diff --git a/CHANGELOG.md b/CHANGELOG.md
index bb7107a..95b21f7 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,27 @@
 # Changelog
 
+## Unreleased
+
+**New: account identity for multi-account credential overlays.** One
+`~/.claude` used to imply one account; deva-style runners broke that by
+bind-mounting a different `.credentials.json` per container over the same
+shared config home. The "account-scoped" caches (`usage.cache`,
+`profile.cache`, `usage.jsonl`) then bled across accounts: B rendered A's
+5h/7d bars whenever A fetched last, and the profile stuck to whichever
+account fetched first for 24h. The credentials file itself carries no
+stable identity (tokens rotate), so the runner must say who the session
+is: `STATUSLINE_ACCOUNT` (explicit) or `DEVA_AUTH_TAG` (set by deva from
+`--auth-with`). When present, the user segment shows an `@tag` chip
+(`[MAX|@work]`, tag beats the profile display name — two accounts can
+carry the same human name) and account state moves to
+`accounts/<tag>/` under the shared statusline dir: same-account sessions
+still share one fetch, different accounts stop clobbering each other.
+`auth-default` (single-account) changes nothing; an explicit
+`CLAUDE_DATA_DIR`/`CLAUDE_CACHE_DIR` override is respected verbatim; tags
+are sanitized to a filesystem-safe charset before touching a path. The
+chip also renders for API-key/custom-endpoint sessions, which skip the
+OAuth quota block — exactly the sessions only a tag can tell apart.
+
 ## v0.18.0 — 2026-07-15 — freeze-safe cache expiry deadline, 7d hybrid reset
 
 **Fix: the 7d pressure suffix no longer decays in a frozen frame.** The
diff --git a/README.md b/README.md
index 3ffd880..aa9d404 100644
--- a/README.md
+++ b/README.md
@@ -294,6 +294,8 @@ run. Setting only `CLAUDE_CACHE_DIR` keeps the legacy single-dir behavior.
 | `CLAUDE_7D_WORKDAYS` | unset | Skip weekends in the 7d pace deadline — quota you won't spend Sat/Sun no longer counts against runway (opt-in; the limit itself stays calendar-based) |
 | `CLAUDE_DATA_DIR` | `~/.claude/statusline` | Account-scoped cache + usage log location |
 | `CLAUDE_CACHE_DIR` | `$CLAUDE_DATA_DIR/sessions` | Per-session cache-health state |
+| `STATUSLINE_ACCOUNT` | unset | Account label for multi-account setups: renders an `@label` chip and moves account caches to `accounts/<label>/` so concurrent accounts stop sharing one quota cache |
+| `DEVA_AUTH_TAG` | unset | Same as above, set automatically by [deva](https://github.com/thevibeworks/deva) from `--auth-with` (`auth-file-<stem>` -> `@<stem>`); `auth-default` means single-account and is ignored |
 | `DEBUG_LOG` | `~/.claude/statusline/logs/statusline.log` | Debug log path |
 | `DEBUG_LOG_MAX_BYTES` | `1048576` | Debug log size cap before rotation |
 | `CLAUDE_CODE_MAX_OUTPUT_TOKENS` | `32000` | Output token reserve |
diff --git a/statusline.sh b/statusline.sh
index d767669..37756e4 100755
--- a/statusline.sh
+++ b/statusline.sh
@@ -103,6 +103,34 @@ else
     CLAUDE_ACCOUNT_DIR="$CLAUDE_DATA_DIR"
 fi
 
+# Account scoping. One ~/.claude used to imply one account; credential
+# overlays broke that — deva-style runners bind-mount a different
+# .credentials.json per container over the SAME shared ~/.claude, so the
+# "account-scoped" caches above would bleed across accounts (B renders A's
+# quota whenever A fetched last; profile.cache sticks to the first account
+# for 24h). The credentials file itself has no stable identity (tokens
+# rotate), so the runner must say which account this session is:
+#   STATUSLINE_ACCOUNT  explicit label, wins always
+#   DEVA_AUTH_TAG       from deva >= 0.18 (auth-file-<stem>, api-key-<n>, env);
+#                       auth-default means single-account -> no scoping
+# When set, account state moves to accounts/<tag>/ under the shared dir:
+# same-account sessions still share one fetch, different accounts stop
+# clobbering each other. An explicit CLAUDE_DATA_DIR/CLAUDE_CACHE_DIR
+# override is the caller's layout — respected verbatim, no rescoping.
+ACCOUNT_TAG=""
+if [ -n "${STATUSLINE_ACCOUNT:-}" ]; then
+    ACCOUNT_TAG="$STATUSLINE_ACCOUNT"
+elif [ -n "${DEVA_AUTH_TAG:-}" ] && [ "$DEVA_AUTH_TAG" != "auth-default" ]; then
+    ACCOUNT_TAG="${DEVA_AUTH_TAG#auth-file-}"
+fi
+# Env-derived path component: filesystem-safe charset, bounded length, no
+# dot-leading names (blocks "..", hidden dirs).
+ACCOUNT_TAG=$(printf '%s' "$ACCOUNT_TAG" | tr -cd 'A-Za-z0-9._-' | cut -c1-24)
+case "$ACCOUNT_TAG" in .*) ACCOUNT_TAG="" ;; esac
+if [ -n "$ACCOUNT_TAG" ] && [ -z "$CLAUDE_DATA_DIR_OVERRIDDEN" ]; then
+    CLAUDE_ACCOUNT_DIR="$CLAUDE_ACCOUNT_DIR/accounts/$ACCOUNT_TAG"
+fi
+
 # One-time graceful migration: older versions wrote account-scoped caches
 # and the usage log under $SCRIPT_DIR (and per-session data under
 # $SCRIPT_DIR/sessions). If that legacy layout exists and the new shared
@@ -115,6 +143,9 @@ migrate_legacy_state() {
     # Skip when caller pinned custom dirs or legacy == new (no-op).
     [ -n "${CLAUDE_DATA_DIR_OVERRIDDEN:-}" ] && return 0
     [ "$legacy_data" = "$CLAUDE_ACCOUNT_DIR" ] && return 0
+    # Legacy state predates account scoping and belongs to the default
+    # account — never migrate it into whichever tagged account runs first.
+    [ -n "$ACCOUNT_TAG" ] && return 0
 
     local moved=false
     if [ ! -d "$CLAUDE_ACCOUNT_DIR" ]; then
@@ -2269,13 +2300,22 @@ build_user_info() {
     local tier="$1"
     local name=""
 
-    local profile_cache="${CLAUDE_ACCOUNT_DIR:-$CLAUDE_CACHE_DIR}/profile.cache"
-    if [ -f "$profile_cache" ]; then
-        name=$(jq -r '.account.display_name // empty' "$profile_cache" 2>/dev/null)
-    fi
-
-    if [ "${#name}" -gt 8 ]; then
-        name="${name:0:7}."
+    # Runner-provided account tag beats the profile display name: two
+    # accounts can carry the same human name, the tag (@work / @self)
+    # is what tells concurrent sessions apart. Slightly wider truncation
+    # than names — tags like api-key-1a2b are identity, not prose.
+    if [ -n "${ACCOUNT_TAG:-}" ]; then
+        name="$ACCOUNT_TAG"
+        [ "${#name}" -gt 12 ] && name="${name:0:11}."
+        name="@$name"
+    else
+        local profile_cache="${CLAUDE_ACCOUNT_DIR:-$CLAUDE_CACHE_DIR}/profile.cache"
+        if [ -f "$profile_cache" ]; then
+            name=$(jq -r '.account.display_name // empty' "$profile_cache" 2>/dev/null)
+        fi
+        if [ "${#name}" -gt 8 ]; then
+            name="${name:0:7}."
+        fi
     fi
 
     # Tier is identity, not status — neutral white-weight so it never reads as
@@ -2889,6 +2929,13 @@ if [ -n "$session_id" ] && [ "$_may_have_oauth" = true ]; then
     user_component=$(build_user_info "$user_tier")
 fi
 
+# API-key / custom-endpoint sessions skip the OAuth block above, but an
+# account tag is exactly what tells such sessions apart — chip from the
+# tag alone, no tier.
+if [ -z "$user_component" ] && [ -n "$ACCOUNT_TAG" ]; then
+    user_component=$(build_user_info "")
+fi
+
 right_parts=""
 IFS=',' read -ra order_array <<<"$stat_order"
 for item in "${order_array[@]}"; do
diff --git a/t/helpers.bash b/t/helpers.bash
index 440c4e9..78c4d90 100644
--- a/t/helpers.bash
+++ b/t/helpers.bash
@@ -13,6 +13,11 @@ export STATUSLINE_TESTING
 STATUSLINE_NO_FETCH=1
 export STATUSLINE_NO_FETCH
 
+# Account identity must come from each test, not the host: deva exports
+# DEVA_AUTH_TAG inside its containers, which would otherwise add an account
+# chip (and rescope cache dirs) in every integration run.
+unset DEVA_AUTH_TAG STATUSLINE_ACCOUNT ACCOUNT_TAG
+
 SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
 
 # Color constants (needed by functions)
diff --git a/t/statusline.bats b/t/statusline.bats
index ca35654..bd35ca7 100644
--- a/t/statusline.bats
+++ b/t/statusline.bats
@@ -356,6 +356,37 @@ setup() {
     rm -rf "$tmpdir"
 }
 
+@test "build_user_info: account tag beats profile display name" {
+    tmpdir=$(mktemp -d)
+    CLAUDE_CACHE_DIR="$tmpdir"
+    echo '{"account":{"display_name":"examplename"}}' > "$tmpdir/profile.cache"
+    ACCOUNT_TAG="work"
+    result=$(build_user_info "MAX")
+    plain=$(strip_ansi "$result")
+    [ "$plain" = "[MAX|@work]" ]
+    rm -rf "$tmpdir"
+}
+
+@test "build_user_info: tag-only chip when no tier" {
+    tmpdir=$(mktemp -d)
+    CLAUDE_CACHE_DIR="$tmpdir"
+    ACCOUNT_TAG="work"
+    result=$(build_user_info "")
+    plain=$(strip_ansi "$result")
+    [ "$plain" = "[@work]" ]
+    rm -rf "$tmpdir"
+}
+
+@test "build_user_info: long tag truncated at 12" {
+    tmpdir=$(mktemp -d)
+    CLAUDE_CACHE_DIR="$tmpdir"
+    ACCOUNT_TAG="api-key-1a2b3c4d"
+    result=$(build_user_info "")
+    plain=$(strip_ansi "$result")
+    [ "$plain" = "[@api-key-1a2.]" ]
+    rm -rf "$tmpdir"
+}
+
 # --- format_money_minor currencies ---
 
 @test "format_money_minor: EUR uses euro symbol" {
@@ -2258,3 +2289,78 @@ JSON
         | bash "$SCRIPT_DIR/statusline.sh" --test)
     [[ "$(strip_ansi "$out")" != *'$0'* ]]
 }
+
+# --- account scoping (multi-account credential overlays) --------------------
+
+@test "integration: DEVA_AUTH_TAG renders account chip" {
+    tmpdir=$(mktemp -d)
+    mkdir -p "$tmpdir/.claude"
+    out=$(echo '{"model":{"id":"claude-opus-4-6","display_name":"Opus"},"cwd":"/t","workspace":{"current_dir":"/t"},"version":"2.1.174","cost":{"total_cost_usd":0}}' \
+        | HOME="$tmpdir" DEVA_AUTH_TAG="auth-file-work" bash "$SCRIPT_DIR/statusline.sh" --test)
+    plain=$(strip_ansi "$out")
+    [[ "$plain" == *"[@work]"* ]]
+    rm -rf "$tmpdir"
+}
+
+@test "integration: auth-default tag renders no chip" {
+    tmpdir=$(mktemp -d)
+    mkdir -p "$tmpdir/.claude"
+    out=$(echo '{"model":{"id":"claude-opus-4-6","display_name":"Opus"},"cwd":"/t","workspace":{"current_dir":"/t"},"version":"2.1.174","cost":{"total_cost_usd":0}}' \
+        | HOME="$tmpdir" DEVA_AUTH_TAG="auth-default" bash "$SCRIPT_DIR/statusline.sh" --test)
+    plain=$(strip_ansi "$out")
+    [[ "$plain" != *"@"* ]]
+    rm -rf "$tmpdir"
+}
+
+@test "integration: STATUSLINE_ACCOUNT beats DEVA_AUTH_TAG" {
+    tmpdir=$(mktemp -d)
+    mkdir -p "$tmpdir/.claude"
+    out=$(echo '{"model":{"id":"claude-opus-4-6","display_name":"Opus"},"cwd":"/t","workspace":{"current_dir":"/t"},"version":"2.1.174","cost":{"total_cost_usd":0}}' \
+        | HOME="$tmpdir" STATUSLINE_ACCOUNT="self" DEVA_AUTH_TAG="auth-file-work" bash "$SCRIPT_DIR/statusline.sh" --test)
+    plain=$(strip_ansi "$out")
+    [[ "$plain" == *"[@self]"* ]]
+    [[ "$plain" != *"@work"* ]]
+    rm -rf "$tmpdir"
+}
+
+@test "integration: hostile tag is neutralized, no chip, no scoping" {
+    tmpdir=$(mktemp -d)
+    mkdir -p "$tmpdir/.claude"
+    out=$(echo '{"model":{"id":"claude-opus-4-6","display_name":"Opus"},"cwd":"/t","workspace":{"current_dir":"/t"},"version":"2.1.174","cost":{"total_cost_usd":0}}' \
+        | HOME="$tmpdir" DEVA_AUTH_TAG="../../evil" bash "$SCRIPT_DIR/statusline.sh" --test)
+    plain=$(strip_ansi "$out")
+    [[ "$plain" != *"@"* ]]
+    [ ! -e "$tmpdir/.claude/statusline/accounts" ]
+    rm -rf "$tmpdir"
+}
+
+@test "integration: tagged session reads quota from its scoped cache, not the shared one" {
+    tmpdir=$(mktemp -d)
+    mkdir -p "$tmpdir/.claude/statusline/accounts/work"
+    printf '{"claudeAiOauth":{"accessToken":"tok"}}' > "$tmpdir/.claude/.credentials.json"
+    now=$(date +%s)
+    # Decoy in the legacy shared location: a fresh cache for the OTHER account.
+    printf '{"five_hour":{"utilization":77},"seven_day":{"utilization":77},"fetched_at":%s}' "$now" \
+        > "$tmpdir/.claude/statusline/usage.cache"
+    printf '{"five_hour":{"utilization":42},"seven_day":{"utilization":41},"fetched_at":%s}' "$now" \
+        > "$tmpdir/.claude/statusline/accounts/work/usage.cache"
+    out=$(echo '{"session_id":"acct-test","model":{"id":"claude-opus-4-6","display_name":"Opus"},"cwd":"/t","workspace":{"current_dir":"/t"},"version":"2.1.174","cost":{"total_cost_usd":0}}' \
+        | HOME="$tmpdir" DEVA_AUTH_TAG="auth-file-work" bash "$SCRIPT_DIR/statusline.sh" --test)
+    plain=$(strip_ansi "$out")
+    [[ "$plain" == *"5h[42%]"* ]]
+    [[ "$plain" != *"77%"* ]]
+    rm -rf "$tmpdir"
+}
+
+@test "integration: untagged session still reads the shared cache (back-compat)" {
+    tmpdir=$(mktemp -d)
+    mkdir -p "$tmpdir/.claude/statusline"
+    printf '{"claudeAiOauth":{"accessToken":"tok"}}' > "$tmpdir/.claude/.credentials.json"
+    printf '{"five_hour":{"utilization":33},"seven_day":{"utilization":31},"fetched_at":%s}' "$(date +%s)" \
+        > "$tmpdir/.claude/statusline/usage.cache"
+    out=$(echo '{"session_id":"acct-test2","model":{"id":"claude-opus-4-6","display_name":"Opus"},"cwd":"/t","workspace":{"current_dir":"/t"},"version":"2.1.174","cost":{"total_cost_usd":0}}' \
+        | HOME="$tmpdir" bash "$SCRIPT_DIR/statusline.sh" --test)
+    plain=$(strip_ansi "$out")
+    [[ "$plain" == *"5h[33%]"* ]]
+    rm -rf "$tmpdir"
+}