diff --git a/modules/hook-context-intelligence/amplifier_module_hook_context_intelligence/config_resolver.py b/modules/hook-context-intelligence/amplifier_module_hook_context_intelligence/config_resolver.py
index aa2b6f2..4642935 100644
--- a/modules/hook-context-intelligence/amplifier_module_hook_context_intelligence/config_resolver.py
+++ b/modules/hook-context-intelligence/amplifier_module_hook_context_intelligence/config_resolver.py
@@ -151,13 +151,30 @@ def project_slug(self) -> str:
     def base_path(self) -> Path:
         """Resolved base path for project storage.
 
-        Chain: config['base_path'] → coordinator.config['base_path'] → default.
-        Tilde is expanded.  Result is cached after first access.
+        Resolution order (first truthy value wins):
+        1. ``config['base_path']``  — explicit hook config / settings.yaml override
+        2. ``coordinator.config['base_path']``  — coordinator-level config
+        3. ``AMPLIFIER_CONTEXT_INTELLIGENCE_BASE_PATH`` env var
+        4. default (``~/.amplifier/projects``)
+
+        Mirrors the named-env-var fallback already used by
+        :attr:`context_intelligence_server_url` and
+        :attr:`context_intelligence_api_key` in this resolver — the env var
+        name is fixed and documented, and lets hosts (e.g. amplifier-agent
+        relocating its storage root via ``AMPLIFIER_AGENT_HOME``) point the
+        hook at a host-specific path without changing the vendored
+        ``bundle.md``. No string interpolation of arbitrary ``$VAR``
+        references inside config values — the env var name is the contract.
+
+        Tilde is expanded on the resolved value, regardless of source
+        (config, coordinator, env, or default). Result is cached after
+        first access.
         """
         if self._base_path is None:
             raw = (
                 self._config.get("base_path")
                 or self._coordinator_config_get("base_path")
+                or _env("BASE_PATH")
                 or _DEFAULT_BASE_PATH
             )
             self._base_path = Path(raw).expanduser()
diff --git a/modules/hook-context-intelligence/tests/test_config_resolver.py b/modules/hook-context-intelligence/tests/test_config_resolver.py
index ee9c47c..8dff3d8 100644
--- a/modules/hook-context-intelligence/tests/test_config_resolver.py
+++ b/modules/hook-context-intelligence/tests/test_config_resolver.py
@@ -85,6 +85,67 @@ def test_returns_path_type(self) -> None:
         assert isinstance(resolver.base_path, Path)
 
 
+class TestBasePathEnvFallback:
+    """``AMPLIFIER_CONTEXT_INTELLIGENCE_BASE_PATH`` env-var fallback for ``base_path``.
+
+    Mirrors the named-env-var fallback already used by ``server_url`` and
+    ``api_key`` (``_env("SERVER_URL")``/``_env("API_KEY")``). The env var
+    sits between coordinator config and the hard-coded default in the chain.
+    """
+
+    def test_base_path_falls_back_to_env_var(self, monkeypatch) -> None:
+        """When config and coordinator have no base_path, the env var is used."""
+        monkeypatch.setenv("AMPLIFIER_CONTEXT_INTELLIGENCE_BASE_PATH", "/var/lib/from-env")
+        coordinator = _make_coordinator(config={})
+        resolver = ConfigResolver(config={}, coordinator=coordinator)
+
+        assert resolver.base_path == Path("/var/lib/from-env")
+
+    def test_config_wins_over_env_var(self, monkeypatch) -> None:
+        """Explicit hook config base_path beats the env var (chain priority)."""
+        monkeypatch.setenv("AMPLIFIER_CONTEXT_INTELLIGENCE_BASE_PATH", "/var/lib/from-env")
+        coordinator = _make_coordinator(config={})
+        resolver = ConfigResolver(config={"base_path": "/from-config"}, coordinator=coordinator)
+
+        assert resolver.base_path == Path("/from-config")
+
+    def test_coordinator_config_wins_over_env_var(self, monkeypatch) -> None:
+        """coordinator.config['base_path'] beats the env var (chain priority)."""
+        monkeypatch.setenv("AMPLIFIER_CONTEXT_INTELLIGENCE_BASE_PATH", "/var/lib/from-env")
+        coordinator = _make_coordinator(config={"base_path": "/from-coordinator"})
+        resolver = ConfigResolver(config={}, coordinator=coordinator)
+
+        assert resolver.base_path == Path("/from-coordinator")
+
+    def test_env_var_wins_over_default(self, monkeypatch) -> None:
+        """The env var beats the hard-coded default (chain priority)."""
+        monkeypatch.setenv("AMPLIFIER_CONTEXT_INTELLIGENCE_BASE_PATH", "/var/lib/from-env")
+        coordinator = _make_coordinator(config={})
+        resolver = ConfigResolver(config={}, coordinator=coordinator)
+
+        # Confirms the env-var value is used (not ~/.amplifier/projects).
+        assert resolver.base_path == Path("/var/lib/from-env")
+        assert resolver.base_path != Path("~/.amplifier/projects").expanduser()
+
+    def test_env_var_value_is_tilde_expanded(self, monkeypatch) -> None:
+        """``~`` in the env var value is expanded, same as for other sources."""
+        monkeypatch.setenv("AMPLIFIER_CONTEXT_INTELLIGENCE_BASE_PATH", "~/from-env-tilde")
+        coordinator = _make_coordinator(config={})
+        resolver = ConfigResolver(config={}, coordinator=coordinator)
+
+        assert "~" not in str(resolver.base_path)
+        assert resolver.base_path == Path("~/from-env-tilde").expanduser()
+
+    def test_empty_env_var_treated_as_absent(self, monkeypatch) -> None:
+        """An empty env var falls through to the next source (default)."""
+        monkeypatch.setenv("AMPLIFIER_CONTEXT_INTELLIGENCE_BASE_PATH", "")
+        coordinator = _make_coordinator(config={})
+        resolver = ConfigResolver(config={}, coordinator=coordinator)
+
+        # Empty value is falsy in _env(); chain falls through to default.
+        assert resolver.base_path == Path("~/.amplifier/projects").expanduser()
+
+
 class TestProjectSlugResolution:
     def test_config_value_wins(self) -> None:
         """Explicit hook config project_slug wins over coordinator config."""