diff --git a/molecule_runtime/adapters/shared_runtime.py b/molecule_runtime/adapters/shared_runtime.py
index a383866..97df11a 100644
--- a/molecule_runtime/adapters/shared_runtime.py
+++ b/molecule_runtime/adapters/shared_runtime.py
@@ -153,20 +153,18 @@ def brief_task(text: str, limit: int = 60) -> str:
 async def set_current_task(heartbeat: Any, task: str) -> None:
     """Update current task on heartbeat and push immediately to platform.
 
-    The heartbeat loop only fires every 30s, so quick tasks would finish
-    before the canvas ever sees them. Setting a task pushes immediately.
-    Clearing a task only updates the heartbeat object — the next heartbeat
-    cycle will broadcast the clear, keeping the task visible longer.
+    Uses increment/decrement instead of binary 0/1 so agents can track
+    multiple concurrent tasks (#1408). Pushes immediately on both
+    increment and decrement to avoid phantom-busy (#1372).
     """
     if heartbeat:
-        heartbeat.current_task = task
-        heartbeat.active_tasks = 1 if task else 0
-
-    # Only push immediately when SETTING a task (not clearing)
-    # Clearing is handled by the next heartbeat cycle, which keeps
-    # the task visible on the canvas for quick A2A responses
-    if not task:
-        return
+        if task:
+            heartbeat.active_tasks = getattr(heartbeat, "active_tasks", 0) + 1
+            heartbeat.current_task = task
+        else:
+            heartbeat.active_tasks = max(0, getattr(heartbeat, "active_tasks", 0) - 1)
+            if heartbeat.active_tasks == 0:
+                heartbeat.current_task = ""
 
     import os
     workspace_id = os.environ.get("WORKSPACE_ID", "")
@@ -174,13 +172,15 @@ async def set_current_task(heartbeat: Any, task: str) -> None:
     if workspace_id and platform_url:
         try:
             import httpx
+            active = getattr(heartbeat, "active_tasks", 0) if heartbeat else (1 if task else 0)
+            cur_task = getattr(heartbeat, "current_task", task or "") if heartbeat else (task or "")
             async with httpx.AsyncClient(timeout=3.0) as client:
                 await client.post(
                     f"{platform_url}/registry/heartbeat",
                     json={
                         "workspace_id": workspace_id,
-                        "current_task": task,
-                        "active_tasks": 1,
+                        "current_task": cur_task,
+                        "active_tasks": active,
                         "error_rate": 0,
                         "sample_error": "",
                         "uptime_seconds": 0,
diff --git a/molecule_runtime/executor_helpers.py b/molecule_runtime/executor_helpers.py
index 19fb4a5..9d6b993 100644
--- a/molecule_runtime/executor_helpers.py
+++ b/molecule_runtime/executor_helpers.py
@@ -223,14 +223,26 @@ def read_delegation_results() -> str:
 # ========================================================================
 
 async def set_current_task(heartbeat: "HeartbeatLoop | None", task: str) -> None:
-    """Update current task on heartbeat and push immediately via platform API."""
+    """Update current task on heartbeat and push immediately via platform API.
+
+    Uses increment/decrement instead of binary 0/1 so agents can track
+    multiple concurrent tasks (#1408). Pushes immediately on both
+    increment and decrement to avoid phantom-busy (#1372).
+    """
     if heartbeat is not None:
-        heartbeat.current_task = task
-        heartbeat.active_tasks = 1 if task else 0
+        if task:
+            heartbeat.active_tasks = getattr(heartbeat, "active_tasks", 0) + 1
+            heartbeat.current_task = task
+        else:
+            heartbeat.active_tasks = max(0, getattr(heartbeat, "active_tasks", 0) - 1)
+            if heartbeat.active_tasks == 0:
+                heartbeat.current_task = ""
     workspace_id = os.environ.get("WORKSPACE_ID", "")
     platform_url = os.environ.get("PLATFORM_URL", "")
     if not (workspace_id and platform_url):
         return
+    active = getattr(heartbeat, "active_tasks", 0) if heartbeat is not None else (1 if task else 0)
+    cur_task = getattr(heartbeat, "current_task", task or "") if heartbeat is not None else (task or "")
     try:
         try:
             from platform_auth import auth_headers as _auth
@@ -241,8 +253,8 @@ async def set_current_task(heartbeat: "HeartbeatLoop | None", task: str) -> None
             f"{platform_url}/registry/heartbeat",
             json={
                 "workspace_id": workspace_id,
-                "current_task": task,
-                "active_tasks": 1 if task else 0,
+                "current_task": cur_task,
+                "active_tasks": active,
                 "error_rate": 0,
                 "sample_error": "",
                 "uptime_seconds": 0,
diff --git a/pyproject.toml b/pyproject.toml
index e8a1968..9b80103 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -4,7 +4,7 @@ build-backend = "setuptools.build_meta"
 
 [project]
 name = "molecule-ai-workspace-runtime"
-version = "0.1.2"
+version = "0.1.3"
 description = "Molecule AI workspace runtime — shared infrastructure for all agent adapters"
 requires-python = ">=3.11"
 license = {text = "BSL-1.1"}