diff --git a/CHANGELOG.md b/CHANGELOG.md
index 9e507fa8fed..fb715bc5ed0 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -31,6 +31,7 @@ Docs: https://docs.openclaw.ai
 - Discord/native commands: compare Discord-normalized slash-command descriptions and localized descriptions during reconcile so CJK or multiline command text no longer triggers redundant startup PATCH bursts and rate-limit 429s. Fixes #76587. Thanks @zhengsx.
 - Agents/OpenAI: omit Chat Completions `reasoning_effort` for `gpt-5.4-mini` only when function tools are present while preserving tool-free Chat and Responses reasoning support, preventing Telegram-routed fallback runs from hanging after OpenAI rejects tool payloads. Fixes #76176. Thanks @ThisIsAdilah and @chinar-amrutkar.
 - Telegram: reuse the successful startup `getMe` probe for grammY polling startup and continue into `getUpdates` after recoverable `deleteWebhook` cleanup failures, reducing high-latency Bot API control-plane calls before long polling starts. Refs #76388. Thanks @jackiedepp.
+- Gateway/diagnostics: merge session id/key aliases in diagnostic session state and activity tracking so completed runs no longer leave stale queued work behind that keeps liveness samples at warning level.
 - Agents/models: forward model `maxTokens` as the default output-token limit for OpenAI-compatible Responses and Completions transports when no runtime override is provided, preventing provider defaults from silently truncating larger outputs. (#76645) Thanks @joeyfrasier.
 - macOS CLI/onboarding: honor sensitive wizard text steps in `openclaw-mac wizard` with termios no-echo input, suppressing saved credential previews while preserving long API keys and gateway tokens. Fixes #76698. Thanks @anurag-bg-neu and @sallyom.
 - Control UI/Skills: fix skill detail modal silently failing to open in all browsers by deferring `showModal()` until the dialog element is connected to the DOM; the Lit `ref` callback fired before connection causing a `DOMException: HTMLDialogElement.showModal: Dialog element is not connected` on every skill click. Thanks @nickmopen.
diff --git a/src/logging/diagnostic-run-activity.ts b/src/logging/diagnostic-run-activity.ts
index 5f1c1fe7671..f8155e94fcb 100644
--- a/src/logging/diagnostic-run-activity.ts
+++ b/src/logging/diagnostic-run-activity.ts
@@ -46,34 +46,86 @@ function sessionRefs(params: { sessionId?: string; sessionKey?: string }): strin
   return refs;
 }
 
+function registerSessionActivityRefs(
+  activity: SessionActivity,
+  params: { sessionId?: string; sessionKey?: string; runId?: string },
+): void {
+  activity.sessionId ??= params.sessionId;
+  activity.sessionKey ??= params.sessionKey;
+  for (const ref of sessionRefs(params)) {
+    activityByRef.set(ref, activity);
+  }
+  if (params.runId) {
+    activityByRunId.set(params.runId, activity);
+  }
+}
+
+function replaceSessionActivityReferences(source: SessionActivity, target: SessionActivity): void {
+  for (const [ref, activity] of activityByRef) {
+    if (activity === source) {
+      activityByRef.set(ref, target);
+    }
+  }
+  for (const [runId, activity] of activityByRunId) {
+    if (activity === source) {
+      activityByRunId.set(runId, target);
+    }
+  }
+}
+
+function mergeSessionActivity(target: SessionActivity, source: SessionActivity): void {
+  target.sessionId ??= source.sessionId;
+  target.sessionKey ??= source.sessionKey;
+  target.activeEmbeddedRun ||= source.activeEmbeddedRun;
+  for (const [key, tool] of source.activeTools) {
+    target.activeTools.set(key, tool);
+  }
+  for (const call of source.activeModelCalls) {
+    target.activeModelCalls.add(call);
+  }
+  if (source.lastProgressAt > target.lastProgressAt) {
+    target.lastProgressAt = source.lastProgressAt;
+    target.lastProgressReason = source.lastProgressReason;
+  }
+  replaceSessionActivityReferences(source, target);
+}
+
 function resolveSessionActivity(params: {
   sessionId?: string;
   sessionKey?: string;
   runId?: string;
   create?: boolean;
 }): SessionActivity | undefined {
+  let activity: SessionActivity | undefined;
   if (params.runId) {
     const byRun = activityByRunId.get(params.runId);
     if (byRun) {
-      return byRun;
+      activity = byRun;
     }
   }
 
   for (const ref of sessionRefs(params)) {
-    const activity = activityByRef.get(ref);
-    if (activity) {
-      if (params.runId) {
-        activityByRunId.set(params.runId, activity);
-      }
-      return activity;
+    const byRef = activityByRef.get(ref);
+    if (!byRef) {
+      continue;
     }
+    if (!activity) {
+      activity = byRef;
+    } else if (activity !== byRef) {
+      mergeSessionActivity(activity, byRef);
+    }
+  }
+
+  if (activity) {
+    registerSessionActivityRefs(activity, params);
+    return activity;
   }
 
   if (!params.create) {
     return undefined;
   }
 
-  const activity: SessionActivity = {
+  const created: SessionActivity = {
     sessionId: params.sessionId,
     sessionKey: params.sessionKey,
     activeEmbeddedRun: false,
@@ -81,13 +133,8 @@ function resolveSessionActivity(params: {
     activeModelCalls: new Set(),
     lastProgressAt: Date.now(),
   };
-  for (const ref of sessionRefs(params)) {
-    activityByRef.set(ref, activity);
-  }
-  if (params.runId) {
-    activityByRunId.set(params.runId, activity);
-  }
-  return activity;
+  registerSessionActivityRefs(created, params);
+  return created;
 }
 
 function touchSessionActivity(activity: SessionActivity, reason: string, now = Date.now()): void {
diff --git a/src/logging/diagnostic-session-state.ts b/src/logging/diagnostic-session-state.ts
index 69a70681213..edc2e98d14c 100644
--- a/src/logging/diagnostic-session-state.ts
+++ b/src/logging/diagnostic-session-state.ts
@@ -70,21 +70,75 @@ function resolveSessionKey({ sessionKey, sessionId }: SessionRef) {
   return sessionKey ?? sessionId ?? "unknown";
 }
 
-function findStateBySessionId(sessionId: string): SessionState | undefined {
-  for (const state of diagnosticSessionStates.values()) {
+function findStateEntryBySessionId(sessionId: string): [string, SessionState] | undefined {
+  for (const entry of diagnosticSessionStates.entries()) {
+    const [, state] = entry;
     if (state.sessionId === sessionId) {
-      return state;
+      return entry;
     }
   }
   return undefined;
 }
 
+function sessionStatePriority(state: SessionStateValue): number {
+  const priorities = {
+    idle: 0,
+    waiting: 1,
+    processing: 2,
+  } satisfies Record<SessionStateValue, number>;
+  return priorities[state];
+}
+
+function mergeSessionState(target: SessionState, source: SessionState): void {
+  const sourceIsNewer = source.lastActivity > target.lastActivity;
+  const sourceIsSameAgeAndMoreActive =
+    source.lastActivity === target.lastActivity &&
+    sessionStatePriority(source.state) > sessionStatePriority(target.state);
+  target.sessionId ??= source.sessionId;
+  target.sessionKey ??= source.sessionKey;
+  if (sourceIsNewer || sourceIsSameAgeAndMoreActive) {
+    target.state = source.state;
+  }
+  target.lastActivity = Math.max(target.lastActivity, source.lastActivity);
+  target.queueDepth += source.queueDepth;
+  target.lastStuckWarnAgeMs =
+    target.lastStuckWarnAgeMs === undefined || source.lastStuckWarnAgeMs === undefined
+      ? undefined
+      : Math.max(target.lastStuckWarnAgeMs, source.lastStuckWarnAgeMs);
+  if (source.toolCallHistory?.length) {
+    target.toolCallHistory = [...(target.toolCallHistory ?? []), ...source.toolCallHistory];
+  }
+  if (source.toolLoopWarningBuckets?.size) {
+    const buckets = (target.toolLoopWarningBuckets ??= new Map());
+    for (const [bucket, count] of source.toolLoopWarningBuckets) {
+      buckets.set(bucket, Math.max(buckets.get(bucket) ?? 0, count));
+    }
+  }
+  if (source.commandPollCounts?.size) {
+    const counts = (target.commandPollCounts ??= new Map());
+    for (const [command, value] of source.commandPollCounts) {
+      const existing = counts.get(command);
+      if (!existing || value.lastPollAt > existing.lastPollAt) {
+        counts.set(command, value);
+      }
+    }
+  }
+}
+
 export function getDiagnosticSessionState(ref: SessionRef): SessionState {
   pruneDiagnosticSessionStates();
   const key = resolveSessionKey(ref);
-  const existing =
-    diagnosticSessionStates.get(key) ?? (ref.sessionId && findStateBySessionId(ref.sessionId));
+  const direct = diagnosticSessionStates.get(key);
+  const sessionIdEntry = ref.sessionId ? findStateEntryBySessionId(ref.sessionId) : undefined;
+  const existing = direct ?? sessionIdEntry?.[1];
   if (existing) {
+    if (direct && sessionIdEntry && sessionIdEntry[1] !== direct) {
+      mergeSessionState(direct, sessionIdEntry[1]);
+      diagnosticSessionStates.delete(sessionIdEntry[0]);
+    } else if (!direct && ref.sessionKey && sessionIdEntry) {
+      diagnosticSessionStates.delete(sessionIdEntry[0]);
+      diagnosticSessionStates.set(key, existing);
+    }
     if (ref.sessionId) {
       existing.sessionId = ref.sessionId;
     }
diff --git a/src/logging/diagnostic.test.ts b/src/logging/diagnostic.test.ts
index 2893cccadf6..831b8cc6c50 100644
--- a/src/logging/diagnostic.test.ts
+++ b/src/logging/diagnostic.test.ts
@@ -8,7 +8,10 @@ import {
   setDiagnosticsEnabledForProcess,
   type DiagnosticEventPayload,
 } from "../infra/diagnostic-events.js";
-import { markDiagnosticEmbeddedRunStarted } from "./diagnostic-run-activity.js";
+import {
+  getDiagnosticSessionActivitySnapshot,
+  markDiagnosticEmbeddedRunStarted,
+} from "./diagnostic-run-activity.js";
 import {
   diagnosticSessionStates,
   getDiagnosticSessionStateCountForTest,
@@ -93,6 +96,70 @@ describe("diagnostic session state pruning", () => {
     expect(bySessionId.sessionKey).toBe("agent:main:demo-channel:channel:c1");
     expect(getDiagnosticSessionStateCountForTest()).toBe(1);
   });
+
+  it("canonicalizes sessionId-only state when the sessionKey becomes known", () => {
+    const sessionKey = "agent:main:demo-channel:channel:c1";
+    const pending = getDiagnosticSessionState({ sessionId: "s1" });
+    pending.queueDepth = 1;
+
+    const keyed = getDiagnosticSessionState({ sessionId: "s1", sessionKey });
+
+    expect(keyed).toBe(pending);
+    expect(keyed.queueDepth).toBe(1);
+    expect(diagnosticSessionStates.has("s1")).toBe(false);
+    expect(diagnosticSessionStates.get(sessionKey)).toBe(keyed);
+    expect(getDiagnosticSessionState({ sessionKey })).toBe(keyed);
+    expect(getDiagnosticSessionStateCountForTest()).toBe(1);
+  });
+
+  it("merges split sessionId and sessionKey state without leaving stale queued work", () => {
+    const sessionKey = "agent:main:demo-channel:channel:c1";
+    const keyed = getDiagnosticSessionState({ sessionKey });
+    keyed.queueDepth = 1;
+    keyed.lastActivity = 1;
+    const bySessionId = getDiagnosticSessionState({ sessionId: "s1" });
+    bySessionId.queueDepth = 1;
+    bySessionId.state = "processing";
+    bySessionId.lastActivity = 2;
+
+    const merged = getDiagnosticSessionState({ sessionId: "s1", sessionKey });
+
+    expect(merged).toBe(keyed);
+    expect(merged.queueDepth).toBe(2);
+    expect(merged.state).toBe("processing");
+    expect(diagnosticSessionStates.has("s1")).toBe(false);
+    expect(getDiagnosticSessionStateCountForTest()).toBe(1);
+
+    logSessionStateChange({ sessionId: "s1", sessionKey, state: "idle", reason: "run_completed" });
+    logSessionStateChange({ sessionKey, state: "idle", reason: "message_completed" });
+
+    expect(getDiagnosticSessionState({ sessionKey }).queueDepth).toBe(0);
+    expect(getDiagnosticSessionStateCountForTest()).toBe(1);
+  });
+});
+
+describe("diagnostic session activity aliases", () => {
+  beforeEach(() => {
+    resetDiagnosticStateForTest();
+  });
+
+  afterEach(() => {
+    resetDiagnosticStateForTest();
+  });
+
+  it("registers the sessionKey alias when activity first arrives with only a sessionId", () => {
+    const sessionKey = "agent:main:demo-channel:channel:c1";
+
+    markDiagnosticEmbeddedRunStarted({ sessionId: "s1" });
+    markDiagnosticEmbeddedRunStarted({ sessionId: "s1", sessionKey });
+
+    expect(getDiagnosticSessionActivitySnapshot({ sessionKey }).activeWorkKind).toBe(
+      "embedded_run",
+    );
+    expect(getDiagnosticSessionActivitySnapshot({ sessionId: "s1" }).activeWorkKind).toBe(
+      "embedded_run",
+    );
+  });
 });
 
 describe("logger import side effects", () => {