diff --git a/constructor/build_outputs.py b/constructor/build_outputs.py
index efacdbe30..39a5c9738 100644
--- a/constructor/build_outputs.py
+++ b/constructor/build_outputs.py
@@ -13,7 +13,8 @@
 
 from conda.base.constants import UNKNOWN_CHANNEL
 from conda.common.url import remove_auth, split_anaconda_token
-from conda.core.prefix_data import PrefixGraph
+from conda.core.prefix_data import PrefixData, PrefixGraph
+from conda.exports import default_prefix
 
 from . import __version__
 from .conda_interface import VersionOrder
@@ -21,6 +22,20 @@
 logger = logging.getLogger(__name__)
 
 
+def get_build_env_records(prefix=None):
+    """Return the package records for the environment building the installer.
+
+    Defaults to the currently active conda environment (`default_prefix`,
+    i.e. the one running constructor) if no prefix is given. Not to be
+    confused with construct.yaml's unrelated `default_prefix` setting,
+    which is the end user's install location.
+    """
+    if prefix is None:
+        prefix = default_prefix
+    # interoperability=True also picks up pip-installed packages, not just conda ones.
+    return list(PrefixData(prefix, interoperability=True).iter_records())
+
+
 def _validate_output(output):
     if isinstance(output, str):
         output = {output: None}
@@ -85,6 +100,8 @@ def _serialize(obj):
         else:
             return repr(obj)
 
+    # Packages installed in the environment running constructor.
+    info["_build_environment_packages"] = get_build_env_records()
     outpath = os.path.join(info["_output_dir"], "info.json")
     with open(outpath, "w") as f:
         json.dump(info, f, indent=2, default=_serialize)
diff --git a/news/1314-build-environment-info b/news/1314-build-environment-info
new file mode 100644
index 000000000..f7cde7c0c
--- /dev/null
+++ b/news/1314-build-environment-info
@@ -0,0 +1,19 @@
+### Enhancements
+
+* Add `_build_environment_packages` to `info.json`, listing the packages (including pip-installed ones) present in the environment used to build the installer. (#1314)
+
+### Bug fixes
+
+* <news item>
+
+### Deprecations
+
+* <news item>
+
+### Docs
+
+* <news item>
+
+### Other
+
+* <news item>
diff --git a/tests/test_conda_interface.py b/tests/test_conda_interface.py
new file mode 100644
index 000000000..943bb066d
--- /dev/null
+++ b/tests/test_conda_interface.py
@@ -0,0 +1,127 @@
+import json
+
+import pytest
+from conda.base.context import context
+from conda.common.path.python import get_python_site_packages_short_path
+from conda.core.prefix_data import PrefixData
+from conda.models.records import PackageRecord, PrefixRecord
+
+from constructor.build_outputs import get_build_env_records
+
+# Match the current platform, since tests run on multiple platforms
+SUBDIR = context.subdir
+
+
+def _make_package_record(name, version="1.2.3", build_number=0):
+    """Make a dummy package record for test fixtures."""
+    return PackageRecord(
+        name=name,
+        version=version,
+        build=str(build_number),
+        build_number=build_number,
+        channel=None,
+        subdir=SUBDIR,
+        fn=f"{name}-{version}-{build_number}.conda",
+    )
+
+
+def _fake_prefix_data(tmp_path, records):
+    """Build a PrefixData whose in-memory records are injected directly,
+    so no conda-meta files are ever written to disk. Approach adapted from
+    conda/conda/testing/helpers.py::_get_solver_base, which patches the
+    same private `__prefix_records` attribute for the same reason."""
+    prefix_data = PrefixData(str(tmp_path))
+    prefix_data._PrefixData__prefix_records = {
+        rec.name: PrefixRecord.from_objects(rec) for rec in records
+    }
+    return prefix_data
+
+
+@pytest.fixture
+def patch_prefix_data(monkeypatch):
+    """Patch constructor.build_outputs.PrefixData so get_build_env_records()
+    returns records we control, without touching disk."""
+
+    def _patch(records):
+        # Replace PrefixData itself with this function, so calling
+        # PrefixData(prefix) returns our fake object instead of reading
+        # real conda-meta files. Reuse the same fake per prefix instead of
+        # building a new one each call.
+        fake_instances = {}
+
+        def _fake_prefix_data_for(prefix, **kwargs):
+            if prefix not in fake_instances:
+                fake_instances[prefix] = _fake_prefix_data(prefix, records)
+            return fake_instances[prefix]
+
+        monkeypatch.setattr("constructor.build_outputs.PrefixData", _fake_prefix_data_for)
+
+    return _patch
+
+
+@pytest.mark.parametrize(
+    "records",
+    [
+        pytest.param([], id="empty-environment"),
+        pytest.param([_make_package_record("numpy")], id="single-package"),
+        pytest.param(
+            [
+                _make_package_record("numpy"),
+                _make_package_record("foobar", version="24.11.0"),
+            ],
+            id="multiple-packages",
+        ),
+    ],
+)
+def test_get_build_env_records_with_explicit_prefix(tmp_path, patch_prefix_data, records):
+    patch_prefix_data(records)
+
+    result = get_build_env_records(prefix=str(tmp_path))
+
+    assert sorted(rec.name for rec in result) == sorted(rec.name for rec in records)
+
+
+def test_get_build_env_records_defaults_to_active_environment(
+    monkeypatch, tmp_path, patch_prefix_data
+):
+    """When prefix is not given, it must fall back to conda.exports.default_prefix
+    (the environment currently running constructor), not construct.yaml's
+    unrelated 'default_prefix' install-location setting."""
+    monkeypatch.setattr("constructor.build_outputs.default_prefix", str(tmp_path))
+    patch_prefix_data([_make_package_record("foobar", version="24.11.0")])
+
+    result = get_build_env_records()
+
+    assert [rec.name for rec in result] == ["foobar"]
+
+
+def test_get_build_env_records_includes_pip_installed_packages(tmp_path):
+    """Verify also pip packages are included among build environment deps."""
+    meta_dir = tmp_path / "conda-meta"
+    meta_dir.mkdir()
+
+    # Mock a conda package and a package installed via pip
+    python_record = PrefixRecord(
+        name="python",
+        version="1.2.3",
+        build="0",
+        build_number=0,
+        channel=None,
+        subdir=SUBDIR,
+        fn="python-1.2.3-0.conda",
+        paths_data={"paths": [], "paths_version": 1},
+        files=[],
+    )
+    (meta_dir / "python-1.2.3-0.json").write_text(json.dumps(python_record.dump()))
+
+    site_packages = tmp_path / get_python_site_packages_short_path("1.2")
+    site_packages.mkdir(parents=True)
+    dist_info = site_packages / "fakepkg-1.0.0.dist-info"
+    dist_info.mkdir()
+    (dist_info / "METADATA").write_text("Metadata-Version: 2.1\nName: fakepkg\nVersion: 1.0.0\n")
+    (dist_info / "INSTALLER").write_text("pip\n")
+    (dist_info / "RECORD").write_text("")
+
+    result = get_build_env_records(prefix=str(tmp_path))
+
+    assert sorted(rec.name for rec in result) == ["fakepkg", "python"]
diff --git a/tests/test_examples.py b/tests/test_examples.py
index 5eb670200..e5826730d 100644
--- a/tests/test_examples.py
+++ b/tests/test_examples.py
@@ -2005,6 +2005,14 @@ def test_output_files(tmp_path, installer_type):
     # Test that info.json contains serialized objects
     info_json = json.loads((root_path / "info.json").read_text())
     assert isinstance(info_json.get("_conda_exe_version"), str)
+    _build_environment_packages = info_json.get("_build_environment_packages")
+    assert isinstance(_build_environment_packages, list), (
+        "Build environment packages is not a list."
+    )
+    assert len(_build_environment_packages) > 0, "Build environment packages is empty."
+    assert isinstance(_build_environment_packages[0], dict), (
+        "Build environment package not serialized."
+    )
     _all_pkg_records = info_json.get("_all_pkg_records")
     assert isinstance(_all_pkg_records, list), "Package record is not a list."
     assert len(_all_pkg_records) > 0, "Package record is empty."