diff --git a/apps/desktop/src/app/session/hooks/use-message-stream/gateway-event.ts b/apps/desktop/src/app/session/hooks/use-message-stream/gateway-event.ts
index f36d74ad73e..f057bca4f24 100644
--- a/apps/desktop/src/app/session/hooks/use-message-stream/gateway-event.ts
+++ b/apps/desktop/src/app/session/hooks/use-message-stream/gateway-event.ts
@@ -39,6 +39,7 @@ import {
 import { clearSessionSubagents, pruneDelegateFallbackSubagents, upsertSubagent } from '@/store/subagents'
 import { clearActiveSessionTodos } from '@/store/todos'
 import { recordToolDiff } from '@/store/tool-diffs'
+import { reportInstallMethodWarning } from '@/store/updates'
 import { notifyWorkspaceChanged, toolMayMutateFiles } from '@/store/workspace-events'
 import type { RpcEvent } from '@/types/hermes'
 
@@ -216,6 +217,10 @@ export function useGatewayEventHandler(deps: GatewayEventDeps) {
           requestDesktopOnboarding(payload.credential_warning)
         }
 
+        if (apply) {
+          reportInstallMethodWarning(payload?.install_warning)
+        }
+
         void refreshHermesConfig()
 
         if (modelChanged || providerChanged) {
diff --git a/apps/desktop/src/app/session/hooks/use-session-actions/utils.ts b/apps/desktop/src/app/session/hooks/use-session-actions/utils.ts
index 254a58e1298..d299fe51b7e 100644
--- a/apps/desktop/src/app/session/hooks/use-session-actions/utils.ts
+++ b/apps/desktop/src/app/session/hooks/use-session-actions/utils.ts
@@ -19,7 +19,7 @@ import {
   setSessions,
   setYoloActive
 } from '@/store/session'
-import { reportBackendContract } from '@/store/updates'
+import { reportBackendContract, reportInstallMethodWarning } from '@/store/updates'
 import type { SessionCreateResponse, SessionInfo, SessionRuntimeInfo } from '@/types/hermes'
 
 import type { ClientSessionState } from '../../../types'
@@ -270,6 +270,8 @@ export function applyRuntimeInfo(info: SessionRuntimeInfo | undefined): SessionR
     requestDesktopOnboarding(info.credential_warning)
   }
 
+  reportInstallMethodWarning(info.install_warning)
+
   if (typeof info.model === 'string') {
     setCurrentModel(info.model)
     sessionState.model = info.model
diff --git a/apps/desktop/src/i18n/en.ts b/apps/desktop/src/i18n/en.ts
index 67172bc2cad..f368433ac75 100644
--- a/apps/desktop/src/i18n/en.ts
+++ b/apps/desktop/src/i18n/en.ts
@@ -116,6 +116,7 @@ export const en: Translations = {
     backendOutOfDateTitle: 'Backend out of date',
     backendOutOfDateMessage:
       'Your Hermes backend is older than this desktop build and may not work correctly. Update to align them.',
+    installMethodUnsupportedTitle: 'Unsupported install method',
     updateHermes: 'Update Hermes',
     updateReadyTitle: 'Update ready',
     updateReadyMessage: count => `${count} new change${count === 1 ? '' : 's'} available.`,
diff --git a/apps/desktop/src/i18n/ja.ts b/apps/desktop/src/i18n/ja.ts
index 7c23fb65601..989fa47ab87 100644
--- a/apps/desktop/src/i18n/ja.ts
+++ b/apps/desktop/src/i18n/ja.ts
@@ -117,6 +117,7 @@ export const ja = defineLocale({
     backendOutOfDateTitle: 'バックエンドが古いです',
     backendOutOfDateMessage:
       'Hermes バックエンドがこのデスクトップビルドより古く、正常に動作しない場合があります。更新して揃えてください。',
+    installMethodUnsupportedTitle: 'サポート対象外のインストール方法',
     updateHermes: 'Hermes を更新',
     updateReadyTitle: '更新の準備ができました',
     updateReadyMessage: count => `${count} 件の新しい変更が利用可能です。`,
diff --git a/apps/desktop/src/i18n/types.ts b/apps/desktop/src/i18n/types.ts
index 7bf02671436..6e6e8c1debd 100644
--- a/apps/desktop/src/i18n/types.ts
+++ b/apps/desktop/src/i18n/types.ts
@@ -158,6 +158,7 @@ export interface Translations {
     copyDetailFailed: string
     backendOutOfDateTitle: string
     backendOutOfDateMessage: string
+    installMethodUnsupportedTitle: string
     updateHermes: string
     updateReadyTitle: string
     updateReadyMessage: (count: number) => string
diff --git a/apps/desktop/src/i18n/zh-hant.ts b/apps/desktop/src/i18n/zh-hant.ts
index 5859569a2ae..6ce5c0d58e4 100644
--- a/apps/desktop/src/i18n/zh-hant.ts
+++ b/apps/desktop/src/i18n/zh-hant.ts
@@ -113,6 +113,7 @@ export const zhHant = defineLocale({
     copyDetailFailed: '無法複製通知詳情',
     backendOutOfDateTitle: '後端版本過舊',
     backendOutOfDateMessage: '您的 Hermes 後端早於目前的桌面版本，可能無法正常運作。請更新以保持一致。',
+    installMethodUnsupportedTitle: '不受支援的安裝方式',
     updateHermes: '更新 Hermes',
     updateReadyTitle: '有可用更新',
     updateReadyMessage: count => `有 ${count} 項新變更可用。`,
diff --git a/apps/desktop/src/i18n/zh.ts b/apps/desktop/src/i18n/zh.ts
index 4c0b14150f9..6eba08ef5c5 100644
--- a/apps/desktop/src/i18n/zh.ts
+++ b/apps/desktop/src/i18n/zh.ts
@@ -113,6 +113,7 @@ export const zh: Translations = {
     copyDetailFailed: '无法复制通知详情',
     backendOutOfDateTitle: '后端版本过旧',
     backendOutOfDateMessage: '你的 Hermes 后端早于当前桌面构建，可能无法正常工作。请更新以保持一致。',
+    installMethodUnsupportedTitle: '不受支持的安装方式',
     updateHermes: '更新 Hermes',
     updateReadyTitle: '有可用更新',
     updateReadyMessage: count => `有 ${count} 项新更改可用。`,
diff --git a/apps/desktop/src/lib/chat-messages.ts b/apps/desktop/src/lib/chat-messages.ts
index 317108a9955..2b232ad3b19 100644
--- a/apps/desktop/src/lib/chat-messages.ts
+++ b/apps/desktop/src/lib/chat-messages.ts
@@ -50,6 +50,7 @@ export type GatewayEventPayload = {
   cwd?: string
   branch?: string
   credential_warning?: string
+  install_warning?: string
   personality?: string
   usage?: Partial<UsageStats>
   // agent.terminal.output — live chunk for a read-only agent terminal tab
diff --git a/apps/desktop/src/store/updates.ts b/apps/desktop/src/store/updates.ts
index f9e76333c63..7c51c8aab32 100644
--- a/apps/desktop/src/store/updates.ts
+++ b/apps/desktop/src/store/updates.ts
@@ -111,6 +111,24 @@ function isSkewToastSnoozed(): boolean {
   return Number.isFinite(until) && Date.now() < until
 }
 
+const INSTALL_METHOD_TOAST_ID = 'install-method-not-supported'
+// Same time-based snooze pattern as the update/skew toasts: the warning is
+// re-derived from every session.info (session.create/resume/activate all
+// route through applyRuntimeInfo), so without a snooze it would re-pop on
+// every session switch even right after the user dismissed it.
+const INSTALL_METHOD_TOAST_SNOOZE_KEY = 'hermes:install-method-toast-snooze-until'
+const INSTALL_METHOD_TOAST_COOLDOWN_MS = 24 * 60 * 60 * 1000
+
+function snoozeInstallMethodToast(): void {
+  persistString(INSTALL_METHOD_TOAST_SNOOZE_KEY, String(Date.now() + INSTALL_METHOD_TOAST_COOLDOWN_MS))
+}
+
+function isInstallMethodToastSnoozed(): boolean {
+  const until = Number(storedString(INSTALL_METHOD_TOAST_SNOOZE_KEY) || 0)
+
+  return Number.isFinite(until) && Date.now() < until
+}
+
 /**
  * Guard against a desktop GUI talking to a backend that predates its contract
  * (e.g. a bb/gui-built app pointed at a `main` checkout). Rather than failing
@@ -151,6 +169,27 @@ export function reportBackendContract(contract: number | undefined): void {
   })
 }
 
+export function reportInstallMethodWarning(message: string | undefined): void {
+  if (!message) {
+    dismissNotification(INSTALL_METHOD_TOAST_ID)
+
+    return
+  }
+
+  if (isInstallMethodToastSnoozed()) {
+    return
+  }
+
+  notify({
+    durationMs: 0,
+    id: INSTALL_METHOD_TOAST_ID,
+    kind: 'warning',
+    message,
+    onDismiss: () => snoozeInstallMethodToast(),
+    title: translateNow('notifications.installMethodUnsupportedTitle')
+  })
+}
+
 /**
  * Fire a toast when an update is available, at most once per cooldown window.
  * Closing the toast — dismissing it or opening the updates window from it —
diff --git a/apps/desktop/src/types/hermes.ts b/apps/desktop/src/types/hermes.ts
index e360668c14b..3515477d8f7 100644
--- a/apps/desktop/src/types/hermes.ts
+++ b/apps/desktop/src/types/hermes.ts
@@ -399,6 +399,7 @@ export interface SessionRuntimeInfo {
   cwd?: string
   desktop_contract?: number
   fast?: boolean
+  install_warning?: string
   model?: string
   personality?: string
   provider?: string
diff --git a/hermes_cli/banner.py b/hermes_cli/banner.py
index 217eb2bb965..a596bc91d70 100644
--- a/hermes_cli/banner.py
+++ b/hermes_cli/banner.py
@@ -2,7 +2,6 @@
 
 Pure display functions with no HermesCLI state dependency.
 """
-
 import json
 import logging
 import os
@@ -322,7 +321,7 @@ def check_for_updates() -> Optional[int]:
     # both the Rich banner (build_welcome_banner) and the Ink badge
     # (branding.tsx, guarded on `typeof === 'number' && > 0`) show nothing.
     try:
-        from hermes_cli.config import detect_install_method
+        from hermes_cli.config import detect_install_method, get_project_root
         if detect_install_method() == "docker":
             return None
     except Exception:
@@ -873,17 +872,23 @@ def build_welcome_banner(console: "Console", model: str, cwd: str,
     except Exception:
         pass  # Never break the banner over an update check
 
-    # Pip-install warning — `pip install hermes-agent` is not the supported
-    # install path (it exists on PyPI for internal/CI reasons, not end users).
-    # Such installs miss the git checkout + installer-managed deps, so updates,
-    # self-update, and issue triage don't behave correctly. Warn, don't block.
+    # Unsupported install-method warning — pip/PyPI and Homebrew are no
+    # longer an officially supported distribution method (see
+    # website/docs/getting-started/platform-support.md). Such installs miss
+    # the git checkout + installer-managed deps, so updates, self-update, and
+    # issue triage don't behave correctly. Warn, don't block. NixOS is fully
+    # supported and never hits this.
     try:
-        from hermes_cli.config import detect_install_method
-        if detect_install_method() == "pip":
+        from hermes_cli.config import (
+            detect_install_method,
+            format_unsupported_install_warning,
+            is_unsupported_install_method,
+            get_project_root
+        )
+        _install_method = detect_install_method()
+        if is_unsupported_install_method(_install_method):
             right_lines.append(
-                "[bold yellow]⚠ pip install not officially supported[/]"
-                "[dim yellow] — exists for reasons other than user install; "
-                "expect instability and an inability to support issues[/]"
+                f"[bold yellow]⚠ {format_unsupported_install_warning(_install_method)}[/]"
             )
     except Exception:
         pass  # Never break the banner over the install-method check
diff --git a/hermes_cli/config.py b/hermes_cli/config.py
index 797f4d0977e..fadca5457fa 100644
--- a/hermes_cli/config.py
+++ b/hermes_cli/config.py
@@ -530,6 +530,50 @@ def recommended_update_command() -> str:
     return recommended_update_command_for_method(method)
 
 
+# =============================================================================
+# Unsupported install methods (pip, Homebrew) — deprecation notice
+# =============================================================================
+#
+# pip/PyPI and Homebrew are NOT an officially supported distribution method
+# (see website/docs/getting-started/platform-support.md, "Unsupported"
+# section). pip exists on PyPI for internal/CI reasons, not end-user installs;
+# Homebrew is a legacy packaging path. Unlike NixOS/Homebrew "managed mode"
+# (which hard-blocks config writes), this is a warn-don't-block deprecation
+# notice surfaced everywhere the user might see install-method state: the CLI
+# banner, the TUI/desktop session info panel, and ``hermes update``. NixOS
+# stays fully supported (Tier 2) and must never hit this path.
+
+PLATFORM_SUPPORT_DOCS_URL = "https://hermes-agent.nousresearch.com/docs/getting-started/platform-support"
+
+_UNSUPPORTED_INSTALL_METHODS = frozenset({"pip", "homebrew"})
+
+
+def is_unsupported_install_method(method: str) -> bool:
+    """Whether ``method`` (from ``detect_install_method()``) is deprecated."""
+    return method in _UNSUPPORTED_INSTALL_METHODS
+
+
+def unsupported_install_method_label(method: str) -> str:
+    """Human-readable name for an unsupported install method."""
+    return "pip" if method == "pip" else "Homebrew"
+
+
+def format_unsupported_install_warning(method: str) -> str:
+    """Plain-text (no markup) deprecation notice for pip/Homebrew installs.
+
+    Shared verbatim across the CLI banner, TUI/desktop ``session.info``, and
+    ``hermes update`` / ``hermes update --check`` so the wording — and the
+    docs link — stays consistent across every surface instead of drifting
+    into three slightly different warnings.
+    """
+    label = unsupported_install_method_label(method)
+    return (
+        f"{label} installs are no longer an officially supported platform and "
+        f"will not receive further updates. See {PLATFORM_SUPPORT_DOCS_URL} "
+        "for supported install methods."
+    )
+
+
 # Long-form text for ``hermes update`` / ``--check`` when running inside the
 # Docker image.  Surfaced by ``cmd_update`` and ``_cmd_update_check`` in
 # hermes_cli/main.py; lives here so the wording stays consistent and we
diff --git a/hermes_cli/main.py b/hermes_cli/main.py
index 4e483d318c3..269d6d609ea 100644
--- a/hermes_cli/main.py
+++ b/hermes_cli/main.py
@@ -8375,8 +8375,14 @@ def _cmd_update_check(branch: str = "main", *, branch_explicit: bool = False):
     on a PyPI install we surface a one-line notice instead of silently
     dropping the flag.
     """
-    from hermes_cli.config import detect_install_method
+    from hermes_cli.config import (
+        detect_install_method,
+        format_unsupported_install_warning,
+        is_unsupported_install_method,
+    )
     method = detect_install_method(PROJECT_ROOT)
+    if is_unsupported_install_method(method):
+        print(f"⚠ {format_unsupported_install_warning(method)}")
     if method == "docker":
         # Docker can't ``git fetch`` from within the container.  Surface the
         # same long-form ``docker pull`` guidance ``hermes update`` (apply
@@ -9259,10 +9265,21 @@ def cmd_update(args):
     from hermes_cli.config import (
         detect_install_method,
         format_docker_update_message,
+        format_unsupported_install_warning,
         is_managed,
+        is_unsupported_install_method,
         managed_error,
     )
 
+    # Deprecation notice for pip/Homebrew installs — printed before the
+    # managed-mode early-return below so Homebrew users (who are blocked from
+    # applying the update here) still see it. Warn, don't block: the update
+    # itself still proceeds (except Homebrew, which is managed-mode blocked
+    # for an unrelated reason — brew owns its own upgrade path).
+    _install_method_for_warning = detect_install_method(PROJECT_ROOT)
+    if is_unsupported_install_method(_install_method_for_warning):
+        print(f"⚠ {format_unsupported_install_warning(_install_method_for_warning)}")
+
     if is_managed():
         managed_error("update Hermes Agent")
         return
diff --git a/tests/hermes_cli/test_pip_install_detection.py b/tests/hermes_cli/test_pip_install_detection.py
index 673ea568759..c852b57052a 100644
--- a/tests/hermes_cli/test_pip_install_detection.py
+++ b/tests/hermes_cli/test_pip_install_detection.py
@@ -195,7 +195,33 @@ def test_banner_warns_on_pip_install(tmp_path):
         out = buf.getvalue()
 
     assert "officially" in out
-    assert "instability" in out
+    assert "platform-support" in out
+
+
+def test_banner_warns_on_homebrew_install(tmp_path):
+    """The welcome banner surfaces a warning when the install method is homebrew."""
+    import io
+    from rich.console import Console
+    from hermes_cli import banner
+
+    hh = tmp_path / ".hermes"
+    hh.mkdir()
+    (hh / ".install_method").write_text("homebrew\n")
+
+    with patch("hermes_cli.config.get_hermes_home", return_value=hh), \
+         patch("hermes_constants.get_hermes_home", return_value=hh):
+        buf = io.StringIO()
+        console = Console(file=buf, width=400, force_terminal=False, color_system=None)
+        banner.build_welcome_banner(
+            console, model="m", cwd="/tmp",
+            tools=[{"function": {"name": "terminal"}}],
+            enabled_toolsets=["terminal"],
+        )
+        out = buf.getvalue()
+
+    assert "officially" in out
+    assert "Homebrew" in out
+    assert "platform-support" in out
 
 
 def test_banner_no_pip_warning_on_git_install(tmp_path):
diff --git a/tests/test_tui_gateway_server.py b/tests/test_tui_gateway_server.py
index 6d39a252cfe..5a2c222a0fd 100644
--- a/tests/test_tui_gateway_server.py
+++ b/tests/test_tui_gateway_server.py
@@ -4610,6 +4610,25 @@ def test_session_info_includes_session_title(monkeypatch):
     assert info["title"] == "Dashboard title"
 
 
+def test_session_info_includes_install_warning_for_pip(monkeypatch):
+    """pip installs surface install_warning; git installs don't (issue: pip/brew deprecation)."""
+    monkeypatch.setattr("hermes_cli.config.detect_install_method", lambda: "pip")
+
+    info = server._session_info(types.SimpleNamespace(tools=[], model="", provider=""))
+
+    assert "install_warning" in info
+    assert "pip" in info["install_warning"]
+    assert "platform-support" in info["install_warning"]
+
+
+def test_session_info_omits_install_warning_for_git(monkeypatch):
+    monkeypatch.setattr("hermes_cli.config.detect_install_method", lambda: "git")
+
+    info = server._session_info(types.SimpleNamespace(tools=[], model="", provider=""))
+
+    assert "install_warning" not in info
+
+
 # ---------------------------------------------------------------------------
 # History-mutating commands must reject while session.running is True.
 # Without these guards, prompt.submit's post-run history write either
diff --git a/tui_gateway/server.py b/tui_gateway/server.py
index 878b28d02c2..2a261c2cc89 100644
--- a/tui_gateway/server.py
+++ b/tui_gateway/server.py
@@ -3159,6 +3159,18 @@ def _session_info(agent, session: dict | None = None) -> dict:
         "usage": _get_usage(agent),
         "profile_name": _current_profile_name(),
     }
+    try:
+        from hermes_cli.config import (
+            detect_install_method,
+            format_unsupported_install_warning,
+            is_unsupported_install_method,
+        )
+
+        _install_method = detect_install_method()
+        if is_unsupported_install_method(_install_method):
+            info["install_warning"] = format_unsupported_install_warning(_install_method)
+    except Exception:
+        pass
     try:
         from hermes_cli import __version__, __release_date__
 
diff --git a/ui-tui/src/components/branding.tsx b/ui-tui/src/components/branding.tsx
index 136b97db90c..3c9cdd5f251 100644
--- a/ui-tui/src/components/branding.tsx
+++ b/ui-tui/src/components/branding.tsx
@@ -412,6 +412,12 @@ export function SessionPanel({ info, maxWidth, sid, t }: SessionPanelProps) {
             </Text>
           </Text>
         )}
+
+        {info.install_warning && (
+          <Text bold color={t.color.warn} wrap="wrap">
+            ! {info.install_warning}
+          </Text>
+        )}
       </Box>
     </Box>
   )
diff --git a/ui-tui/src/types.ts b/ui-tui/src/types.ts
index 4f7ffa225d2..14ab98ca18d 100644
--- a/ui-tui/src/types.ts
+++ b/ui-tui/src/types.ts
@@ -150,6 +150,7 @@ export interface McpServerStatus {
 export interface SessionInfo {
   cwd?: string
   fast?: boolean
+  install_warning?: string
   lazy?: boolean
   mcp_servers?: McpServerStatus[]
   model: string