diff --git a/comfy_execution/jobs.py b/comfy_execution/jobs.py
index fcd7ef735..24dd1ffd0 100644
--- a/comfy_execution/jobs.py
+++ b/comfy_execution/jobs.py
@@ -93,6 +93,27 @@ def _create_text_preview(value: str) -> dict:
     }
 
 
+def extract_workflow_id(extra_data: Optional[dict]) -> Optional[str]:
+    """Extract the workflow id from a prompt's ``extra_data``.
+
+    The frontend stores the id at ``extra_data["extra_pnginfo"]["workflow"]["id"]``
+    when a prompt is queued. Any value that is not a non-empty string is treated as
+    missing so callers can rely on the return being either ``None`` or a string.
+    """
+    if not isinstance(extra_data, dict):
+        return None
+    extra_pnginfo = extra_data.get('extra_pnginfo')
+    if not isinstance(extra_pnginfo, dict):
+        return None
+    workflow = extra_pnginfo.get('workflow')
+    if not isinstance(workflow, dict):
+        return None
+    workflow_id = workflow.get('id')
+    if isinstance(workflow_id, str) and workflow_id:
+        return workflow_id
+    return None
+
+
 def _extract_job_metadata(extra_data: dict) -> tuple[Optional[int], Optional[str]]:
     """Extract create_time and workflow_id from extra_data.
 
@@ -100,8 +121,7 @@ def _extract_job_metadata(extra_data: dict) -> tuple[Optional[int], Optional[str
         tuple: (create_time, workflow_id)
     """
     create_time = extra_data.get('create_time')
-    extra_pnginfo = extra_data.get('extra_pnginfo', {})
-    workflow_id = extra_pnginfo.get('workflow', {}).get('id')
+    workflow_id = extract_workflow_id(extra_data)
     return create_time, workflow_id
 
 
diff --git a/comfy_execution/metadata.py b/comfy_execution/metadata.py
new file mode 100644
index 000000000..583e2bdb8
--- /dev/null
+++ b/comfy_execution/metadata.py
@@ -0,0 +1,86 @@
+"""Per-prompt metadata propagated alongside execution WebSocket events.
+
+The execution layer (``execution.py``) is intentionally kept agnostic of
+workflow-level concepts. ``PromptServer`` registers metadata at submission time
+and merges it onto outgoing WebSocket payloads in ``send_sync``. Today only
+``workflow_id`` is propagated; the structure is a ``TypedDict`` so additional
+keys can be added without churn at the call sites.
+
+Identity model — registry is keyed by an internal monotonic token, NOT by
+``prompt_id``. ``post_prompt`` accepts a client-supplied ``prompt_id``
+verbatim, so two prompts can be queued with the same id and a registry keyed
+only by ``prompt_id`` would misattribute events when queue order differs from
+registration order. ``main.py``'s queue worker pins the active token on the
+server for the duration of one prompt's execution and ``send_sync`` reads that
+token — so each prompt's events get its own registered metadata regardless of
+``prompt_id`` collisions.
+"""
+
+import threading
+from typing import Optional, TypedDict
+
+from comfy_execution.jobs import extract_workflow_id
+
+
+PROMPT_METADATA_TOKEN_KEY = "__prompt_metadata_token"
+
+
+class PromptMetadata(TypedDict, total=False):
+    workflow_id: Optional[str]
+
+
+def build_prompt_metadata(extra_data: Optional[dict]) -> PromptMetadata:
+    """Build a ``PromptMetadata`` snapshot from a prompt's ``extra_data``.
+
+    Returns an empty dict when no recognized metadata is present so callers can
+    skip registering anything in that case.
+    """
+    meta: PromptMetadata = {}
+    workflow_id = extract_workflow_id(extra_data)
+    if workflow_id is not None:
+        meta["workflow_id"] = workflow_id
+    return meta
+
+
+def resolve_progress_text_sid(sid, default_sid):
+    """Pick the recipient for a ``send_progress_text`` binary frame.
+
+    Returns ``default_sid`` (typically ``PromptServer.client_id`` — the client
+    that submitted the active prompt) when the caller didn't pin a specific
+    socket. This narrows the audience for text status updates from "every
+    connected client" to "the client running this prompt", matching the
+    cross-client isolation other execution events already have.
+
+    Splitting this out keeps the unit test independent of the full ``server``
+    import chain.
+    """
+    return default_sid if sid is None else sid
+
+
+def merge_prompt_metadata(
+    registry: dict,
+    lock: threading.Lock,
+    active_token: Optional[int],
+    data,
+):
+    """Return ``data`` with the metadata for the currently-active token merged
+    top-level. The event payload wins on conflict, and non-dict payloads (e.g.
+    the binary preview tuple) pass through untouched.
+
+    The active token is set by ``main.py``'s queue worker around each
+    ``e.execute(...)``. The merge happens only when a token is currently active
+    *and* the payload carries a ``prompt_id`` — using ``prompt_id`` purely as a
+    marker that this is an execution event meant to receive metadata, not as
+    the lookup key. This makes the merge immune to ``prompt_id`` collisions.
+    """
+    if not isinstance(data, dict):
+        return data
+    if not data.get("prompt_id"):
+        return data
+    if active_token is None:
+        return data
+    with lock:
+        meta = registry.get(active_token)
+    if not meta:
+        return data
+    return {**meta, **data}
diff --git a/comfy_execution/progress.py b/comfy_execution/progress.py
index f951a3350..a4d8c56b6 100644
--- a/comfy_execution/progress.py
+++ b/comfy_execution/progress.py
@@ -159,11 +159,19 @@ class WebUIProgressHandler(ProgressHandler):
     def set_registry(self, registry: "ProgressRegistry"):
         self.registry = registry
 
+    def _lookup_workflow_id(self, prompt_id: str) -> Optional[str]:
+        get_meta = getattr(self.server_instance, "get_active_prompt_metadata", None)
+        if get_meta is None:
+            return None
+        return get_meta().get("workflow_id")
+
     def _send_progress_state(self, prompt_id: str, nodes: Dict[str, NodeProgressState]):
         """Send the current progress state to the client"""
         if self.server_instance is None:
             return
 
+        workflow_id = self._lookup_workflow_id(prompt_id)
+
         # Only send info for non-pending nodes
         active_nodes = {
             node_id: {
@@ -172,6 +180,7 @@ class WebUIProgressHandler(ProgressHandler):
                 "state": state["state"].value,
                 "node_id": node_id,
                 "prompt_id": prompt_id,
+                "workflow_id": workflow_id,
                 "display_node_id": self.registry.dynprompt.get_display_node_id(node_id),
                 "parent_node_id": self.registry.dynprompt.get_parent_node_id(node_id),
                 "real_node_id": self.registry.dynprompt.get_real_node_id(node_id),
@@ -181,7 +190,10 @@ class WebUIProgressHandler(ProgressHandler):
         }
 
         # Send a combined progress_state message with all node states
-        # Include client_id to ensure message is only sent to the initiating client
+        # Include client_id to ensure message is only sent to the initiating client.
+        # The outer ``workflow_id`` is merged in by ``PromptServer.send_sync`` via
+        # the per-prompt metadata registry; the nested copy on each node entry
+        # mirrors the wire shape consumed by the frontend.
         self.server_instance.send_sync(
             "progress_state", {"prompt_id": prompt_id, "nodes": active_nodes}, self.server_instance.client_id
         )
@@ -215,6 +227,7 @@ class WebUIProgressHandler(ProgressHandler):
                 metadata = {
                     "node_id": node_id,
                     "prompt_id": prompt_id,
+                    "workflow_id": self._lookup_workflow_id(prompt_id),
                     "display_node_id": self.registry.dynprompt.get_display_node_id(
                         node_id
                     ),
diff --git a/execution.py b/execution.py
index 4c7de2e84..00a81e335 100644
--- a/execution.py
+++ b/execution.py
@@ -36,6 +36,7 @@ from comfy_execution.graph import (
     get_input_info,
 )
 from comfy_execution.graph_utils import GraphBuilder, is_link
+from comfy_execution.metadata import PROMPT_METADATA_TOKEN_KEY
 from comfy_execution.validation import validate_node_input
 from comfy_execution.progress import get_progress_state, reset_progress_state, add_progress_handler, WebUIProgressHandler
 from comfy_execution.utils import CurrentNodeContext
@@ -1294,20 +1295,32 @@ class PromptQueue:
         with self.mutex:
             return len(self.queue) + len(self.currently_running)
 
+    def _extract_metadata_token(self, item):
+        # Queue item shape: (number, prompt_id, prompt, extra_data, outputs, sensitive)
+        extra_data = item[3] if len(item) > 3 and isinstance(item[3], dict) else None
+        if not extra_data:
+            return None
+        return extra_data.get(PROMPT_METADATA_TOKEN_KEY)
+
     def wipe_queue(self):
         with self.mutex:
+            cancelled_tokens = [self._extract_metadata_token(item) for item in self.queue]
             self.queue = []
             self.server.queue_updated()
+        for token in cancelled_tokens:
+            self.server.unregister_prompt_metadata(token)
 
     def delete_queue_item(self, function):
         with self.mutex:
             for x in range(len(self.queue)):
                 if function(self.queue[x]):
+                    cancelled_token = self._extract_metadata_token(self.queue[x])
                     if len(self.queue) == 1:
                         self.wipe_queue()
                     else:
                         self.queue.pop(x)
                         heapq.heapify(self.queue)
+                        self.server.unregister_prompt_metadata(cancelled_token)
                     self.server.queue_updated()
                     return True
         return False
diff --git a/main.py b/main.py
index a6fdaf43c..5ccd4daae 100644
--- a/main.py
+++ b/main.py
@@ -27,6 +27,7 @@ from utils.mime_types import init_mime_types
 import faulthandler
 import logging
 import sys
+from comfy_execution.metadata import PROMPT_METADATA_TOKEN_KEY
 from comfy_execution.progress import get_progress_state
 from comfy_execution.utils import get_executing_context
 from comfy_api import feature_flags
@@ -317,20 +318,34 @@ def prompt_worker(q, server_instance):
             for k in sensitive:
                 extra_data[k] = sensitive[k]
 
+            # Pin the metadata token registered for this exact prompt while it
+            # runs so ``send_sync`` can decorate its frames with the right
+            # ``workflow_id`` even if another submission shares the same
+            # ``prompt_id``.
+            metadata_token = extra_data.pop(PROMPT_METADATA_TOKEN_KEY, None)
+            server_instance.active_prompt_metadata_token = metadata_token
+
             asset_seeder.pause()
-            e.execute(item[2], prompt_id, extra_data, item[4])
+            try:
+                e.execute(item[2], prompt_id, extra_data, item[4])
 
-            need_gc = True
+                need_gc = True
 
-            remove_sensitive = lambda prompt: prompt[:5] + prompt[6:]
-            q.task_done(item_id,
-                        e.history_result,
-                        status=execution.PromptQueue.ExecutionStatus(
-                            status_str='success' if e.success else 'error',
-                            completed=e.success,
-                            messages=e.status_messages), process_item=remove_sensitive)
-            if server_instance.client_id is not None:
-                server_instance.send_sync("executing", {"node": None, "prompt_id": prompt_id}, server_instance.client_id)
+                remove_sensitive = lambda prompt: prompt[:5] + prompt[6:]
+                q.task_done(item_id,
+                            e.history_result,
+                            status=execution.PromptQueue.ExecutionStatus(
+                                status_str='success' if e.success else 'error',
+                                completed=e.success,
+                                messages=e.status_messages), process_item=remove_sensitive)
+                if server_instance.client_id is not None:
+                    server_instance.send_sync("executing", {"node": None, "prompt_id": prompt_id}, server_instance.client_id)
+            finally:
+                # Drop the per-prompt metadata only AFTER the terminal "executing"
+                # send so the registered workflow_id is merged onto that frame.
+                # This is what eliminates the #13684 finally-clear race.
+                server_instance.active_prompt_metadata_token = None
+                server_instance.unregister_prompt_metadata(metadata_token)
 
             current_time = time.perf_counter()
             execution_time = current_time - execution_start_time
diff --git a/server.py b/server.py
index 44470b904..8e55990bb 100644
--- a/server.py
+++ b/server.py
@@ -8,7 +8,15 @@ import time
 import nodes
 import folder_paths
 import execution
+import threading
 from comfy_execution.jobs import JobStatus, get_job, get_all_jobs
+from comfy_execution.metadata import (
+    PROMPT_METADATA_TOKEN_KEY,
+    PromptMetadata,
+    build_prompt_metadata,
+    merge_prompt_metadata,
+    resolve_progress_text_sid,
+)
 import uuid
 import urllib
 import json
@@ -252,6 +260,15 @@ class PromptServer():
         self.last_node_id = None
         self.client_id = None
 
+        # Keyed by an internal monotonic token rather than by ``prompt_id``
+        # because clients can supply the same ``prompt_id`` on retry/dedupe.
+        self.prompt_metadata: dict[int, PromptMetadata] = {}
+        self._prompt_metadata_lock = threading.Lock()
+        self._prompt_metadata_counter = 0
+        # Set by ``main.py``'s queue worker for the duration of one prompt's
+        # execution; read by ``send_sync`` to merge the right metadata.
+        self.active_prompt_metadata_token: Optional[int] = None
+
         self.on_prompt_handlers = []
 
         @routes.get('/ws')
@@ -275,7 +292,12 @@ class PromptServer():
                 await self.send("status", {"status": self.get_queue_info(), "sid": sid}, sid)
                 # On reconnect if we are the currently executing client send the current node
                 if self.client_id == sid and self.last_node_id is not None:
-                    await self.send("executing", { "node": self.last_node_id }, sid)
+                    last_prompt_id = getattr(self, "last_prompt_id", None)
+                    payload: dict = {"node": self.last_node_id}
+                    if last_prompt_id:
+                        payload["prompt_id"] = last_prompt_id
+                        payload.update(self.get_active_prompt_metadata())
+                    await self.send("executing", payload, sid)
 
                 # Flag to track if we've received the first message
                 first_message = True
@@ -955,6 +977,9 @@ class PromptServer():
                         if sensitive_val in extra_data:
                             sensitive[sensitive_val] = extra_data.pop(sensitive_val)
                     extra_data["create_time"] = int(time.time() * 1000)  # timestamp in milliseconds
+                    token = self.register_prompt_metadata(extra_data)
+                    if token is not None:
+                        extra_data[PROMPT_METADATA_TOKEN_KEY] = token
                     self.prompt_queue.put((number, prompt_id, prompt, extra_data, outputs_to_execute, sensitive))
                     response = {"prompt_id": prompt_id, "number": number, "node_errors": valid[3]}
                     return web.json_response(response)
@@ -1216,7 +1241,50 @@ class PromptServer():
         elif sid in self.sockets:
             await send_socket_catch_exception(self.sockets[sid].send_json, message)
 
+    def register_prompt_metadata(self, extra_data: dict) -> Optional[int]:
+        """Capture per-prompt metadata at submission time and return a token
+        identifying this registration.
+
+        Returns ``None`` when there is no recognized metadata, signalling that
+        no token needs to be threaded through the queue. Otherwise the token
+        must be stored on the queue item (typically via
+        :data:`PROMPT_METADATA_TOKEN_KEY` in ``extra_data``) and pinned on the
+        server as ``active_prompt_metadata_token`` while the prompt runs, so
+        the merge in ``send_sync`` picks up this prompt's metadata even when
+        another prompt is registered under the same ``prompt_id``.
+        """
+        meta = build_prompt_metadata(extra_data)
+        if not meta:
+            return None
+        with self._prompt_metadata_lock:
+            self._prompt_metadata_counter += 1
+            token = self._prompt_metadata_counter
+            self.prompt_metadata[token] = meta
+        return token
+
+    def unregister_prompt_metadata(self, token: Optional[int]) -> None:
+        if token is None:
+            return
+        with self._prompt_metadata_lock:
+            self.prompt_metadata.pop(token, None)
+
+    def get_prompt_metadata_by_token(self, token: Optional[int]) -> PromptMetadata:
+        if token is None:
+            return {}
+        with self._prompt_metadata_lock:
+            return dict(self.prompt_metadata.get(token, {}))
+
+    def get_active_prompt_metadata(self) -> PromptMetadata:
+        """Snapshot of the metadata for the currently-executing prompt."""
+        return self.get_prompt_metadata_by_token(self.active_prompt_metadata_token)
+
     def send_sync(self, event, data, sid=None):
+        data = merge_prompt_metadata(
+            self.prompt_metadata,
+            self._prompt_metadata_lock,
+            self.active_prompt_metadata_token,
+            data,
+        )
         self.loop.call_soon_threadsafe(
             self.messages.put_nowait, (event, data, sid))
 
@@ -1285,7 +1353,10 @@ class PromptServer():
         return json_data
 
     def send_progress_text(
-        self, text: Union[bytes, bytearray, str], node_id: str, sid=None
+        self,
+        text: Union[bytes, bytearray, str],
+        node_id: str,
+        sid=None,
     ):
         if isinstance(text, str):
             text = text.encode("utf-8")
@@ -1294,4 +1365,11 @@ class PromptServer():
         # Pack the node_id length as a 4-byte unsigned integer, followed by the node_id bytes
         message = struct.pack(">I", len(node_id_bytes)) + node_id_bytes + text
 
+        # Default routing to the active prompt's client so other clients don't
+        # silently receive untagged text frames. The binary wire format does
+        # not yet carry prompt_id/workflow_id, so cross-tab filtering inside a
+        # single client still depends on a follow-up wire-format change with a
+        # feature flag.
+        sid = resolve_progress_text_sid(sid, self.client_id)
+
         self.send_sync(BinaryEventTypes.TEXT, message, sid)
diff --git a/tests-unit/server_test/test_prompt_metadata.py b/tests-unit/server_test/test_prompt_metadata.py
new file mode 100644
index 000000000..1f9b9dc9b
--- /dev/null
+++ b/tests-unit/server_test/test_prompt_metadata.py
@@ -0,0 +1,182 @@
+"""Tests for the per-prompt metadata registry used to propagate ``workflow_id``
+through WebSocket events without coupling ``execution.py`` to workflow-level
+concepts.
+
+The registry is keyed by an internal monotonic token (NOT by ``prompt_id``)
+because ``post_prompt`` accepts a client-supplied ``prompt_id`` verbatim and
+two prompts can share an id. ``main.py``'s queue worker pins the active token
+on the server around each ``e.execute(...)`` and the merge in ``send_sync``
+reads that pinned token, so each prompt's events get its own metadata
+regardless of ``prompt_id`` collisions or queue-vs-stack ordering.
+"""
+
+import threading
+
+import pytest
+
+from comfy_execution.metadata import (
+    build_prompt_metadata,
+    merge_prompt_metadata,
+    resolve_progress_text_sid,
+)
+
+
+@pytest.fixture
+def registry():
+    return {}
+
+
+@pytest.fixture
+def lock():
+    return threading.Lock()
+
+
+class TestBuildPromptMetadata:
+    def test_returns_workflow_id_when_present(self):
+        extra_data = {"extra_pnginfo": {"workflow": {"id": "wf-1"}}}
+        assert build_prompt_metadata(extra_data) == {"workflow_id": "wf-1"}
+
+    def test_empty_when_workflow_id_missing(self):
+        assert build_prompt_metadata({}) == {}
+        assert build_prompt_metadata({"extra_pnginfo": {}}) == {}
+        assert build_prompt_metadata({"extra_pnginfo": {"workflow": {}}}) == {}
+
+    def test_empty_when_workflow_id_not_a_non_empty_string(self):
+        assert build_prompt_metadata({"extra_pnginfo": {"workflow": {"id": ""}}}) == {}
+        assert build_prompt_metadata({"extra_pnginfo": {"workflow": {"id": 42}}}) == {}
+        assert build_prompt_metadata({"extra_pnginfo": {"workflow": {"id": None}}}) == {}
+
+    def test_empty_on_non_dict_input(self):
+        assert build_prompt_metadata(None) == {}
+        assert build_prompt_metadata("not a dict") == {}
+
+
+class TestMergeMetadata:
+    """``merge_prompt_metadata`` decorates execution events with the metadata
+    for the currently-active token. Event payload fields win on conflict,
+    binary payloads pass through, and the merge is gated on a ``prompt_id``
+    marker to avoid decorating server-status events like ``status`` /
+    ``queue_updated``."""
+
+    def test_merges_for_active_token_when_payload_has_prompt_id(self, registry, lock):
+        registry[42] = {"workflow_id": "wf-1"}
+        merged = merge_prompt_metadata(registry, lock, 42, {"node": "n1", "prompt_id": "p1"})
+        assert merged == {"node": "n1", "prompt_id": "p1", "workflow_id": "wf-1"}
+
+    def test_passthrough_when_no_active_token(self, registry, lock):
+        registry[42] = {"workflow_id": "wf-1"}
+        merged = merge_prompt_metadata(registry, lock, None, {"node": "n1", "prompt_id": "p1"})
+        assert merged == {"node": "n1", "prompt_id": "p1"}
+
+    def test_passthrough_when_active_token_unknown(self, registry, lock):
+        # Token was unregistered already (or never registered) — merge is a no-op.
+        merged = merge_prompt_metadata(registry, lock, 99, {"prompt_id": "p1"})
+        assert merged == {"prompt_id": "p1"}
+
+    def test_passthrough_when_no_prompt_id(self, registry, lock):
+        # Server-status frames (status, queue_updated, etc.) carry no prompt_id
+        # and must not be decorated.
+        registry[42] = {"workflow_id": "wf-1"}
+        merged = merge_prompt_metadata(registry, lock, 42, {"status": {"queue_remaining": 0}})
+        assert merged == {"status": {"queue_remaining": 0}}
+
+    def test_passthrough_for_non_dict_payload(self, registry, lock):
+        registry[42] = {"workflow_id": "wf-1"}
+        binary = (b"image-bytes", {"prompt_id": "p1"})
+        assert merge_prompt_metadata(registry, lock, 42, binary) is binary
+
+    def test_event_payload_wins_over_registered_metadata(self, registry, lock):
+        registry[42] = {"workflow_id": "wf-registered"}
+        merged = merge_prompt_metadata(
+            registry, lock, 42, {"prompt_id": "p1", "workflow_id": "wf-caller"}
+        )
+        assert merged["workflow_id"] == "wf-caller"
+
+
+class TestProgressTextSidResolution:
+    """``BinaryEventTypes.TEXT`` frames don't yet carry ``prompt_id`` /
+    ``workflow_id`` in their wire shape, so cross-client routing has to happen
+    at the ``sid`` level. The default sid pins the broadcast to the active
+    prompt's client.
+    """
+
+    def test_explicit_sid_passes_through(self):
+        assert resolve_progress_text_sid("client-explicit", "client-active") == "client-explicit"
+
+    def test_none_sid_defaults_to_active_client(self):
+        assert resolve_progress_text_sid(None, "client-active") == "client-active"
+
+    def test_none_sid_with_no_active_client_stays_none(self):
+        assert resolve_progress_text_sid(None, None) is None
+
+
+class TestPromptIdCollisionWithTokens:
+    """Two prompts can be queued with the same client-supplied ``prompt_id``.
+    With a registry keyed by ``prompt_id`` the second registration would
+    overwrite the first or be erased by the first's unregister. The token model
+    makes each registration independent."""
+
+    def test_two_submissions_get_distinct_tokens_and_each_merges_correctly(self, registry, lock):
+        # Two submissions of the same prompt_id with different workflow_ids.
+        registry[1] = {"workflow_id": "wf-A"}  # token from submission #1
+        registry[2] = {"workflow_id": "wf-B"}  # token from submission #2
+
+        # Worker is currently running submission #1.
+        merged = merge_prompt_metadata(registry, lock, 1, {"prompt_id": "P", "node": "x"})
+        assert merged["workflow_id"] == "wf-A"
+
+        # Worker switches to submission #2 (queue ordering, retry, whatever).
+        merged = merge_prompt_metadata(registry, lock, 2, {"prompt_id": "P", "node": "y"})
+        assert merged["workflow_id"] == "wf-B"
+
+    def test_unregister_by_token_does_not_drop_concurrent_submission(self, registry, lock):
+        registry[1] = {"workflow_id": "wf-A"}
+        registry[2] = {"workflow_id": "wf-B"}
+
+        # Submission #1 finishes — drop its token only.
+        registry.pop(1, None)
+
+        # Submission #2 still has its metadata.
+        merged = merge_prompt_metadata(registry, lock, 2, {"prompt_id": "P"})
+        assert merged["workflow_id"] == "wf-B"
+
+    def test_execution_order_independent_of_registration_order(self, registry, lock):
+        """Regression for the LIFO-stack failure mode: queue executes #1 first
+        but the previous stack design would have made the merge pick the
+        latest-registered (#2) metadata. Token model is immune."""
+        registry[1] = {"workflow_id": "wf-A"}
+        registry[2] = {"workflow_id": "wf-B"}
+
+        # Even though #2 was registered after #1, executing #1 still sees wf-A.
+        merged_first_running = merge_prompt_metadata(registry, lock, 1, {"prompt_id": "P"})
+        assert merged_first_running["workflow_id"] == "wf-A"
+
+
+class TestRaceRegressionForTerminalExecutingFrame:
+    """Regression for the PR #13684 finally-clear race.
+
+    Executor's ``finally`` previously cleared the workflow_id source, so the
+    post-completion terminal frame shipped ``workflow_id=None``. With the
+    token model, the active token stays pinned until ``main.py`` clears it
+    *after* the terminal send.
+    """
+
+    def test_terminal_executing_frame_includes_workflow_id(self, registry, lock):
+        registry[7] = {"workflow_id": "wf-1"}
+        active_token = 7
+
+        # main.py emits the terminal frame BEFORE clearing the active token.
+        terminal = merge_prompt_metadata(
+            registry, lock, active_token, {"node": None, "prompt_id": "p1"}
+        )
+        # main.py's finally: clear active token + unregister.
+        active_token = None
+        registry.pop(7, None)
+
+        assert terminal == {"node": None, "prompt_id": "p1", "workflow_id": "wf-1"}
+
+        # After cleanup, straggler events get no metadata.
+        straggler = merge_prompt_metadata(
+            registry, lock, active_token, {"node": None, "prompt_id": "p1"}
+        )
+        assert "workflow_id" not in straggler
diff --git a/tests-unit/server_test/test_prompt_metadata_e2e.py b/tests-unit/server_test/test_prompt_metadata_e2e.py
new file mode 100644
index 000000000..c76688ac2
--- /dev/null
+++ b/tests-unit/server_test/test_prompt_metadata_e2e.py
@@ -0,0 +1,163 @@
+"""End-to-end checks of the prompt-metadata propagation.
+
+These tests instantiate the real ``PromptServer`` (no heavy mocking) and drive
+the same call sequence ``main.py`` would: register metadata, pin the token,
+emit a bunch of execution-shaped frames through ``send_sync``, then clear the
+token + unregister. We then drain the server's message queue and inspect the
+exact frames that would have been written to the WebSocket — proving the wire
+shape and the ``prompt_id`` collision invariants without needing a browser.
+"""
+
+import asyncio
+import os
+import sys
+
+import pytest
+
+# Ensure the repo root is the first thing on sys.path so ``utils`` resolves to
+# the ComfyUI package, not a site-packages namespace package. ``utils`` must
+# load before ``app.frontend_management`` imports it.
+REPO_ROOT = os.path.abspath(os.path.join(os.path.dirname(__file__), "..", ".."))
+if REPO_ROOT not in sys.path:
+    sys.path.insert(0, REPO_ROOT)
+import utils  # noqa: F401  -- pin the package before later imports
+
+from comfy_execution.metadata import PROMPT_METADATA_TOKEN_KEY
+
+server_module = pytest.importorskip("server")
+
+
+@pytest.fixture
+def prompt_server():
+    loop = asyncio.new_event_loop()
+    try:
+        server = server_module.PromptServer(loop)
+        yield server
+    finally:
+        loop.close()
+
+
+def _drain(server) -> list:
+    """Empty the server's internal asyncio.Queue and return every (event, data, sid)."""
+    frames = []
+    queue = server.messages
+    while not queue.empty():
+        frames.append(queue.get_nowait())
+    return frames
+
+
+def _run_pending_callbacks(server):
+    """``send_sync`` schedules ``messages.put_nowait`` via ``loop.call_soon_threadsafe``.
+    Pump the loop a single iteration so those callbacks land before we drain."""
+    server.loop.call_soon(server.loop.stop)
+    server.loop.run_forever()
+
+
+def _simulate_prompt_lifecycle(server, extra_data: dict, prompt_id: str):
+    """Replicates what ``main.py``'s queue worker does around ``e.execute(...)``
+    plus a representative sample of the events ``execution.py`` emits."""
+    token = server.register_prompt_metadata(extra_data)
+    if token is not None:
+        extra_data[PROMPT_METADATA_TOKEN_KEY] = token
+
+    # Worker picks up the item, pins the token.
+    server.active_prompt_metadata_token = extra_data.pop(PROMPT_METADATA_TOKEN_KEY, None)
+    client_id = "client-A"
+    server.client_id = client_id
+
+    # A representative sample of the eight execution events listed in PR #13684.
+    server.send_sync("execution_start", {"prompt_id": prompt_id}, client_id)
+    server.send_sync("execution_cached", {"nodes": [], "prompt_id": prompt_id}, client_id)
+    server.send_sync("executing", {"node": "n1", "display_node": "n1", "prompt_id": prompt_id}, client_id)
+    server.send_sync(
+        "executed",
+        {"node": "n1", "display_node": "n1", "output": {}, "prompt_id": prompt_id},
+        client_id,
+    )
+    server.send_sync("execution_success", {"prompt_id": prompt_id}, client_id)
+    # The terminal frame ``main.py`` itself emits, just before clearing state.
+    server.send_sync("executing", {"node": None, "prompt_id": prompt_id}, client_id)
+
+    # Worker finally clause: clear token then unregister.
+    server.active_prompt_metadata_token = None
+    server.unregister_prompt_metadata(token)
+
+
+class TestEndToEndWorkflowIdOnAllExecutionEvents:
+    def test_every_execution_event_carries_workflow_id(self, prompt_server):
+        _simulate_prompt_lifecycle(
+            prompt_server,
+            extra_data={"extra_pnginfo": {"workflow": {"id": "wf-xyz"}}},
+            prompt_id="p-1",
+        )
+        _run_pending_callbacks(prompt_server)
+        frames = _drain(prompt_server)
+
+        assert frames, "no frames emitted"
+        # Every frame with a prompt_id payload must carry workflow_id top-level.
+        for event, data, _sid in frames:
+            if isinstance(data, dict) and data.get("prompt_id"):
+                assert data.get("workflow_id") == "wf-xyz", (event, data)
+
+        # And specifically verify the terminal frame — the #13684 race victim.
+        terminal = [
+            (e, d) for e, d, _ in frames
+            if e == "executing" and isinstance(d, dict) and d.get("node") is None
+        ]
+        assert terminal, "no terminal executing frame emitted"
+        _, terminal_payload = terminal[-1]
+        assert terminal_payload["workflow_id"] == "wf-xyz"
+
+    def test_status_frame_is_not_decorated(self, prompt_server):
+        prompt_server.register_prompt_metadata({"extra_pnginfo": {"workflow": {"id": "wf-1"}}})
+        prompt_server.active_prompt_metadata_token = 1
+
+        # A status frame has no prompt_id and must remain untouched.
+        prompt_server.send_sync("status", {"status": {"queue_remaining": 0}}, None)
+        _run_pending_callbacks(prompt_server)
+        frames = _drain(prompt_server)
+
+        assert any(e == "status" for e, _, _ in frames)
+        for event, data, _ in frames:
+            if event == "status":
+                assert "workflow_id" not in data
+
+
+class TestEndToEndPromptIdCollision:
+    """Drive two prompts with the same client-supplied ``prompt_id`` but
+    different ``workflow_id`` values. The token model must keep their event
+    streams attributed correctly."""
+
+    def test_same_prompt_id_two_workflows_each_stream_attributed_correctly(self, prompt_server):
+        _simulate_prompt_lifecycle(
+            prompt_server,
+            extra_data={"extra_pnginfo": {"workflow": {"id": "wf-A"}}},
+            prompt_id="P-shared",
+        )
+        _simulate_prompt_lifecycle(
+            prompt_server,
+            extra_data={"extra_pnginfo": {"workflow": {"id": "wf-B"}}},
+            prompt_id="P-shared",
+        )
+        _run_pending_callbacks(prompt_server)
+        frames = _drain(prompt_server)
+
+        # Partition the frames by lifecycle (execution_start..terminal-executing).
+        runs: list[list[dict]] = [[]]
+        for event, data, _ in frames:
+            if not isinstance(data, dict):
+                continue
+            runs[-1].append({"event": event, **data})
+            if event == "executing" and data.get("node") is None:
+                runs.append([])
+        # The trailing empty bucket from the final split is fine.
+        runs = [r for r in runs if r]
+        assert len(runs) == 2, runs
+
+        run_a, run_b = runs
+        for entry in run_a:
+            if entry.get("prompt_id"):
+                assert entry.get("workflow_id") == "wf-A", entry
+        for entry in run_b:
+            if entry.get("prompt_id"):
+                assert entry.get("workflow_id") == "wf-B", entry