diff --git a/CHANGELOG.md b/CHANGELOG.md
index a7cd479..37a0f9d 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,6 +7,15 @@ and versions are tracked in the repo-root `VERSION` file.
 
 ## [Unreleased]
 
+### Changed
+
+- Added an optional `BASE_CLI_PRIMARY_LOG` diagnostic sink. Bash logging keeps
+  terminal verbosity unchanged while persisting the DEBUG-level stream to the
+  shared run primary log.
+- Include the local numeric timezone offset in default structured log
+  timestamps and an explicit `UTC` marker when `LOG_UTC=1`, keeping Bash log
+  formatting aligned with Base's Python CLI logs.
+
 ## [1.3.0] - 2026-07-16
 
 ### Fixed
diff --git a/lib/bash/std/README.md b/lib/bash/std/README.md
index 54f90bc..7bfd77e 100644
--- a/lib/bash/std/README.md
+++ b/lib/bash/std/README.md
@@ -38,6 +38,11 @@ The library improves Bash-based scripting in a few practical ways:
 - **Base wrapper integration**: wrapper flags are recognized once and removed
   before command-specific argument parsing begins.
 
+Log timestamps use the host's local timezone and include its numeric offset by
+default, for example `2026-07-18 13:14:32 -0700`. Setting `LOG_UTC=1` switches
+the timestamp to the explicit `UTC` form. Base's `--utc-wrapper` option sets
+this variable for the complete Bash/Python runtime chain.
+
 The goal is not to hide Bash. The goal is to make scripts fail in ways a user
 or developer can understand.
 
diff --git a/lib/bash/std/lib_std.sh b/lib/bash/std/lib_std.sh
index 39049d5..ef498d3 100644
--- a/lib/bash/std/lib_std.sh
+++ b/lib/bash/std/lib_std.sh
@@ -476,9 +476,9 @@ __log_timestamp__() {
     local result_name="$1"
 
     if [[ "${LOG_UTC:-}" == 1 ]]; then
-        TZ=UTC0 printf -v "$result_name" '%(%Y-%m-%d %H:%M:%S)T' -1
+        TZ=UTC0 printf -v "$result_name" '%(%Y-%m-%d %H:%M:%S)T UTC' -1
     else
-        printf -v "$result_name" '%(%Y-%m-%d %H:%M:%S)T' -1
+        printf -v "$result_name" '%(%Y-%m-%d %H:%M:%S %z)T' -1
     fi
 }
 
@@ -516,13 +516,24 @@ __log_source_location__() {
 #
 __print_log_record__() {
     local color="$1" in_level="$2" source_location="$3"
-    shift 3
-    local message timestamp log_line
+    local terminal_enabled="${4:-1}" persist_enabled="${5:-0}"
+    shift 5
+    local message timestamp log_line primary_log
 
     message="$(__join_message__ "$@")"
     __log_timestamp__ timestamp
     printf -v log_line '%s %-7s %s %s' "$timestamp" "$in_level" "$source_location" "$message"
-    printf '%b%s%b\n' "$color" "$log_line" "$COLOR_OFF" >&2
+    if ((terminal_enabled)); then
+        printf '%b%s%b\n' "$color" "$log_line" "$COLOR_OFF" >&2
+    fi
+    if ((persist_enabled)); then
+        primary_log="${BASE_CLI_PRIMARY_LOG:-}"
+        if [[ -n "$primary_log" ]]; then
+            # The launcher creates the primary log with mode 0600.  Direct
+            # library users may not, so keep the same private default here.
+            (umask 077; printf '%s\n' "$log_line" >>"$primary_log") || :
+        fi
+    fi
 }
 
 #
@@ -603,6 +614,7 @@ __print_log__() {
     [[ -n "$in_level" ]] || return 1
     shift
     local logger=default log_level_set log_level color source_location
+    local terminal_enabled persist_enabled
     if [[ "${1-}" == "-l" ]]; then
         if [[ -z "${2-}" ]]; then
             printf '%(%Y-%m-%d %H:%M:%S)T %s\n' -1 "WARN ${BASH_SOURCE[1]}:${BASH_LINENO[0]} Option '-l' needs an argument" >&2
@@ -614,7 +626,12 @@ __print_log__() {
     log_level="${_log_levels[$in_level]}"
     log_level_set="${_loggers_level_map[$logger]:-3}"
 
-    if ((log_level_set >= log_level)); then
+    terminal_enabled=0
+    ((log_level_set >= log_level)) && terminal_enabled=1
+    persist_enabled=0
+    [[ -n "${BASE_CLI_PRIMARY_LOG:-}" ]] && ((log_level <= _log_levels[DEBUG])) && persist_enabled=1
+
+    if ((terminal_enabled || persist_enabled)); then
         # Select color based on log level
         case "$in_level" in
             FATAL|ERROR) color="$COLOR_RED";;
@@ -625,7 +642,7 @@ __print_log__() {
         esac
 
         __log_source_location__ source_location "${BASH_SOURCE[2]:-}" "${BASH_LINENO[1]:-0}"
-        __print_log_record__ "$color" "$in_level" "$source_location" "$@"
+        __print_log_record__ "$color" "$in_level" "$source_location" "$terminal_enabled" "$persist_enabled" "$@"
     fi
 }
 
@@ -658,7 +675,7 @@ __print_log_file__()   {
     else
         local source_location
         __log_source_location__ source_location "${BASH_SOURCE[2]:-}" "${BASH_LINENO[1]:-0}"
-        __print_log_record__ "$COLOR_YELLOW" WARN "$source_location" "Unknown logger '$logger'"
+        __print_log_record__ "$COLOR_YELLOW" WARN "$source_location" 1 1 "Unknown logger '$logger'"
     fi
 }
 
diff --git a/lib/bash/std/tests/lib_std.bats b/lib/bash/std/tests/lib_std.bats
index 4c786e0..6d29694 100644
--- a/lib/bash/std/tests/lib_std.bats
+++ b/lib/bash/std/tests/lib_std.bats
@@ -629,13 +629,26 @@ EOF
     [[ "$(cat "$stderr_file")" == *"VERBOSE"* ]]
 }
 
+@test "log wrappers persist the DEBUG diagnostic stream without changing terminal verbosity" {
+    local stderr_file="$TEST_TMPDIR/log-primary.err"
+    local primary_log="$TEST_TMPDIR/primary.log"
+
+    BASE_CLI_PRIMARY_LOG="$primary_log" log_debug "persisted debug" 2>"$stderr_file"
+    [ ! -s "$stderr_file" ]
+    [[ "$(cat "$primary_log")" == *"DEBUG"*"persisted debug"* ]]
+
+    BASE_CLI_PRIMARY_LOG="$primary_log" log_info "terminal info" 2>>"$stderr_file"
+    [[ "$(cat "$stderr_file")" == *"INFO"*"terminal info"* ]]
+    [[ "$(cat "$primary_log")" == *"INFO"*"terminal info"* ]]
+}
+
 @test "__print_log__ uses local timestamps by default" {
     local stderr_file="$TEST_TMPDIR/log-local-time.err"
     local expected_before expected_after output
 
-    expected_before="$(TZ=Pacific/Honolulu printf '%(%Y-%m-%d %H)T' -1)"
+    expected_before="$(TZ=Pacific/Honolulu printf '%(%Y-%m-%d %H:%M:%S %z)T' -1)"
     TZ=Pacific/Honolulu log_info "local timestamp" 2>"$stderr_file"
-    expected_after="$(TZ=Pacific/Honolulu printf '%(%Y-%m-%d %H)T' -1)"
+    expected_after="$(TZ=Pacific/Honolulu printf '%(%Y-%m-%d %H:%M:%S %z)T' -1)"
     output="$(cat "$stderr_file")"
 
     [[ "$output" == "$expected_before"* || "$output" == "$expected_after"* ]]
@@ -646,11 +659,11 @@ EOF
     local stderr_file="$TEST_TMPDIR/log-utc-time.err"
     local expected_before expected_after output local_before local_after
 
-    expected_before="$(TZ=UTC printf '%(%Y-%m-%d %H)T' -1)"
-    local_before="$(TZ=Pacific/Honolulu printf '%(%Y-%m-%d %H)T' -1)"
+    expected_before="$(TZ=UTC printf '%(%Y-%m-%d %H:%M:%S)T UTC' -1)"
+    local_before="$(TZ=Pacific/Honolulu printf '%(%Y-%m-%d %H:%M:%S %z)T' -1)"
     TZ=Pacific/Honolulu LOG_UTC=1 log_info "utc timestamp" 2>"$stderr_file"
-    expected_after="$(TZ=UTC printf '%(%Y-%m-%d %H)T' -1)"
-    local_after="$(TZ=Pacific/Honolulu printf '%(%Y-%m-%d %H)T' -1)"
+    expected_after="$(TZ=UTC printf '%(%Y-%m-%d %H:%M:%S)T UTC' -1)"
+    local_after="$(TZ=Pacific/Honolulu printf '%(%Y-%m-%d %H:%M:%S %z)T' -1)"
     output="$(cat "$stderr_file")"
 
     [[ "$expected_before" != "$local_before" || "$expected_after" != "$local_after" ]]