,
+  };
+}
diff --git a/src/agents/system-prompt.test.ts b/src/agents/system-prompt.test.ts
index 06570f6ff..17303d0e9 100644
--- a/src/agents/system-prompt.test.ts
+++ b/src/agents/system-prompt.test.ts
@@ -1,5 +1,5 @@
 import { describe, expect, it } from "vitest";
-import { buildAgentSystemPrompt } from "./system-prompt.js";
+import { buildAgentSystemPrompt, buildRuntimeLine } from "./system-prompt.js";
 
 describe("buildAgentSystemPrompt", () => {
   it("includes owner numbers when provided", () => {
@@ -252,6 +252,22 @@ describe("buildAgentSystemPrompt", () => {
     expect(prompt).toContain("capabilities=inlineButtons");
   });
 
+  it("includes agent id in runtime when provided", () => {
+    const prompt = buildAgentSystemPrompt({
+      workspaceDir: "/tmp/clawd",
+      runtimeInfo: {
+        agentId: "work",
+        host: "host",
+        os: "macOS",
+        arch: "arm64",
+        node: "v20",
+        model: "anthropic/claude",
+      },
+    });
+
+    expect(prompt).toContain("agent=work");
+  });
+
   it("includes reasoning visibility hint", () => {
     const prompt = buildAgentSystemPrompt({
       workspaceDir: "/tmp/clawd",
@@ -263,6 +279,31 @@ describe("buildAgentSystemPrompt", () => {
     expect(prompt).toContain("/status shows Reasoning");
   });
 
+  it("builds runtime line with agent and channel details", () => {
+    const line = buildRuntimeLine(
+      {
+        agentId: "work",
+        host: "host",
+        os: "macOS",
+        arch: "arm64",
+        node: "v20",
+        model: "anthropic/claude",
+      },
+      "telegram",
+      ["inlineButtons"],
+      "low",
+    );
+
+    expect(line).toContain("agent=work");
+    expect(line).toContain("host=host");
+    expect(line).toContain("os=macOS (arm64)");
+    expect(line).toContain("node=v20");
+    expect(line).toContain("model=anthropic/claude");
+    expect(line).toContain("channel=telegram");
+    expect(line).toContain("capabilities=inlineButtons");
+    expect(line).toContain("thinking=low");
+  });
+
   it("describes sandboxed runtime and elevated when allowed", () => {
     const prompt = buildAgentSystemPrompt({
       workspaceDir: "/tmp/clawd",
diff --git a/src/agents/system-prompt.ts b/src/agents/system-prompt.ts
index 19ba1bfc6..40ecd8607 100644
--- a/src/agents/system-prompt.ts
+++ b/src/agents/system-prompt.ts
@@ -149,6 +149,7 @@ export function buildAgentSystemPrompt(params: {
   /** Controls which hardcoded sections to include. Defaults to "full". */
   promptMode?: PromptMode;
   runtimeInfo?: {
+    agentId?: string;
     host?: string;
     os?: string;
     arch?: string;
@@ -546,27 +547,40 @@ export function buildAgentSystemPrompt(params: {
     );
   }
 
-  lines.push(
-    "## Runtime",
-    `Runtime: ${[
-      runtimeInfo?.host ? `host=${runtimeInfo.host}` : "",
-      runtimeInfo?.os
-        ? `os=${runtimeInfo.os}${runtimeInfo?.arch ? ` (${runtimeInfo.arch})` : ""}`
-        : runtimeInfo?.arch
-          ? `arch=${runtimeInfo.arch}`
-          : "",
-      runtimeInfo?.node ? `node=${runtimeInfo.node}` : "",
-      runtimeInfo?.model ? `model=${runtimeInfo.model}` : "",
-      runtimeChannel ? `channel=${runtimeChannel}` : "",
-      runtimeChannel
-        ? `capabilities=${runtimeCapabilities.length > 0 ? runtimeCapabilities.join(",") : "none"}`
-        : "",
-      `thinking=${params.defaultThinkLevel ?? "off"}`,
-    ]
-      .filter(Boolean)
-      .join(" | ")}`,
-    `Reasoning: ${reasoningLevel} (hidden unless on/stream). Toggle /reasoning; /status shows Reasoning when enabled.`,
-  );
+  lines.push("## Runtime", buildRuntimeLine(runtimeInfo, runtimeChannel, runtimeCapabilities, params.defaultThinkLevel), `Reasoning: ${reasoningLevel} (hidden unless on/stream). Toggle /reasoning; /status shows Reasoning when enabled.`);
 
   return lines.filter(Boolean).join("\n");
 }
+
+export function buildRuntimeLine(
+  runtimeInfo: {
+    agentId?: string;
+    host?: string;
+    os?: string;
+    arch?: string;
+    node?: string;
+    model?: string;
+  },
+  runtimeChannel?: string,
+  runtimeCapabilities: string[] = [],
+  defaultThinkLevel?: ThinkLevel,
+): string {
+  return `Runtime: ${[
+    runtimeInfo?.agentId ? `agent=${runtimeInfo.agentId}` : "",
+    runtimeInfo?.host ? `host=${runtimeInfo.host}` : "",
+    runtimeInfo?.os
+      ? `os=${runtimeInfo.os}${runtimeInfo?.arch ? ` (${runtimeInfo.arch})` : ""}`
+      : runtimeInfo?.arch
+        ? `arch=${runtimeInfo.arch}`
+        : "",
+    runtimeInfo?.node ? `node=${runtimeInfo.node}` : "",
+    runtimeInfo?.model ? `model=${runtimeInfo.model}` : "",
+    runtimeChannel ? `channel=${runtimeChannel}` : "",
+    runtimeChannel
+      ? `capabilities=${runtimeCapabilities.length > 0 ? runtimeCapabilities.join(",") : "none"}`
+      : "",
+    `thinking=${defaultThinkLevel ?? "off"}`,
+  ]
+    .filter(Boolean)
+    .join(" | ")}`;
+}