diff --git a/backend/druks/services/base.py b/backend/druks/services/base.py
index 3b61e903..dcd49031 100644
--- a/backend/druks/services/base.py
+++ b/backend/druks/services/base.py
@@ -118,6 +118,11 @@ class Service:
     # identity_scopes join the consent ask.
     identity_endpoint: ClassVar[str] = ""
     identity_scopes: ClassVar[tuple[str, ...]] = ()
+    # The identity fact that names the provider account — "sub" for Google,
+    # "id" for GitHub. When set, a fresh sign-in that matches an existing
+    # connection for the same owner updates that row; a revoked row becomes
+    # live again. When empty, each fresh sign-in creates a new connection.
+    identity_key: ClassVar[str] = ""
 
     def __init_subclass__(cls, **kwargs: Any) -> None:
         super().__init_subclass__(**kwargs)
diff --git a/backend/druks/services/models.py b/backend/druks/services/models.py
index b9d3b5fd..2569e3e6 100644
--- a/backend/druks/services/models.py
+++ b/backend/druks/services/models.py
@@ -115,6 +115,26 @@ def list_for_account(cls, provider: str, account_id: str) -> "list[OauthConnecti
             )
         )
 
+    @classmethod
+    def get_for_identity(
+        cls, provider: str, account_id: str, key: str, value: Any
+    ) -> "OauthConnection | None":
+        # A live match wins; among revoked matches, the latest consent wins.
+        return (
+            db_session()
+            .scalars(
+                select(cls)
+                .where(
+                    cls.provider == provider,
+                    cls.account_id == account_id,
+                    cls.identity[key].astext == str(value),
+                )
+                .order_by(cls.revoked_at.is_(None).desc(), cls.connected_at.desc())
+                .limit(1)
+            )
+            .first()
+        )
+
     @classmethod
     def list_for_provider(
         cls, provider: str, *, include_revoked: bool = False
diff --git a/backend/druks/services/routes.py b/backend/druks/services/routes.py
index 26320f89..3c0405bc 100644
--- a/backend/druks/services/routes.py
+++ b/backend/druks/services/routes.py
@@ -126,15 +126,22 @@ async def oauth_callback(state: str = "", code: str = "", error: str = "") -> Re
         raise HTTPException(status_code=400, detail=f"No OAuth service {provider!r}.")
     granted = tokens.get("scope", "").split() or pending["scopes"]
     identity = await service.get_identity(tokens["access_token"])
-    reconsent = bool(pending["connection_id"])
-    if reconsent:
-        row = OauthConnection.get(pending["connection_id"])
+    connection_id = pending["connection_id"]
+    # Reconsent names an existing row by id; a declared identity key
+    # matches a fresh sign-in to one. Both make a revoked row live again.
+    row = None
+    if connection_id:
+        row = OauthConnection.get(connection_id)
         if not row:
             raise HTTPException(
                 status_code=400, detail="The connection was removed while consent was open."
             )
-        # Reconsent names the row, so it also returns a revoked one to life.
-        # A fresh sign-in never does — it always creates a new connection.
+    elif service.identity_key and (value := identity.get(service.identity_key)):
+        row = OauthConnection.get_for_identity(
+            provider, pending["account_id"], service.identity_key, value
+        )
+    reconsent = bool(row)
+    if row:
         row.reconnect(refresh_token=tokens["refresh_token"], scopes=granted, identity=identity)
         # A token cached before this consent must not serve the new one.
         await OauthClient(provider=provider).evict_access_token(row.id)
diff --git a/backend/tests/test_services.py b/backend/tests/test_services.py
index 98a87acd..a45bd06a 100644
--- a/backend/tests/test_services.py
+++ b/backend/tests/test_services.py
@@ -3,14 +3,17 @@
 import html
 import json
 from types import SimpleNamespace
+from urllib.parse import parse_qsl, urlparse
 
 import httpx
 import pytest
+from druks.accounts.models import Account
 from druks.core.apis.github import GitHubClient, get_github_client
 from druks.core.webhooks.github import GitHubEvents
 from druks.database import db_session
 from druks.services.exceptions import ServiceNotConnectedError
-from druks.services.models import ServiceIdentity
+from druks.services.models import OauthConnection, ServiceIdentity
+from druks.services.oauth import OauthClient
 from druks.testing import make_settings
 from fastapi import HTTPException
 from fastapi.testclient import TestClient
@@ -575,6 +578,7 @@ class Acme(Service):
         token_endpoint = "https://acme.test/token"
         identity_endpoint = "https://acme.test/whoami"
         identity_scopes = ("openid",)
+        identity_key = "sub"
 
         class Settings(BaseModel):
             client_id: str
@@ -604,6 +608,36 @@ def handler(request: httpx.Request) -> httpx.Response:
     return Acme
 
 
+@pytest.fixture
+def keyed_acme(acme, monkeypatch):
+    async def get_identity(service, access_token):
+        assert service is acme
+        assert access_token == "at-1"
+        return {"sub": "account-1", "email": "op@acme.test"}
+
+    monkeypatch.setattr(acme, "get_identity", classmethod(get_identity))
+    return acme
+
+
+@pytest.fixture
+def oauth_events(monkeypatch):
+    events = []
+
+    async def record(name, **kwargs):
+        events.append((name, kwargs))
+
+    monkeypatch.setattr("druks.services.routes.publish", record)
+    return events
+
+
+def _complete_oauth_sign_in(client: TestClient, provider: str = "acme") -> None:
+    consent = client.get(f"/api/oauth/{provider}/connect", follow_redirects=False)
+    state = dict(parse_qsl(urlparse(consent.headers["location"]).query))["state"]
+    response = client.get("/api/oauth/callback", params={"state": state, "code": "c-1"})
+
+    assert response.status_code == 200
+
+
 def test_oauth_connect_redirects_to_consent_with_the_scope_union(
     tmp_path, acme, druks_db, monkeypatch
 ):
@@ -723,6 +757,165 @@ def test_oauth_connect_rejects_an_unknown_reconnect_target(tmp_path, acme, druks
         assert client.get("/api/oauth/acme/connect?connection=zzz").status_code == 404
 
 
+def test_fresh_sign_in_with_matching_identity_resurrects_revoked_connection(
+    tmp_path, keyed_acme, druks_db, oauth_events
+):
+    from druks.testing import configure_app_for_test
+
+    ServiceIdentity.connect(
+        keyed_acme.name, identity={"client_id": "id-1"}, secrets={"client_secret": "sec-1"}
+    )
+    account = Account.get_or_create("op@example.com")
+    connection = OauthConnection.create(
+        provider=keyed_acme.name,
+        account_id=account.id,
+        refresh_token="rt-old",
+        scopes=["profile.read"],
+        identity={"sub": "account-1"},
+    )
+    connection_id = connection.id
+    connection.revoke("user")
+    settings = make_settings(tmp_path, urls={"endpoint": "https://druks.example"})
+
+    with TestClient(configure_app_for_test(settings=settings)) as client:
+        _complete_oauth_sign_in(client, keyed_acme.name)
+
+    db_session().expire_all()
+    resurrected = OauthConnection.get(connection_id)
+    assert resurrected
+    assert not resurrected.revoked_at
+    assert not resurrected.revoked_reason
+    assert resurrected.refresh_token.decrypt() == "rt-1"
+    assert [row.id for row in OauthConnection.list_for_provider(keyed_acme.name)] == [connection_id]
+    assert len(OauthConnection.list_for_provider(keyed_acme.name, include_revoked=True)) == 1
+    assert oauth_events == [
+        (
+            "oauth.connected",
+            {
+                "provider": keyed_acme.name,
+                "connection_id": connection_id,
+                "account_id": account.id,
+                "reconsent": True,
+            },
+        )
+    ]
+
+
+def test_matching_fresh_sign_in_lands_on_live_connection_and_evicts_cached_token(
+    tmp_path, keyed_acme, druks_db, oauth_events, monkeypatch
+):
+    from druks.testing import configure_app_for_test
+
+    ServiceIdentity.connect(
+        keyed_acme.name, identity={"client_id": "id-1"}, secrets={"client_secret": "sec-1"}
+    )
+    account = Account.get_or_create("op@example.com")
+    connection = OauthConnection.create(
+        provider=keyed_acme.name,
+        account_id=account.id,
+        refresh_token="rt-old",
+        scopes=["profile.read"],
+        identity={"sub": "account-1"},
+    )
+    connection_id = connection.id
+    evicted_connection_ids = []
+
+    async def record_eviction(oauth_client, evicted_connection_id):
+        assert oauth_client.provider == keyed_acme.name
+        evicted_connection_ids.append(evicted_connection_id)
+
+    monkeypatch.setattr(OauthClient, "evict_access_token", record_eviction)
+    settings = make_settings(tmp_path, urls={"endpoint": "https://druks.example"})
+
+    with TestClient(configure_app_for_test(settings=settings)) as client:
+        _complete_oauth_sign_in(client, keyed_acme.name)
+
+    db_session().expire_all()
+    reconnected = OauthConnection.get(connection_id)
+    assert reconnected
+    assert reconnected.refresh_token.decrypt() == "rt-1"
+    assert len(OauthConnection.list_for_provider(keyed_acme.name, include_revoked=True)) == 1
+    assert evicted_connection_ids == [connection_id]
+    assert oauth_events[-1][1]["connection_id"] == connection_id
+    assert oauth_events[-1][1]["reconsent"] is True
+
+
+def test_fresh_sign_in_with_live_and_revoked_identity_matches_lands_on_live_connection(
+    tmp_path, keyed_acme, druks_db, oauth_events
+):
+    from druks.testing import configure_app_for_test
+
+    ServiceIdentity.connect(
+        keyed_acme.name, identity={"client_id": "id-1"}, secrets={"client_secret": "sec-1"}
+    )
+    account = Account.get_or_create("op@example.com")
+    live = OauthConnection.create(
+        provider=keyed_acme.name,
+        account_id=account.id,
+        refresh_token="rt-live-old",
+        scopes=["profile.read"],
+        identity={"sub": "account-1"},
+    )
+    live_id = live.id
+    revoked = OauthConnection.create(
+        provider=keyed_acme.name,
+        account_id=account.id,
+        refresh_token="rt-revoked-old",
+        scopes=["profile.read"],
+        identity={"sub": "account-1"},
+    )
+    revoked_id = revoked.id
+    revoked.revoke("user")
+    settings = make_settings(tmp_path, urls={"endpoint": "https://druks.example"})
+
+    with TestClient(configure_app_for_test(settings=settings)) as client:
+        _complete_oauth_sign_in(client, keyed_acme.name)
+
+    db_session().expire_all()
+    reconnected = OauthConnection.get(live_id)
+    still_revoked = OauthConnection.get(revoked_id)
+    assert reconnected
+    assert still_revoked
+    assert reconnected.refresh_token.decrypt() == "rt-1"
+    assert still_revoked.revoked_at
+    assert not still_revoked.refresh_token
+    assert len(OauthConnection.list_for_provider(keyed_acme.name, include_revoked=True)) == 2
+    assert oauth_events[-1][1]["connection_id"] == live_id
+    assert oauth_events[-1][1]["reconsent"] is True
+
+
+def test_fresh_sign_in_without_the_declared_identity_fact_creates_a_new_connection(
+    tmp_path, acme, druks_db, oauth_events
+):
+    from druks.testing import configure_app_for_test
+
+    ServiceIdentity.connect(
+        acme.name, identity={"client_id": "id-1"}, secrets={"client_secret": "sec-1"}
+    )
+    account = Account.get_or_create("op@example.com")
+    revoked = OauthConnection.create(
+        provider=acme.name,
+        account_id=account.id,
+        refresh_token="rt-old",
+        scopes=["profile.read"],
+        identity={"sub": "account-1"},
+    )
+    revoked_id = revoked.id
+    revoked.revoke("user")
+    settings = make_settings(tmp_path, urls={"endpoint": "https://druks.example"})
+
+    with TestClient(configure_app_for_test(settings=settings)) as client:
+        _complete_oauth_sign_in(client, acme.name)
+
+    db_session().expire_all()
+    [created] = OauthConnection.list_for_provider(acme.name)
+    assert created.id != revoked_id
+    assert len(OauthConnection.list_for_provider(acme.name, include_revoked=True)) == 2
+    assert OauthConnection.get(revoked_id).revoked_at
+    assert oauth_events[-1][1]["connection_id"] == created.id
+    assert oauth_events[-1][1]["reconsent"] is False
+
+
 def test_fresh_sign_in_after_revoke_creates_a_new_connection(tmp_path, acme, druks_db, monkeypatch):
     from urllib.parse import parse_qsl, urlparse
 
@@ -755,8 +948,8 @@ def sign_in():
         [first] = OauthConnection.list_for_provider("acme")
         assert client.delete(f"/api/oauth/connections/{first.id}").status_code == 204
 
-        # A fresh sign-in never reuses a row, even for the same provider
-        # account. The revoked row stays behind as history.
+        # The identity facts do not include "sub", so the sign-in cannot
+        # match the existing row. The revoked row stays as history.
         sign_in()
         [live] = OauthConnection.list_for_provider("acme")
         assert live.id != first.id
@@ -795,7 +988,7 @@ async def record(name, **kwargs):
         [connection] = OauthConnection.list_for_provider("acme")
         assert client.delete(f"/api/oauth/connections/{connection.id}").status_code == 204
 
-        # Reconsent names the row, so it is the one way back to life.
+        # Reconsent names the row and makes the revoked consent live again.
         reconnect = client.get(
             f"/api/oauth/acme/connect?connection={connection.id}", follow_redirects=False
         )
diff --git a/docs/writing-an-extension.md b/docs/writing-an-extension.md
index 13ac6e44..058be4c3 100644
--- a/docs/writing-an-extension.md
+++ b/docs/writing-an-extension.md
@@ -781,6 +781,13 @@ account's facts (email, username, name). Druks calls it once at consent and
 shows the facts as the connection's label in Settings. `identity_scopes`
 are the scopes that call needs; they join the consent ask.
 
+Declare `identity_key` when one identity fact names the provider account:
+`"sub"` for Google, `"id"` for GitHub. A fresh sign-in that matches an
+existing connection for the same owner updates that row instead of
+creating a second one. A revoked row that matches becomes live again and
+keeps its id. Without the declaration, each fresh sign-in creates a new
+connection.
+
 Some providers have no such endpoint, or return the facts in a different
 shape. Override `get_identity` for them:
 
@@ -805,6 +812,7 @@ class GoogleOauth(Service):
     extra_authorize_params = {"access_type": "offline", "prompt": "consent"}
     identity_endpoint = "https://openidconnect.googleapis.com/v1/userinfo"
     identity_scopes = ("openid", "email")
+    identity_key = "sub"
 
     class Settings(BaseModel):
         client_id: str = Field(title="Client ID")
@@ -851,11 +859,13 @@ identity. Your rows never need tombstone copies of either.
 Your UI starts a sign-in by opening `/api/oauth/acme/connect` — the
 platform runs the consent with the union of every installed extension's
 declared scopes and stores the connection for the signed-in user. A fresh
-sign-in always creates a new connection, even for a provider account that
-was connected before. To widen an existing connection's scopes, open
+sign-in creates a new connection, unless the service's `identity_key`
+matches it to an existing connection for the same owner. To widen an
+existing connection's scopes, open
 `/api/oauth/acme/connect?connection=<id>`; reconsent replaces its tokens.
-Reconsent names the row, so it also returns a revoked connection to life
-under its old id — the only way a row comes back.
+Reconsent names the row, so it also makes a revoked connection live again
+under its old id. A fresh sign-in that matches the `identity_key` does the
+same.
 Add `?next=/app/night_watch/accounts` to land the user back on your
 page after consent instead of the generic "connected" page. `next`
 must be a bare path starting with `/` — a URL with a scheme or host is
@@ -864,12 +874,13 @@ rejected, so the door can never redirect off the box. Register
 serves every service.
 
 React to sign-ins with the signal machinery. The platform publishes
-`oauth.connected` when a consent completes. `reconsent` is true when it
-replaced an existing connection's tokens, including a revoked row that
-returned to life. It publishes `oauth.disconnected` when a connection is
-revoked — by the user, or because the service's client credentials were
-replaced. Revocation is a state, not a deletion: your subscriber can still
-read the connection it is told about. Subscribe in `subscribers.py`:
+`oauth.connected` when a consent completes. `reconsent` is true when the
+consent replaced an existing connection's tokens. This happens on
+reconsent by id and on an `identity_key` match, for a live or a revoked
+row. It publishes `oauth.disconnected` when a connection is revoked —
+by the user, or because the service's client credentials were replaced.
+Revocation is a state, not a deletion: your subscriber can still read the
+connection it is told about. Subscribe in `subscribers.py`:
 
 ```python
 from druks.signals import subscribe