diff --git a/bin/base-wrapper b/bin/base-wrapper
index 5c7c9df5..af6ec0c7 100755
--- a/bin/base-wrapper
+++ b/bin/base-wrapper
@@ -45,6 +45,8 @@ Usage:
 
 Options:
   --project <name>  Run using ~/.base.d/<name>/.venv.
+  --preserve-project-context
+                    Keep the inherited BASE_PROJECT while selecting a venv.
   -h, --help        Show this help text.
 
 Purpose:
@@ -61,6 +63,7 @@ EOF
 
 main() {
     local base_cli_path base_cli_source base_home project package python_bin old_pythonpath base_pythonpath
+    local preserve_project_context=0
 
     base_home="$(base_wrapper_base_home)" || base_wrapper_die "Unable to resolve Base home."
     project="${BASE_PROJECT:-base}"
@@ -78,6 +81,9 @@ main() {
                 [[ -n "${1:-}" ]] || base_wrapper_die "Option '--project' requires an argument."
                 project="$1"
                 ;;
+            --preserve-project-context)
+                preserve_project_context=1
+                ;;
             --)
                 shift
                 break
@@ -111,7 +117,9 @@ main() {
     esac
 
     BASE_HOME="$base_home"
-    BASE_PROJECT="$project"
+    if [[ "$preserve_project_context" != 1 || -z "${BASE_PROJECT:-}" ]]; then
+        BASE_PROJECT="$project"
+    fi
     # This wrapper always launches Base's control-plane Python packages. The
     # selected project only chooses the virtual environment; it must not move
     # Base-owned runtime artifacts into a project's namespace.
diff --git a/cli/bash/commands/basectl/tests/command_protocol_fixtures.bash b/cli/bash/commands/basectl/tests/command_protocol_fixtures.bash
index bd836e78..175f15d2 100644
--- a/cli/bash/commands/basectl/tests/command_protocol_fixtures.bash
+++ b/cli/bash/commands/basectl/tests/command_protocol_fixtures.bash
@@ -3,7 +3,8 @@
 # Fake Python executables are Bash scripts loaded through BASH_ENV. Normalize
 # interpreter isolation and the owned entrypoint into the module arguments
 # those stubs model. Real Python integration tests exercise the actual launcher.
-if [[ "${0##*/}" == python* && "${1:-}" == -I ]]; then
+if [[ "${BASE_TEST_PRESERVE_PYTHON_ENTRYPOINT:-}" != 1 &&
+    "${0##*/}" == python* && "${1:-}" == -I ]]; then
     shift
     if [[ "${1:-}" == */base_cli_adapters/module_entrypoint.py ]]; then
         shift
diff --git a/cli/bash/commands/basectl/tests/runtime-dispatch.bats b/cli/bash/commands/basectl/tests/runtime-dispatch.bats
index 53f16999..c8c8f37f 100644
--- a/cli/bash/commands/basectl/tests/runtime-dispatch.bats
+++ b/cli/bash/commands/basectl/tests/runtime-dispatch.bats
@@ -843,6 +843,29 @@ EOF
     [[ "$output" == *"ARGS=-m base_setup --dry-run demo"* ]]
 }
 
+@test "base-wrapper can select the Base venv without replacing active project context" {
+    local python_bin="$TEST_HOME/.base.d/base/.venv/bin/python"
+
+    mkdir -p "$(dirname "$python_bin")"
+    cat > "$python_bin" <<'EOF'
+#!/usr/bin/env bash
+printf 'BASE_PROJECT=%s\n' "$BASE_PROJECT"
+printf 'ARGS=%s\n' "$*"
+EOF
+    chmod +x "$python_bin"
+
+    run env \
+        HOME="$TEST_HOME" \
+        BASE_PROJECT=demo \
+        BASE_TEST_PRESERVE_PYTHON_ENTRYPOINT=1 \
+        "$BASE_REPO_ROOT/bin/base-wrapper" --project base --preserve-project-context \
+        base_projects activation-sources demo --format command-protocol
+
+    [ "$status" -eq 0 ]
+    [[ "$output" == *"BASE_PROJECT=demo"* ]]
+    [[ "$output" == *"ARGS=-I $BASE_REPO_ROOT/cli/python/base_cli_adapters/module_entrypoint.py base_projects activation-sources demo --format command-protocol"* ]]
+}
+
 @test "basectl propagates supported wrapper diagnostics to explicit Base scripts" {
     local script_path="$TEST_TMPDIR/wrapper-diagnostics-script"
 
diff --git a/cli/bash/commands/basectl/tests/runtime-shell.bats b/cli/bash/commands/basectl/tests/runtime-shell.bats
index e5097f07..31a3c374 100644
--- a/cli/bash/commands/basectl/tests/runtime-shell.bats
+++ b/cli/bash/commands/basectl/tests/runtime-shell.bats
@@ -94,7 +94,9 @@ EOF
 #!/usr/bin/env bash
 # Bash 3 reads BASH_ENV before assigning script arguments.
 source "${BASH_ENV:?}"
-if [[ "${1:-}" == "-m" && "${2:-}" == "base_projects" && "${3:-}" == "activation-sources" && "${4:-}" == "demo" ]]; then
+if [[ "${1:-}" == "-I" &&
+    "${2:-}" == "$BASE_HOME/cli/python/base_cli_adapters/module_entrypoint.py" &&
+    "${3:-}" == "base_projects" && "${4:-}" == "activation-sources" && "${5:-}" == "demo" ]]; then
     base_test_protocol_begin activation-source 0
     base_test_protocol_end
     exit 0
@@ -103,6 +105,8 @@ printf 'unexpected base_projects args: %s\n' "$*" >&2
 exit 1
 EOF
     chmod +x "$venv_dir/bin/python"
+    mkdir -p "$TEST_HOME/.base.d/base/.venv/bin"
+    cp "$venv_dir/bin/python" "$TEST_HOME/.base.d/base/.venv/bin/python"
 
     run env \
         HOME="$TEST_HOME" \
@@ -111,6 +115,7 @@ EOF
         BASE_PROJECT_ROOT="$project_root" \
         BASE_PROJECT_MANIFEST="$project_root/base_manifest.yaml" \
         BASE_PROJECT_VENV_DIR="$venv_dir" \
+        BASE_TEST_PRESERVE_PYTHON_ENTRYPOINT=1 \
         PATH="/usr/bin:/bin:/usr/sbin:/sbin" \
         "$BASH" --rcfile "$BASE_REPO_ROOT/lib/bash/runtime/bashrc" -i -c '\
             declare -p BASE_PROJECT; \
@@ -139,7 +144,9 @@ EOF
 #!/usr/bin/env bash
 # Bash 3 reads BASH_ENV before assigning script arguments.
 source "${BASH_ENV:?}"
-if [[ "${1:-}" == "-m" && "${2:-}" == "base_projects" && "${3:-}" == "activation-sources" && "${4:-}" == "demo" ]]; then
+if [[ "${1:-}" == "-I" &&
+    "${2:-}" == "$BASE_HOME/cli/python/base_cli_adapters/module_entrypoint.py" &&
+    "${3:-}" == "base_projects" && "${4:-}" == "activation-sources" && "${5:-}" == "demo" ]]; then
     base_test_protocol_begin activation-source 1
     base_test_protocol_activation_source_record 0 "${BASE_TEST_ACTIVATION_SOURCE:?}"
     base_test_protocol_end
@@ -156,6 +163,8 @@ project_activation_function() {
 }
 EOF
     chmod +x "$venv_dir/bin/python"
+    mkdir -p "$TEST_HOME/.base.d/base/.venv/bin"
+    cp "$venv_dir/bin/python" "$TEST_HOME/.base.d/base/.venv/bin/python"
 
     run env \
         HOME="$TEST_HOME" \
@@ -165,6 +174,7 @@ EOF
         BASE_PROJECT_MANIFEST="$project_root/base_manifest.yaml" \
         BASE_PROJECT_VENV_DIR="$venv_dir" \
         BASE_TEST_ACTIVATION_SOURCE="$activation_script" \
+        BASE_TEST_PRESERVE_PYTHON_ENTRYPOINT=1 \
         PATH="/usr/bin:/bin:/usr/sbin:/sbin" \
         "$BASH" --rcfile "$BASE_REPO_ROOT/lib/bash/runtime/bashrc" -i -c '\
             printf "PROJECT_ACTIVATION_PROJECT=%s\n" "${PROJECT_ACTIVATION_PROJECT:-}"; \
@@ -197,7 +207,9 @@ EOF
 #!/usr/bin/env bash
 # Bash 3 reads BASH_ENV before assigning script arguments.
 source "${BASH_ENV:?}"
-if [[ "${1:-}" == "-m" && "${2:-}" == "base_projects" && "${3:-}" == "activation-sources" && "${4:-}" == "demo" ]]; then
+if [[ "${1:-}" == "-I" &&
+    "${2:-}" == "$BASE_HOME/cli/python/base_cli_adapters/module_entrypoint.py" &&
+    "${3:-}" == "base_projects" && "${4:-}" == "activation-sources" && "${5:-}" == "demo" ]]; then
     printf 'startup-run-root=%s\n' "${BASE_CLI_RUN_ROOT:-unset}" >&2
     printf 'startup-primary-log=%s\n' "${BASE_BASH_LIBS_PRIMARY_LOG:-unset}" >&2
     printf 'startup-history-scope=%s\n' "${BASE_CLI_HISTORY_SCOPE:-unset}" >&2
@@ -205,12 +217,20 @@ if [[ "${1:-}" == "-m" && "${2:-}" == "base_projects" && "${3:-}" == "activation
     base_test_protocol_end
     exit 0
 fi
-if [[ "${1:-}" == "-m" && "${2:-}" == "base_projects" && "${3:-}" == "list" ]]; then
+if [[ ("${1:-}" == "-m" && "${2:-}" == "base_projects" && "${3:-}" == "list") ||
+    ("${1:-}" == "-I" && "${2:-}" == "$BASE_HOME/cli/python/base_cli_adapters/module_entrypoint.py" &&
+    "${3:-}" == "base_projects" && "${4:-}" == "list") ]]; then
     printf 'demo\t%s/demo\n' "${BASE_TEST_WORKSPACE:?}"
     exit 0
 fi
-if [[ "${1:-}" == "-m" && "${2:-}" == "base_history.record" ]]; then
-    printf '%s\n' "$*" >> "${BASE_TEST_RUNTIME_HISTORY_STATE:?}"
+if [[ ("${1:-}" == "-m" && "${2:-}" == "base_history.record") ||
+    ("${1:-}" == "-I" && "${2:-}" == "$BASE_HOME/cli/python/base_cli_adapters/module_entrypoint.py" &&
+    "${3:-}" == "base_history.record") ]]; then
+    if [[ "${1:-}" == "-I" ]]; then
+        printf '%s\n' "-m ${*:3}" >> "${BASE_TEST_RUNTIME_HISTORY_STATE:?}"
+    else
+        printf '%s\n' "$*" >> "${BASE_TEST_RUNTIME_HISTORY_STATE:?}"
+    fi
     exit 0
 fi
 printf 'unexpected base_projects args: %s\n' "$*" >&2
@@ -245,6 +265,7 @@ EOF
         BASE_CLI_PROJECT_NAME=demo \
         BASE_CLI_PROJECT_ROOT="$project_root" \
         BASE_CLI_PROJECT_MANIFEST="$project_root/base_manifest.yaml" \
+        BASE_TEST_PRESERVE_PYTHON_ENTRYPOINT=1 \
         PATH="/usr/bin:/bin:/usr/sbin:/sbin" \
         "$BASH" --rcfile "$BASE_REPO_ROOT/lib/bash/runtime/bashrc" -i -c '\
             for variable in \
@@ -338,7 +359,9 @@ EOF
 #!/usr/bin/env bash
 # Bash 3 reads BASH_ENV before assigning script arguments.
 source "${BASH_ENV:?}"
-if [[ "${1:-}" == "-m" && "${2:-}" == "base_projects" && "${3:-}" == "activation-sources" && "${4:-}" == "demo" ]]; then
+if [[ "${1:-}" == "-I" &&
+    "${2:-}" == "$BASE_HOME/cli/python/base_cli_adapters/module_entrypoint.py" &&
+    "${3:-}" == "base_projects" && "${4:-}" == "activation-sources" && "${5:-}" == "demo" ]]; then
     printf 'ERROR: %s: activate.source[1] script %q does not exist.\n' "$BASE_PROJECT_MANIFEST" ".base/missing.sh" >&2
     exit 1
 fi
@@ -346,6 +369,8 @@ printf 'unexpected base_projects args: %s\n' "$*" >&2
 exit 1
 EOF
     chmod +x "$venv_dir/bin/python"
+    mkdir -p "$TEST_HOME/.base.d/base/.venv/bin"
+    cp "$venv_dir/bin/python" "$TEST_HOME/.base.d/base/.venv/bin/python"
 
     run env \
         HOME="$TEST_HOME" \
@@ -354,6 +379,7 @@ EOF
         BASE_PROJECT_ROOT="$project_root" \
         BASE_PROJECT_MANIFEST="$project_root/base_manifest.yaml" \
         BASE_PROJECT_VENV_DIR="$venv_dir" \
+        BASE_TEST_PRESERVE_PYTHON_ENTRYPOINT=1 \
         BASE_CLI_RUNTIME_OWNER=base \
         BASE_CLI_RUN_ID=failed-activation-run-id \
         BASE_CLI_RUN_ROOT="$activation_run_root" \
@@ -376,6 +402,51 @@ EOF
     [[ "$output" == *"body-history-scope=unset"* ]]
 }
 
+@test "Base runtime shell resolves activation sources with the Base virtual environment" {
+    local project_root="$TEST_TMPDIR/demo"
+    local project_venv_dir="$TEST_TMPDIR/demo-venv"
+    local base_venv_dir="$TEST_HOME/.base.d/base/.venv"
+
+    mkdir -p "$project_root" "$project_venv_dir/bin" "$base_venv_dir/bin"
+    touch "$project_root/base_manifest.yaml"
+    cat > "$project_venv_dir/bin/activate" <<'EOF'
+VIRTUAL_ENV="$BASE_PROJECT_VENV_DIR"
+export VIRTUAL_ENV
+EOF
+    cat > "$project_venv_dir/bin/python" <<'EOF'
+#!/usr/bin/env bash
+printf 'project virtual environment Python was used unexpectedly\n' >&2
+exit 1
+EOF
+    cat > "$base_venv_dir/bin/python" <<'EOF'
+#!/usr/bin/env bash
+source "${BASH_ENV:?}"
+if [[ "${3:-}" == "base_projects" && "${4:-}" == "activation-sources" && "${5:-}" == "demo" ]]; then
+    base_test_protocol_begin activation-source 0
+    base_test_protocol_end
+    exit 0
+fi
+printf 'unexpected Base Python args: %s\n' "$*" >&2
+exit 1
+EOF
+    chmod +x "$project_venv_dir/bin/python" "$base_venv_dir/bin/python"
+
+    run env \
+        HOME="$TEST_HOME" \
+        BASE_HOME="$BASE_REPO_ROOT" \
+        BASE_PROJECT=demo \
+        BASE_PROJECT_ROOT="$project_root" \
+        BASE_PROJECT_MANIFEST="$project_root/base_manifest.yaml" \
+        BASE_PROJECT_VENV_DIR="$project_venv_dir" \
+        PATH="/usr/bin:/bin:/usr/sbin:/sbin" \
+        "$BASH" --rcfile "$BASE_REPO_ROOT/lib/bash/runtime/bashrc" -i -c '\
+            printf "VIRTUAL_ENV=%s\n" "$VIRTUAL_ENV"'
+
+    [ "$status" -eq 0 ]
+    [[ "$output" == *"VIRTUAL_ENV=$project_venv_dir"* ]]
+    [[ "$output" != *"project virtual environment Python was used unexpectedly"* ]]
+}
+
 @test "Base runtime shell loads base_init before user bashrc and owns final prompt" {
     cat > "$TEST_HOME/.bashrc" <<'EOF'
 alias user_bashrc_alias='printf user-bashrc'
diff --git a/lib/bash/runtime/bashrc b/lib/bash/runtime/bashrc
index bb62ad75..790a05d5 100644
--- a/lib/bash/runtime/bashrc
+++ b/lib/bash/runtime/bashrc
@@ -115,7 +115,7 @@ _base_runtime_source_project_activation_scripts() {
         return 1
     }
 
-    scripts_output="$("$wrapper" base_projects activation-sources "$BASE_PROJECT" --format command-protocol)" || {
+    scripts_output="$("$wrapper" --project base --preserve-project-context base_projects activation-sources "$BASE_PROJECT" --format command-protocol)" || {
         _base_runtime_error "Unable to resolve project activation scripts for '$BASE_PROJECT'."
         return 1
     }