diff --git a/.gitignore b/.gitignore
index 6ebfe19..36775dc 100644
--- a/.gitignore
+++ b/.gitignore
@@ -20,3 +20,12 @@ _IGNORE/
 
 # Test failure evidence (US07-04)
 .artifacts/
+
+# Any dotenv, not only the default name.
+*.env
+
+# Local virtualenv for running the app.
+.venv/
+
+# setuptools editable-install metadata.
+*.egg-info/
diff --git a/README.md b/README.md
index 6d97d30..c3564a4 100644
--- a/README.md
+++ b/README.md
@@ -7,16 +7,49 @@ archive workflow. Planning lives in `INTEGRATED_PIPELINE_CONCEPT.md` and
 ## Application (`photo_pipeline`)
 
 The target application lives in `photo_pipeline/` (FastAPI + SQLAlchemy + Alembic).
-Run it with:
+Install it into a virtualenv once:
 
 ```bash
-python -m photo_pipeline migrate   # apply database migrations
-python -m photo_pipeline serve     # start the API + static review UI (127.0.0.1:8000)
+python3.12 -m venv .venv
+.venv/bin/pip install -e ".[vision]"   # drop [vision] for a review-only install
 ```
 
+Then run the two processes:
+
+```bash
+.venv/bin/python -m photo_pipeline migrate   # apply database migrations
+.venv/bin/python -m photo_pipeline serve     # API + review UI at 127.0.0.1:8000/app/
+.venv/bin/python -m photo_pipeline worker    # second terminal: runs the jobs
+```
+
+The server enqueues work and serves the UI; nothing actually scans, scores,
+analyses, uploads, or archives without a worker. `work_item/scripts/python` is the
+*helper's* launcher — it prefers Conda base and falls back to a bare system
+interpreter, so it is not how the application is run.
+
 Configuration comes from `PHOTO_PIPELINE_*` environment variables (see
 `photo_pipeline/config.py`); secrets are referenced, never logged.
 
+### Configuration file
+
+`.env` in the working directory is read at startup, or any path named by
+`PHOTO_PIPELINE_ENV_FILE`. It is parsed, never executed: `KEY=value` lines,
+`#` comments, optional quotes — no interpolation and no `export`. **Anything already
+exported wins**, so the file is the standing configuration and the shell is the
+override for one run.
+
+The archived CLI's variable names still work, so an existing `photo_analyzer.env`
+can be used as-is:
+
+| in the file | applied as |
+|---|---|
+| `LLM_API_KEY` / `GEMINI_API_KEY` | `OPENAI_API_KEY` |
+| `LLM_BASE_URL` | `OPENAI_BASE_URL` |
+| `LIBRARY` | `PHOTO_PIPELINE_LIBRARY_ROOTS` |
+
+`.env` and `*.env` are gitignored and denied by the work-item safety checks: the
+file holds a real key and must never be committed.
+
 ### API access (US07-02)
 
 The app listens on loopback, so its attacker is another page in the same browser.
diff --git a/photo_pipeline/config.py b/photo_pipeline/config.py
index a483c49..6a9dd1b 100644
--- a/photo_pipeline/config.py
+++ b/photo_pipeline/config.py
@@ -18,6 +18,61 @@ from typing import Mapping
 from pydantic import BaseModel, ConfigDict, SecretStr
 
 ENV_PREFIX = "PHOTO_PIPELINE_"
+ENV_FILE_VAR = f"{ENV_PREFIX}ENV_FILE"
+DEFAULT_ENV_FILE = Path(".env")
+
+# The archived CLI's variable names, so the configuration file an operator already
+# has keeps working. The vision provider reads the OpenAI SDK's names, and the
+# library root is configuration here rather than a bare path (US07-01 donor).
+LEGACY_ALIASES = {
+    "LLM_API_KEY": "OPENAI_API_KEY",
+    "GEMINI_API_KEY": "OPENAI_API_KEY",
+    "LLM_BASE_URL": "OPENAI_BASE_URL",
+    "LIBRARY": f"{ENV_PREFIX}LIBRARY_ROOTS",
+}
+
+
+def parse_env_file(text: str) -> dict[str, str]:
+    """``KEY=value`` lines into a mapping. Comments, blanks, and quotes handled.
+
+    Deliberately not a shell: no interpolation, no ``export``, no multi-line values.
+    A configuration file that can run code is a configuration file that can be a
+    vulnerability.
+    """
+    values: dict[str, str] = {}
+    for line in text.splitlines():
+        line = line.strip()
+        if not line or line.startswith("#") or "=" not in line:
+            continue
+        key, _, raw = line.partition("=")
+        key = key.strip()
+        if not key or key.startswith("#"):
+            continue
+        value = raw.strip().strip('"').strip("'")
+        values[key] = value
+        alias = LEGACY_ALIASES.get(key)
+        if alias:
+            values.setdefault(alias, value)
+    return values
+
+
+def load_env_file(path: Path | str | None = None) -> dict[str, str]:
+    """Load ``PHOTO_PIPELINE_ENV_FILE`` (or ``./.env``) into the environment.
+
+    Anything already exported wins: a file is the standing configuration, the shell
+    is what you meant *this time*. Returns what it applied, which is what the CLI
+    prints — names only, never values.
+    """
+    candidate = path or os.environ.get(ENV_FILE_VAR) or DEFAULT_ENV_FILE
+    candidate = Path(candidate)
+    if not candidate.is_file():
+        return {}
+    applied = {}
+    for key, value in parse_env_file(candidate.read_text()).items():
+        if key not in os.environ:
+            os.environ[key] = value
+            applied[key] = value
+    return applied
 
 
 class Config(BaseModel):
@@ -68,6 +123,9 @@ class Config(BaseModel):
     @classmethod
     def from_env(cls, environ: Mapping[str, str] | None = None) -> "Config":
         env = os.environ if environ is None else environ
+        if environ is None:
+            load_env_file()  # a file never overrides what the shell already set
+            env = os.environ
         data: dict = {}
         for name in cls.model_fields:
             raw = env.get(ENV_PREFIX + name.upper())
diff --git a/pyproject.toml b/pyproject.toml
index 6a4900a..8ec5e04 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -8,18 +8,32 @@ dependencies = [
     "sqlalchemy>=2.0",
     "alembic>=1.13",
     "pydantic>=2.7",
-]
-
-[project.optional-dependencies]
-test = [
-    "pytest>=8",
-    "httpx>=0.27",
+    # Imaging is runtime, not test-only: thumbnails decode through Pillow, and the
+    # perceptual hash is a DCT over the decoded pixels (services/hashing.py).
     "pillow>=10",
     "numpy>=1.26",
     "scipy>=1.11",
+]
+
+[project.optional-dependencies]
+# The cloud vision provider. Optional because the analysis stage is the only thing
+# that needs it, and a local review-only install should not pull an API client.
+vision = ["openai>=1.30"]
+test = [
+    "pytest>=8",
+    "httpx>=0.27",
     "playwright>=1.40",
     "pytest-playwright>=0.4",
 ]
+
+[build-system]
+requires = ["setuptools>=68"]
+build-backend = "setuptools.build_meta"
+
+[tool.setuptools]
+# The importable application. ``migrations`` and ``work_item`` live beside it but
+# are not part of the package; without this, an editable install cannot guess.
+packages = ["photo_pipeline"]
 # Browser end-to-end tests also require: python -m playwright install chromium
 
 [tool.ruff]
diff --git a/tests/story_traceability.json b/tests/story_traceability.json
index a36c1c6..658c160 100644
--- a/tests/story_traceability.json
+++ b/tests/story_traceability.json
@@ -15,9 +15,10 @@
       "tests/characterization/test_webapp_query.py"
     ],
     "US01-02": [
-      "tests/unit/test_config.py",
+      "tests/integration/test_app_lifecycle.py",
       "tests/integration/test_migrations.py",
-      "tests/integration/test_app_lifecycle.py"
+      "tests/unit/test_config.py",
+      "tests/unit/test_env_file.py"
     ],
     "US01-03": [
       "tests/unit/test_path_policy.py",
diff --git a/tests/unit/test_env_file.py b/tests/unit/test_env_file.py
new file mode 100644
index 0000000..2657b51
--- /dev/null
+++ b/tests/unit/test_env_file.py
@@ -0,0 +1,69 @@
+"""Configuration from a dotenv file, including the archived CLI's variable names.
+
+An operator who already has a ``photo_analyzer.env`` should not have to rewrite it
+to run the application it was replaced by. The file is standing configuration; the
+shell is what you meant this time, so the shell always wins.
+"""
+
+from __future__ import annotations
+
+import os
+
+from photo_pipeline.config import Config, load_env_file, parse_env_file
+
+SAMPLE = """
+# The archived CLI's shape, comments and all.
+LLM_API_KEY=not-real
+LLM_BASE_URL="https://example.invalid/v1beta/openai/"
+LLM_MODEL='gemini-2.5-flash'
+LIBRARY=/tmp/pictures
+
+MAX_WORKERS=4
+# commented=ignored
+malformed line without an equals sign
+"""
+
+
+def test_the_file_is_parsed_and_never_executed():
+    values = parse_env_file(SAMPLE)
+
+    assert values["LLM_BASE_URL"] == "https://example.invalid/v1beta/openai/"  # quotes stripped
+    assert values["LLM_MODEL"] == "gemini-2.5-flash"
+    assert values["MAX_WORKERS"] == "4"
+    assert "commented" not in values and "malformed line without an equals sign" not in values
+
+
+def test_the_archived_cli_names_still_configure_the_application():
+    values = parse_env_file(SAMPLE)
+
+    assert values["OPENAI_API_KEY"] == "not-real"
+    assert values["OPENAI_BASE_URL"] == "https://example.invalid/v1beta/openai/"
+    assert values["PHOTO_PIPELINE_LIBRARY_ROOTS"] == "/tmp/pictures"
+
+
+def test_an_explicit_shell_variable_beats_the_file(tmp_path, monkeypatch):
+    path = tmp_path / "photo_analyzer.env"
+    path.write_text(SAMPLE)
+    monkeypatch.setenv("OPENAI_API_KEY", "from-the-shell")
+    monkeypatch.delenv("PHOTO_PIPELINE_LIBRARY_ROOTS", raising=False)
+
+    applied = load_env_file(path)
+
+    assert "OPENAI_API_KEY" not in applied, "the file overrode an exported value"
+    assert os.environ["OPENAI_API_KEY"] == "from-the-shell"
+    assert os.environ["PHOTO_PIPELINE_LIBRARY_ROOTS"] == "/tmp/pictures"
+    assert Config.from_env().library_roots[0].name == "pictures"
+
+
+def test_the_file_is_found_through_its_variable(tmp_path, monkeypatch):
+    path = tmp_path / "custom.env"
+    path.write_text("PHOTO_PIPELINE_PORT=9123\n")
+    monkeypatch.delenv("PHOTO_PIPELINE_PORT", raising=False)
+    monkeypatch.setenv("PHOTO_PIPELINE_ENV_FILE", str(path))
+    monkeypatch.chdir(tmp_path)  # no ./.env here, so only the variable can find it
+
+    assert Config.from_env().port == 9123
+
+
+def test_a_missing_file_is_not_an_error(tmp_path):
+    assert load_env_file(tmp_path / "nothing-here.env") == {}