feat(gateway): add native Google Chat platform adapter

agent/prompt_builder.py

@@ -422,6 +422,18 @@ def _strip_yaml_frontmatter(content: str) -> str:
         "your response. Images are sent as native photos, and other files arrive as downloadable "
         "documents."
     ),
+    "google_chat": (
+        "You are on Google Chat, a workspace-oriented messaging platform. "
+        "Google Chat uses its own lightweight formatting — NOT standard Markdown. "
+        "Use *single asterisks* for bold, _underscores_ for italic, "
+        "~single tilde~ for strikethrough, and `backticks` for code. "
+        "Double asterisks (**) and headers (# Title) are NOT rendered — "
+        "they appear as literal characters. "
+        "For links, use <URL|display text> syntax (NOT [text](url)). "
+        "Keep messages concise and well-structured with short paragraphs. "
+        "Messages are capped at 4,096 characters — longer responses are "
+        "split automatically."
+    ),
 }
 
 # ---------------------------------------------------------------------------

cron/scheduler.py

@@ -77,7 +77,7 @@ def _resolve_cron_enabled_toolsets(job: dict, cfg: dict) -> list[str] | None:
     "telegram", "discord", "slack", "whatsapp", "signal",
     "matrix", "mattermost", "homeassistant", "dingtalk", "feishu",
     "wecom", "wecom_callback", "weixin", "sms", "email", "webhook", "bluebubbles",
-    "qqbot",
+    "qqbot", "google_chat",
 })
 
 # Platforms that support a configured cron/notification home target, mapped to
@@ -97,6 +97,7 @@ def _resolve_cron_enabled_toolsets(job: dict, cfg: dict) -> list[str] | None:
     "weixin": "WEIXIN_HOME_CHANNEL",
     "bluebubbles": "BLUEBUBBLES_HOME_CHANNEL",
     "qqbot": "QQBOT_HOME_CHANNEL",
+    "google_chat": "GOOGLE_CHAT_HOME_CHANNEL",
 }
 
 # Legacy env var names kept for back-compat.  Each entry is the current
@@ -337,6 +338,7 @@ def _deliver_result(job: dict, content: str, adapters=None, loop=None) -> Option
         "sms": Platform.SMS,
         "bluebubbles": Platform.BLUEBUBBLES,
         "qqbot": Platform.QQBOT,
+        "google_chat": Platform.GOOGLE_CHAT,
     }
 
     # Optionally wrap the content with a header/footer so the user knows this

gateway/config.py

@@ -67,6 +67,7 @@ class Platform(Enum):
     WEIXIN = "weixin"
     BLUEBUBBLES = "bluebubbles"
     QQBOT = "qqbot"
+    GOOGLE_CHAT = "google_chat"
 
 
 @dataclass
@@ -1271,6 +1272,27 @@ def _apply_env_overrides(config: GatewayConfig) -> None:
                 name=os.getenv("QQBOT_HOME_CHANNEL_NAME") or os.getenv(qq_home_name_env, "Home"),
             )
 
+    # Google Chat (via Cloud Pub/Sub)
+    google_chat_project = os.getenv("GOOGLE_CHAT_GCP_PROJECT")
+    if google_chat_project:
+        if Platform.GOOGLE_CHAT not in config.platforms:
+            config.platforms[Platform.GOOGLE_CHAT] = PlatformConfig()
+        config.platforms[Platform.GOOGLE_CHAT].enabled = True
+        config.platforms[Platform.GOOGLE_CHAT].extra.update({
+            "gcp_project": google_chat_project,
+            "pubsub_subscription": os.getenv("GOOGLE_CHAT_PUBSUB_SUBSCRIPTION", "hermes-chat-inbound-sub"),
+        })
+        google_chat_credentials = os.getenv("GOOGLE_CHAT_CREDENTIALS", "")
+        if google_chat_credentials:
+            config.platforms[Platform.GOOGLE_CHAT].extra["chat_credentials"] = google_chat_credentials
+    google_chat_home = os.getenv("GOOGLE_CHAT_HOME_CHANNEL")
+    if google_chat_home and Platform.GOOGLE_CHAT in config.platforms:
+        config.platforms[Platform.GOOGLE_CHAT].home_channel = HomeChannel(
+            platform=Platform.GOOGLE_CHAT,
+            chat_id=google_chat_home,
+            name=os.getenv("GOOGLE_CHAT_HOME_CHANNEL_NAME", "Home"),
+        )
+
     # Session settings
     idle_minutes = os.getenv("SESSION_IDLE_MINUTES")
     if idle_minutes: