diff --git a/crates/openab-core/src/cron.rs b/crates/openab-core/src/cron.rs
index f507f9bfc..2d3841460 100644
--- a/crates/openab-core/src/cron.rs
+++ b/crates/openab-core/src/cron.rs
@@ -238,7 +238,18 @@ pub fn should_fire(schedule: &Schedule, tz: Tz) -> bool {
 }
 
 /// Known platforms that have adapter support.
-const VALID_PLATFORMS: &[&str] = &["discord", "slack", "telegram"];
+const VALID_PLATFORMS: &[&str] = &["discord", "slack", "telegram", "googlechat"];
+
+fn should_create_cron_thread(job: &CronJobConfig) -> bool {
+    job.thread_id.is_none() && job.platform != "googlechat"
+}
+
+fn cron_sender_thread_id(channel: &ChannelRef) -> Option<String> {
+    channel
+        .thread_id
+        .clone()
+        .or_else(|| channel.parent_id.as_ref().map(|_| channel.channel_id.clone()))
+}
 
 /// Validate all cronjob configs (fail-fast on bad cron expressions or timezones).
 pub fn validate_cronjobs(
@@ -660,9 +671,7 @@ async fn fire_cronjob(
         }
     };
 
-    let reply_channel = if job.thread_id.is_some() {
-        thread_channel.clone()
-    } else {
+    let reply_channel = if should_create_cron_thread(job) {
         let thread_name = format::shorten_thread_name(&job.message);
         match adapter
             .create_thread(&thread_channel, &trigger_msg, &thread_name)
@@ -692,6 +701,8 @@ async fn fire_cronjob(
                 return;
             }
         }
+    } else {
+        thread_channel.clone()
     };
 
     let sender = SenderContext {
@@ -705,10 +716,7 @@ async fn fire_cronjob(
             .as_deref()
             .unwrap_or(&reply_channel.channel_id)
             .to_string(),
-        thread_id: reply_channel
-            .thread_id
-            .clone()
-            .or(Some(reply_channel.channel_id.clone())),
+        thread_id: cron_sender_thread_id(&reply_channel),
         is_bot: true,
         timestamp: Some(Utc::now().to_rfc3339()),
         message_id: None, // cron jobs don't originate from a message
@@ -1546,6 +1554,66 @@ message = "a"
         }
     }
 
+    #[test]
+    fn googlechat_cron_stays_top_level_without_explicit_thread() {
+        let mut job = test_cron_job();
+        job.platform = "googlechat".into();
+
+        assert!(!should_create_cron_thread(&job));
+
+        job.thread_id = Some("spaces/TEST/threads/THREAD".into());
+        assert!(!should_create_cron_thread(&job));
+    }
+
+    #[test]
+    fn thread_capable_cron_platform_creates_thread_when_unspecified() {
+        let job = test_cron_job();
+
+        assert!(should_create_cron_thread(&job));
+    }
+
+    #[test]
+    fn googlechat_top_level_sender_has_no_thread_id() {
+        let channel = ChannelRef {
+            platform: "googlechat".into(),
+            channel_id: "spaces/TEST".into(),
+            thread_id: None,
+            parent_id: None,
+            origin_event_id: None,
+        };
+
+        assert_eq!(cron_sender_thread_id(&channel), None);
+    }
+
+    #[test]
+    fn cron_sender_preserves_explicit_thread_id() {
+        let channel = ChannelRef {
+            platform: "googlechat".into(),
+            channel_id: "spaces/TEST".into(),
+            thread_id: Some("spaces/TEST/threads/THREAD".into()),
+            parent_id: None,
+            origin_event_id: None,
+        };
+
+        assert_eq!(
+            cron_sender_thread_id(&channel).as_deref(),
+            Some("spaces/TEST/threads/THREAD")
+        );
+    }
+
+    #[test]
+    fn cron_sender_uses_child_channel_id_for_thread_platforms() {
+        let channel = ChannelRef {
+            platform: "discord".into(),
+            channel_id: "thread-456".into(),
+            thread_id: None,
+            parent_id: Some("channel-123".into()),
+            origin_event_id: None,
+        };
+
+        assert_eq!(cron_sender_thread_id(&channel).as_deref(), Some("thread-456"));
+    }
+
     // --- validate_cronjobs tests ---
 
     #[test]
@@ -1568,6 +1636,17 @@ message = "a"
         assert!(validate_cronjobs(&jobs, &["discord"]).is_ok());
     }
 
+    #[test]
+    fn validate_cronjobs_googlechat_passes_when_configured() {
+        let mut job = test_cron_job();
+        job.platform = "googlechat".into();
+        job.channel = "spaces/TEST".into();
+        job.disable_on_success = None;
+        job.disable_on_success_match = None;
+
+        assert!(validate_cronjobs(&[job], &["googlechat"]).is_ok());
+    }
+
     #[test]
     fn validate_cronjobs_invalid_cron_fails() {
         let jobs = vec![CronJobConfig {
diff --git a/docs/cronjob.md b/docs/cronjob.md
index 8ff7260bd..7623cefea 100644
--- a/docs/cronjob.md
+++ b/docs/cronjob.md
@@ -44,9 +44,9 @@ thread_id = ""                               # optional: post to existing thread
 |-------|----------|---------|-------------|
 | `enabled` | | `true` | Set `false` to disable without removing the entry |
 | `schedule` | ✅ | — | 5-field POSIX cron expression |
-| `channel` | ✅ | — | Discord channel/thread ID, Slack channel ID, or Telegram chat ID |
+| `channel` | ✅ | — | Discord channel/thread ID, Slack channel ID, Telegram chat ID, or Google Chat space name |
 | `message` | ✅ | — | Message sent to the agent as a prompt |
-| `platform` | | `"discord"` | `"discord"`, `"slack"`, or `"telegram"` (requires `telegram` feature) |
+| `platform` | | `"discord"` | `"discord"`, `"slack"`, `"telegram"`, or `"googlechat"` (non-default platforms require their feature) |
 | `sender_name` | | `"openab-cron"` | Attribution shown in prompt context |
 | `timezone` | | `"UTC"` | IANA timezone (e.g. `"America/New_York"`, `"Europe/Berlin"`) |
 | `thread_id` | | — | Post into an existing thread instead of the channel |
@@ -120,6 +120,14 @@ channel = "176096071"
 message = "講一個冷笑話"
 platform = "telegram"
 sender_name = "JokeBot"
+
+[[cron.jobs]]
+schedule = "0 9 * * 1-5"
+channel = "spaces/AAAA1234567"
+message = "summarize the new support escalations"
+platform = "googlechat"
+sender_name = "SupportDigest"
+timezone = "Asia/Taipei"
 ```
 
 ## Helm Deployment
@@ -338,9 +346,12 @@ Use `sender_name` to distinguish different scheduled tasks in logs and thread ti
 | `discord` | (always enabled) | `[discord]` section in config.toml |
 | `slack` | `--features slack` | `[slack]` section in config.toml |
 | `telegram` | `--features telegram` | `[telegram]` section in config.toml **or** `TELEGRAM_BOT_TOKEN` env var |
+| `googlechat` | `--features googlechat` | `[googlechat] enabled = true` in config.toml **or** `GOOGLE_CHAT_ENABLED=true` env var, plus credentials (`sa_key_json`/`sa_key_file`/`access_token` fields or their `GOOGLE_CHAT_*` env equivalents) |
 
 > **Note:** The `channel` field for Telegram should be the numeric chat ID (e.g. `"176096071"`). Use [@userinfobot](https://t.me/userinfobot) or the Telegram Bot API `getUpdates` to find your chat ID.
 
+For Google Chat, use the space resource name (for example, `"spaces/AAAA1234567"`). Jobs without `thread_id` stay at the top level of the space because Google Chat does not implement OpenAB's `create_topic` command. To post into an existing thread, set `thread_id` to its full Google Chat thread resource name.
+
 ## When to Use External Schedulers Instead
 
 Config-driven cron covers the 80% use case: "send this message at this time." For advanced needs, use external schedulers:
diff --git a/docs/platforms/schema/googlechat.toml b/docs/platforms/schema/googlechat.toml
index 4bd02224e..375e62663 100644
--- a/docs/platforms/schema/googlechat.toml
+++ b/docs/platforms/schema/googlechat.toml
@@ -229,9 +229,9 @@ pr      = ""
 
 [[openab_features]]
 feature = "cron_dispatch"
-status  = "not_implemented"
-note    = "Not wired for scheduled cron dispatch: `VALID_PLATFORMS` (cron.rs) covers only discord/slack/telegram and no adapter is registered for this platform in `cron_adapters`, so `cronjob.toml` jobs targeting it are rejected at startup by `validate_cronjobs`."
-source  = []
+status  = "implemented"
+note    = "`cronjob.toml` jobs with `platform = \"googlechat\"` fire through the unified adapter when the `googlechat` feature is compiled and the platform is enabled (`[googlechat] enabled = true` or `GOOGLE_CHAT_ENABLED` env — config-first, per the first-class-platform-config ADR). Jobs without an explicit `thread_id` remain at the top level of the configured space because Google Chat does not implement the gateway `create_topic` command."
+source  = ["crates/openab-core/src/cron.rs#VALID_PLATFORMS", "crates/openab-core/src/cron.rs#fire_cronjob", "src/main.rs#cron_adapters"]
 pr      = ""
 
 
diff --git a/src/main.rs b/src/main.rs
index 2aabd9f0b..4d9377e20 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -686,6 +686,16 @@ async fn main() -> anyhow::Result<()> {
     if cfg.telegram.is_some() || std::env::var("TELEGRAM_BOT_TOKEN").is_ok() {
         configured_platforms.push("telegram");
     }
+    #[cfg(feature = "googlechat")]
+    if cfg
+        .googlechat
+        .clone()
+        .unwrap_or_default()
+        .resolve()
+        .enabled
+    {
+        configured_platforms.push("googlechat");
+    }
     cron::validate_cronjobs(&cfg.cron.jobs, &configured_platforms)?;
 
     // Spawn Slack adapter (background task)
@@ -1180,6 +1190,10 @@ async fn main() -> anyhow::Result<()> {
         if let Some(ref a) = shared_unified_adapter {
             cron_adapters.insert("telegram".into(), a.clone());
         }
+        #[cfg(feature = "googlechat")]
+        if let Some(ref a) = shared_unified_adapter {
+            cron_adapters.insert("googlechat".into(), a.clone());
+        }
         let cron_platforms: Vec<String> =
             configured_platforms.iter().map(|s| s.to_string()).collect();
         info!(baseline = cronjobs.len(), usercron = ?usercron_path, "starting cron scheduler");