diff --git a/.claude-plugin/marketplace.json b/.claude-plugin/marketplace.json
index a265fe6..f891a3a 100644
--- a/.claude-plugin/marketplace.json
+++ b/.claude-plugin/marketplace.json
@@ -10,7 +10,7 @@
       "name": "warp",
       "description": "Native Warp notifications when Claude completes tasks or needs input",
       "source": "./plugins/warp",
-      "version": "2.0.0",
+      "version": "2.1.0",
       "category": "productivity",
       "tags": ["notifications", "terminal", "warp"]
     }
diff --git a/plugins/warp/.claude-plugin/plugin.json b/plugins/warp/.claude-plugin/plugin.json
index da219bb..8dd9247 100644
--- a/plugins/warp/.claude-plugin/plugin.json
+++ b/plugins/warp/.claude-plugin/plugin.json
@@ -1,7 +1,7 @@
 {
   "name": "warp",
   "description": "Warp terminal integration for Claude Code - native notifications, and more to come",
-  "version": "2.0.0",
+  "version": "2.1.0",
   "author": {
     "name": "Warp",
     "url": "https://warp.dev"
diff --git a/plugins/warp/scripts/emit-terminal-sequence.sh b/plugins/warp/scripts/emit-terminal-sequence.sh
new file mode 100644
index 0000000..b6a83b9
--- /dev/null
+++ b/plugins/warp/scripts/emit-terminal-sequence.sh
@@ -0,0 +1,86 @@
+#!/bin/bash
+# Emits an OSC terminal escape sequence using the best available method.
+#
+# Claude Code 2.1.141 added a `terminalSequence` JSON output field for hooks,
+# so they can deliver OSC sequences without a controlling terminal. Older
+# Claude Code doesn't know that field, and Stop hooks reject unknown fields
+# ("Stop hook error: JSON validation failed"), so on older versions we must
+# write to /dev/tty instead.
+#
+# Decision tree:
+#   1. CLAUDE_CODE_VERSION known, >= 2.1.141 → emit terminalSequence JSON
+#   2. CLAUDE_CODE_VERSION known, <  2.1.141 → write /dev/tty; give up if missing
+#   3. CLAUDE_CODE_VERSION unknown            → try /dev/tty, fall back to JSON
+#
+# Usage:
+#   source "$SCRIPT_DIR/emit-terminal-sequence.sh"
+#   SEQ=$(printf '\033]777;notify;%s;%s\007' "$TITLE" "$BODY")
+#   emit_terminal_sequence "$SEQ"
+#
+# When the sequence is delivered via /dev/tty (side effect), nothing is printed
+# to stdout. When it must go through terminalSequence, a JSON object is printed
+# to stdout — the caller should ensure this reaches the hook's stdout.
+
+# The first Claude Code version that supports the terminalSequence output field.
+TERMINAL_SEQUENCE_MIN_VERSION="2.1.141"
+
+# Compare two dotted version strings (e.g. "2.1.141" >= "2.1.141").
+# Returns 0 (true) if $1 >= $2, 1 (false) otherwise.
+_version_at_least() {
+    local a b av bv i
+    IFS=. read -ra a <<< "$1"
+    IFS=. read -ra b <<< "$2"
+    for ((i = 0; i < ${#b[@]}; i++)); do
+        av="${a[i]:-0}"
+        bv="${b[i]:-0}"
+        if ((av > bv)); then return 0; fi
+        if ((av < bv)); then return 1; fi
+    done
+    return 0
+}
+
+# Extract a bare version number (e.g. "2.1.141") from `claude --version` output,
+# which may look like "claude 2.1.141" or "2.1.141" or "Claude Code v2.1.141".
+_parse_cc_version() {
+    echo "$1" | grep -oE '[0-9]+\.[0-9]+\.[0-9]+' | head -1
+}
+
+# Returns 0 if the running Claude Code version supports terminalSequence.
+_supports_terminal_sequence() {
+    local raw="${CLAUDE_CODE_VERSION:-}"
+    [ -z "$raw" ] && return 1
+    local ver
+    ver=$(_parse_cc_version "$raw")
+    [ -z "$ver" ] && return 1
+    _version_at_least "$ver" "$TERMINAL_SEQUENCE_MIN_VERSION"
+}
+
+emit_terminal_sequence() {
+    local seq="$1"
+    [ -z "$seq" ] && return 0
+
+    # Classify the running Claude Code version, if we can.
+    local raw="${CLAUDE_CODE_VERSION:-}"
+    local ver=""
+    [ -n "$raw" ] && ver=$(_parse_cc_version "$raw")
+
+    if [ -n "$ver" ]; then
+        if _version_at_least "$ver" "$TERMINAL_SEQUENCE_MIN_VERSION"; then
+            # Known new Claude Code — use the structured output field.
+            jq -nc --arg seq "$seq" '{terminalSequence: $seq}'
+        else
+            # Known-old Claude Code — /dev/tty is the only safe path.
+            # Emitting terminalSequence here would be rejected by the Stop
+            # hook validator as an unknown field.
+            printf '%s' "$seq" > /dev/tty 2>/dev/null || true
+        fi
+        return 0
+    fi
+
+    # Unknown Claude Code version — try /dev/tty, fall back to JSON
+    # as a best-effort attempt for new CC without version detection.
+    if printf '%s' "$seq" > /dev/tty 2>/dev/null; then
+        return 0
+    fi
+    jq -nc --arg seq "$seq" '{terminalSequence: $seq}'
+}
diff --git a/plugins/warp/scripts/on-session-start.sh b/plugins/warp/scripts/on-session-start.sh
index ce7364b..50f6963 100755
--- a/plugins/warp/scripts/on-session-start.sh
+++ b/plugins/warp/scripts/on-session-start.sh
@@ -23,6 +23,17 @@ source "$SCRIPT_DIR/build-payload.sh"
 # Read hook input from stdin
 INPUT=$(cat)
 
+# Best-effort Claude Code version detection.
+# Cache in $CLAUDE_ENV_FILE so subsequent hooks can skip the lookup, and
+# export it now so the rest of this hook (warp-notify.sh below) can use it.
+if [ -n "${CLAUDE_ENV_FILE:-}" ] && [ -z "${CLAUDE_CODE_VERSION:-}" ]; then
+    CC_VERSION=$(claude --version 2>/dev/null | head -1 || true)
+    if [ -n "$CC_VERSION" ]; then
+        echo "export CLAUDE_CODE_VERSION=\"$CC_VERSION\"" >> "$CLAUDE_ENV_FILE"
+        export CLAUDE_CODE_VERSION="$CC_VERSION"
+    fi
+fi
+
 # Read plugin version from plugin.json
 PLUGIN_VERSION=$(jq -r '.version // "unknown"' "$SCRIPT_DIR/../.claude-plugin/plugin.json" 2>/dev/null)
 
diff --git a/plugins/warp/scripts/warp-notify.sh b/plugins/warp/scripts/warp-notify.sh
index 523f873..f65559a 100755
--- a/plugins/warp/scripts/warp-notify.sh
+++ b/plugins/warp/scripts/warp-notify.sh
@@ -4,9 +4,15 @@
 #
 # For structured Warp notifications, title should be "warp://cli-agent"
 # and body should be a JSON string matching the cli-agent notification schema.
+#
+# Output behavior:
+#   - On old Claude Code: writes OSC 777 directly to /dev/tty (no stdout)
+#   - On new Claude Code (>= 2.1.141): prints {terminalSequence: ...} JSON to
+#     stdout so the caller can pass it through as hook output
 
 SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
 source "$SCRIPT_DIR/should-use-structured.sh"
+source "$SCRIPT_DIR/emit-terminal-sequence.sh"
 
 # Only emit notifications when we've confirmed the Warp build can render them.
 if ! should_use_structured; then
@@ -17,5 +23,5 @@ TITLE="${1:-Notification}"
 BODY="${2:-}"
 
 # OSC 777 format: \033]777;notify;<title>;<body>\007
-# Write directly to /dev/tty to ensure it reaches the terminal
-printf '\033]777;notify;%s;%s\007' "$TITLE" "$BODY" > /dev/tty 2>/dev/null || true
+SEQ=$(printf '\033]777;notify;%s;%s\007' "$TITLE" "$BODY")
+emit_terminal_sequence "$SEQ"
diff --git a/plugins/warp/tests/test-hooks.sh b/plugins/warp/tests/test-hooks.sh
index c8fcbb6..754bdd0 100755
--- a/plugins/warp/tests/test-hooks.sh
+++ b/plugins/warp/tests/test-hooks.sh
@@ -196,6 +196,70 @@ assert_eq "newer preview version returns true" "0" "$?"
 unset WARP_CLI_AGENT_PROTOCOL_VERSION
 unset WARP_CLIENT_VERSION
 
+echo ""
+echo "=== emit-terminal-sequence.sh ==="
+
+source "$SCRIPT_DIR/../scripts/emit-terminal-sequence.sh"
+
+echo ""
+echo "--- Version comparison ---"
+_version_at_least "2.1.141" "2.1.141"
+assert_eq "equal versions" "0" "$?"
+_version_at_least "2.1.142" "2.1.141"
+assert_eq "newer patch" "0" "$?"
+_version_at_least "2.2.0" "2.1.141"
+assert_eq "newer minor" "0" "$?"
+_version_at_least "3.0.0" "2.1.141"
+assert_eq "newer major" "0" "$?"
+_version_at_least "2.1.140" "2.1.141"
+assert_eq "older patch" "1" "$?"
+_version_at_least "2.0.999" "2.1.141"
+assert_eq "older minor" "1" "$?"
+_version_at_least "1.9.999" "2.1.141"
+assert_eq "older major" "1" "$?"
+
+echo ""
+echo "--- Version parsing ---"
+assert_eq "bare version" "2.1.141" "$(_parse_cc_version '2.1.141')"
+assert_eq "prefixed with name" "2.1.141" "$(_parse_cc_version 'claude 2.1.141')"
+assert_eq "prefixed with v" "2.1.141" "$(_parse_cc_version 'Claude Code v2.1.141')"
+assert_eq "empty string" "" "$(_parse_cc_version '')"
+assert_eq "no version" "" "$(_parse_cc_version 'no version here')"
+
+echo ""
+echo "--- _supports_terminal_sequence ---"
+
+unset CLAUDE_CODE_VERSION
+_supports_terminal_sequence
+assert_eq "unset version → false" "1" "$?"
+
+export CLAUDE_CODE_VERSION="2.1.141"
+_supports_terminal_sequence
+assert_eq "exact min version → true" "0" "$?"
+
+export CLAUDE_CODE_VERSION="claude 2.1.150"
+_supports_terminal_sequence
+assert_eq "newer with prefix → true" "0" "$?"
+
+export CLAUDE_CODE_VERSION="2.1.100"
+_supports_terminal_sequence
+assert_eq "older version → false" "1" "$?"
+
+export CLAUDE_CODE_VERSION="garbage"
+_supports_terminal_sequence
+assert_eq "unparseable version → false" "1" "$?"
+
+unset CLAUDE_CODE_VERSION
+
+echo ""
+echo "--- emit_terminal_sequence output ---"
+
+# With known new version → outputs terminalSequence JSON
+export CLAUDE_CODE_VERSION="2.1.141"
+OUTPUT=$(emit_terminal_sequence "test-seq")
+assert_json_field "new CC outputs terminalSequence" "$OUTPUT" ".terminalSequence" "test-seq"
+unset CLAUDE_CODE_VERSION
+
 # --- Routing tests ---
 # These test the hook scripts as subprocesses to verify routing behavior.
 # We override /dev/tty writes since they'd fail in CI.