diff --git a/agent-team/agent_team/dispatcher.py b/agent-team/agent_team/dispatcher.py
index aa78b3a..dc84dcd 100644
--- a/agent-team/agent_team/dispatcher.py
+++ b/agent-team/agent_team/dispatcher.py
@@ -604,21 +604,27 @@ def app_branch_pusher(token_provider: Any, *, _run: Any = None) -> BranchPusher:
         token = token_provider.token()
         # Plain remote — the token is NEVER in the URL/argv/stored origin.
         remote = f"https://github.com/{owner}/{repo}.git"
-        # Auth is injected via http.extraHeader through git's GIT_CONFIG_* env
-        # vars (NOT argv) on the network steps (clone + push). Env is visible
-        # only to the same uid via /proc/<pid>/environ, never via ps argv. The
-        # header key is SCOPED to the github.com host
+        # GitHub's git smart-HTTP transport authenticates an installation token via
+        # BASIC auth (username ``x-access-token``), NOT Bearer — Bearer is the REST
+        # API form and git rejects it ("could not read Username" → exit 128). Encode
+        # ``x-access-token:<token>`` and inject it as an Authorization header through
+        # git's GIT_CONFIG_* env vars (NOT argv) on the network steps (clone + push).
+        # Env is visible only to the same uid via /proc/<pid>/environ, never via ps
+        # argv. The header key is SCOPED to the github.com host
         # (``http.https://github.com/.extraHeader``, the GitHub-Actions checkout
-        # pattern) so git never sends the Authorization header to any other host
-        # it might be redirected to.
+        # pattern) so git never sends the Authorization header to any other host it
+        # might be redirected to.
+        basic = base64.b64encode(f"x-access-token:{token}".encode()).decode("ascii")
         auth_env = {
             "GIT_CONFIG_COUNT": "1",
             "GIT_CONFIG_KEY_0": "http.https://github.com/.extraHeader",
-            "GIT_CONFIG_VALUE_0": f"Authorization: Bearer {token}",
+            "GIT_CONFIG_VALUE_0": f"Authorization: Basic {basic}",
         }
 
         def _scrub(s: str) -> str:
-            return s.replace(token, "***")
+            # Scrub BOTH the raw token and the base64 credential blob (which decodes
+            # to the token) so neither can survive in any surfaced error message.
+            return s.replace(token, "***").replace(basic, "***")
 
         with tempfile.TemporaryDirectory() as tmp:
             tmpdir = Path(tmp)
diff --git a/agent-team/tests/test_dispatcher.py b/agent-team/tests/test_dispatcher.py
index 67df394..ebfb8ba 100644
--- a/agent-team/tests/test_dispatcher.py
+++ b/agent-team/tests/test_dispatcher.py
@@ -374,12 +374,18 @@ def test_app_branch_pusher_keeps_token_out_of_argv_and_uses_plain_remote() -> No
         for arg in call["cmd"]:
             assert "ghs_TESTTOKEN" not in arg
 
-    # Auth rides in GIT_CONFIG_* env on the network steps only (clone + push).
+    # Auth rides in GIT_CONFIG_* env on the network steps only (clone + push), as
+    # BASIC auth (username x-access-token) — git smart-HTTP rejects Bearer.
+    expected_basic = "Authorization: Basic " + base64.b64encode(
+        b"x-access-token:ghs_TESTTOKEN"
+    ).decode("ascii")
     clone_env = recorded[0]["env"]
     assert clone_env["GIT_CONFIG_KEY_0"] == "http.https://github.com/.extraHeader"
-    assert clone_env["GIT_CONFIG_VALUE_0"] == "Authorization: Bearer ghs_TESTTOKEN"
+    assert clone_env["GIT_CONFIG_VALUE_0"] == expected_basic
     push_env = recorded[-1]["env"]
-    assert push_env["GIT_CONFIG_VALUE_0"] == "Authorization: Bearer ghs_TESTTOKEN"
+    assert push_env["GIT_CONFIG_VALUE_0"] == expected_basic
+    # The raw token never appears literally in the auth header (it is base64'd).
+    assert "ghs_TESTTOKEN" not in clone_env["GIT_CONFIG_VALUE_0"]
     # The non-network steps (checkout/apply/commit) carry no auth env.
     for call in recorded[1:4]:
         assert call["env"] is None