diff --git a/config.example.toml b/config.example.toml
index 35478529..e92996e4 100644
--- a/config.example.toml
+++ b/config.example.toml
@@ -71,6 +71,16 @@ reasoning_effort = "max"
 # Display estimated usage in USD or CNY. Aliases `yuan` and `rmb` normalize to `cny`.
 cost_currency = "usd" # usd | cny
 
+# ─────────────────────────────────────────────────────────────────────────────────
+# Startup update check
+# ─────────────────────────────────────────────────────────────────────────────────
+# The TUI checks for newer CodeWhale releases in the background at startup.
+# Set check_for_updates = false in managed or air-gapped environments.
+# update_uri may point at a GitHub-compatible latest-release JSON endpoint.
+[update]
+check_for_updates = true
+# update_uri = "https://internal.mirror.example/codewhale/releases/latest"
+
 # ─────────────────────────────────────────────────────────────────────────────────
 # Paths
 # ─────────────────────────────────────────────────────────────────────────────────
diff --git a/crates/tui/src/config.rs b/crates/tui/src/config.rs
index 300e9d99..e7713206 100644
--- a/crates/tui/src/config.rs
+++ b/crates/tui/src/config.rs
@@ -1287,6 +1287,40 @@ pub struct AutoConfig {
     pub cost_saving: Option<bool>,
 }
 
+fn default_update_check_for_updates() -> bool {
+    true
+}
+
+/// Startup update-check configuration (`[update]` table in config.toml).
+#[derive(Debug, Clone, Deserialize, PartialEq, Eq)]
+pub struct UpdateConfig {
+    /// When false, skip the TUI startup background update check entirely.
+    #[serde(default = "default_update_check_for_updates")]
+    pub check_for_updates: bool,
+    /// Optional GitHub-compatible latest-release JSON endpoint.
+    #[serde(default)]
+    pub update_uri: Option<String>,
+}
+
+impl Default for UpdateConfig {
+    fn default() -> Self {
+        Self {
+            check_for_updates: true,
+            update_uri: None,
+        }
+    }
+}
+
+impl UpdateConfig {
+    #[must_use]
+    pub fn update_uri(&self) -> Option<&str> {
+        self.update_uri
+            .as_deref()
+            .map(str::trim)
+            .filter(|value| !value.is_empty())
+    }
+}
+
 /// Resolved CLI configuration, including defaults and environment overrides.
 #[derive(Debug, Clone, Default, Deserialize)]
 pub struct Config {
@@ -1395,6 +1429,11 @@ pub struct Config {
     #[serde(default)]
     pub auto: Option<AutoConfig>,
 
+    /// Startup update-check behavior. When absent, the TUI keeps the default
+    /// fire-and-forget latest-release check.
+    #[serde(default)]
+    pub update: Option<UpdateConfig>,
+
     /// Post-edit LSP diagnostics injection (#136). When absent, the engine
     /// applies the defaults documented in [`LspConfigToml`].
     #[serde(default)]
@@ -2458,6 +2497,12 @@ impl Config {
         self.snapshots.clone().unwrap_or_default()
     }
 
+    /// Resolve startup update-check settings with defaults applied.
+    #[must_use]
+    pub fn update_config(&self) -> UpdateConfig {
+        self.update.clone().unwrap_or_default()
+    }
+
     /// Resolve enabled features from defaults and config entries.
     #[must_use]
     pub fn features(&self) -> Features {
@@ -2696,6 +2741,11 @@ default_text_model = "{DEFAULT_TEXT_MODEL}"
 # "auto" | "off" | "low" | "medium" | "high" | "max"
 # Shift+Tab in the TUI cycles between off / high / max.
 reasoning_effort = "auto"
+
+# Startup update check
+[update]
+check_for_updates = true
+# update_uri = "https://internal.mirror.example/codewhale/releases/latest"
 "#
     );
     write_config_file_secure(&config_path, &content)
@@ -3717,6 +3767,7 @@ fn merge_config(base: Config, override_cfg: Config) -> Config {
         search: override_cfg.search.or(base.search),
         memory: override_cfg.memory.or(base.memory),
         auto: override_cfg.auto.or(base.auto),
+        update: override_cfg.update.or(base.update),
         lsp: override_cfg.lsp.or(base.lsp),
         context: ContextConfig {
             enabled: override_cfg.context.enabled.or(base.context.enabled),
@@ -4712,6 +4763,34 @@ mod tests {
         );
     }
 
+    #[test]
+    fn update_config_defaults_to_enabled_without_uri() {
+        let config = Config::default();
+        assert_eq!(config.update, None);
+        assert_eq!(config.update_config(), UpdateConfig::default());
+        assert!(config.update_config().check_for_updates);
+        assert_eq!(config.update_config().update_uri(), None);
+    }
+
+    #[test]
+    fn update_config_deserializes_disable_and_custom_uri() {
+        let config: Config = toml::from_str(
+            r#"
+            [update]
+            check_for_updates = false
+            update_uri = "https://mirror.example/releases/latest"
+            "#,
+        )
+        .expect("update config");
+
+        let update = config.update_config();
+        assert!(!update.check_for_updates);
+        assert_eq!(
+            update.update_uri(),
+            Some("https://mirror.example/releases/latest")
+        );
+    }
+
     #[test]
     fn network_policy_toml_maps_proxy_hosts_to_runtime_policy() {
         let policy: NetworkPolicyToml = toml::from_str(
diff --git a/crates/tui/src/tui/ui.rs b/crates/tui/src/tui/ui.rs
index 171f168c..779f0dc0 100644
--- a/crates/tui/src/tui/ui.rs
+++ b/crates/tui/src/tui/ui.rs
@@ -6,7 +6,7 @@ use std::path::PathBuf;
 use std::sync::{Arc, LazyLock};
 use std::time::{Duration, Instant};
 
-use anyhow::Result;
+use anyhow::{Context, Result};
 // On Windows the push/pop helpers write the escapes directly; crossterm's
 // PushKeyboardEnhancementFlags / PopKeyboardEnhancementFlags commands are
 // never referenced, so the imports are gated to avoid -D warnings failures.
@@ -43,7 +43,7 @@ use crate::commands;
 use crate::compaction::estimate_input_tokens_conservative;
 use crate::config::{
     ApiProvider, Config, DEFAULT_NVIDIA_NIM_BASE_URL, ProviderConfig, ProvidersConfig, StatusItem,
-    save_provider_auth_mode_for,
+    UpdateConfig, save_provider_auth_mode_for,
 };
 use crate::config_ui::{self, ConfigUiMode, WebConfigSession, WebConfigSessionEvent};
 use crate::core::engine::{EngineConfig, EngineHandle, spawn_engine};
@@ -999,27 +999,8 @@ async fn run_event_loop(
     // Fire-and-forget version check — runs once per session in the
     // background. On success, a short status toast advertises the update
     // without replacing the user's configured footer/status-line chips.
-    let mut version_check: Option<tokio::task::JoinHandle<Option<String>>> = Some({
-        let current = env!("CARGO_PKG_VERSION").to_string();
-        tokio::spawn(async move {
-            let client = match reqwest::Client::builder()
-                .user_agent("codewhale-version-check")
-                .timeout(std::time::Duration::from_secs(5))
-                .build()
-            {
-                Ok(c) => c,
-                Err(_) => return None,
-            };
-            let resp = client
-                .get("https://api.github.com/repos/Hmbown/CodeWhale/releases/latest")
-                .header("Accept", "application/vnd.github+json")
-                .send()
-                .await
-                .ok()?;
-            let json: serde_json::Value = resp.json().await.ok()?;
-            version_hint_from_release_json(&json, &current)
-        })
-    });
+    let mut version_check: Option<tokio::task::JoinHandle<Option<String>>> =
+        spawn_startup_version_check(config.update_config());
 
     // Fire a one-shot initial balance fetch for DeepSeek providers
     // so the footer chip shows balance on the first frame without
@@ -8668,12 +8649,119 @@ fn extract_reasoning_header(text: &str) -> Option<String> {
     }
 }
 
+#[derive(Debug, Clone, PartialEq, Eq)]
+enum StartupVersionCheckSource {
+    Disabled,
+    ConfiguredUrl(String),
+    ReleaseResolver,
+}
+
+fn startup_version_check_source(config: &UpdateConfig) -> StartupVersionCheckSource {
+    if !config.check_for_updates {
+        return StartupVersionCheckSource::Disabled;
+    }
+    if let Some(update_uri) = config.update_uri() {
+        return StartupVersionCheckSource::ConfiguredUrl(update_uri.to_string());
+    }
+    StartupVersionCheckSource::ReleaseResolver
+}
+
+fn spawn_startup_version_check(
+    config: UpdateConfig,
+) -> Option<tokio::task::JoinHandle<Option<String>>> {
+    let source = startup_version_check_source(&config);
+    if source == StartupVersionCheckSource::Disabled {
+        return None;
+    }
+
+    let current = env!("CARGO_PKG_VERSION").to_string();
+    Some(tokio::spawn(async move {
+        version_hint_from_startup_source(source, &current).await
+    }))
+}
+
+async fn version_hint_from_startup_source(
+    source: StartupVersionCheckSource,
+    current: &str,
+) -> Option<String> {
+    match source {
+        StartupVersionCheckSource::Disabled => None,
+        StartupVersionCheckSource::ConfiguredUrl(url) => {
+            match version_hint_from_configured_update_uri(&url, current).await {
+                Ok(hint) => hint,
+                Err(_) => version_hint_from_release_mirror_env(current).await,
+            }
+        }
+        StartupVersionCheckSource::ReleaseResolver => {
+            if release_mirror_env_configured() {
+                return version_hint_from_release_mirror_env(current).await;
+            }
+
+            let body = codewhale_release::fetch_release_json_async(
+                codewhale_release::LATEST_RELEASE_URL,
+                "latest release",
+            )
+            .await
+            .ok()?;
+            let json: serde_json::Value = serde_json::from_str(&body).ok()?;
+            version_hint_from_release_json(&json, current)
+        }
+    }
+}
+
+async fn version_hint_from_release_mirror_env(current: &str) -> Option<String> {
+    if !release_mirror_env_configured() {
+        return None;
+    }
+    let tag =
+        codewhale_release::latest_release_tag_async(codewhale_release::ReleaseChannel::Stable)
+            .await
+            .ok()?;
+    version_hint_from_latest_tag(&tag, current)
+}
+
+fn release_mirror_env_configured() -> bool {
+    let version = codewhale_release::update_version_from_env()
+        .unwrap_or_else(|| env!("CARGO_PKG_VERSION").to_string());
+    codewhale_release::release_base_url_from_env(&version).is_some()
+}
+
+async fn version_hint_from_configured_update_uri(
+    update_uri: &str,
+    current: &str,
+) -> Result<Option<String>> {
+    let body = codewhale_release::fetch_release_json_async(update_uri, "configured latest release")
+        .await?;
+    let json: serde_json::Value = serde_json::from_str(&body).with_context(|| {
+        format!("failed to parse release JSON from configured URI {update_uri}")
+    })?;
+    Ok(version_hint_from_custom_release_json(&json, current))
+}
+
 fn version_hint_from_release_json(json: &serde_json::Value, current: &str) -> Option<String> {
     if !release_has_required_assets(json) {
         return None;
     }
 
     let tag = json["tag_name"].as_str()?;
+    version_hint_from_latest_tag(tag, current)
+}
+
+fn version_hint_from_custom_release_json(
+    json: &serde_json::Value,
+    current: &str,
+) -> Option<String> {
+    if !release_is_publishable(json) {
+        return None;
+    }
+    if json.get("assets").is_some() && !release_has_required_assets(json) {
+        return None;
+    }
+    let tag = json["tag_name"].as_str()?;
+    version_hint_from_latest_tag(tag, current)
+}
+
+fn version_hint_from_latest_tag(tag: &str, current: &str) -> Option<String> {
     let latest = tag.trim_start_matches('v');
     if !is_newer_version(latest, current) {
         return None;
@@ -8685,18 +8773,7 @@ fn version_hint_from_release_json(json: &serde_json::Value, current: &str) -> Op
 }
 
 fn release_has_required_assets(json: &serde_json::Value) -> bool {
-    if json
-        .get("draft")
-        .and_then(serde_json::Value::as_bool)
-        .unwrap_or(false)
-    {
-        return false;
-    }
-    if json
-        .get("prerelease")
-        .and_then(serde_json::Value::as_bool)
-        .unwrap_or(false)
-    {
+    if !release_is_publishable(json) {
         return false;
     }
 
@@ -8705,6 +8782,17 @@ fn release_has_required_assets(json: &serde_json::Value) -> bool {
         .all(|required| release_has_uploaded_asset(json, required))
 }
 
+fn release_is_publishable(json: &serde_json::Value) -> bool {
+    !json
+        .get("draft")
+        .and_then(serde_json::Value::as_bool)
+        .unwrap_or(false)
+        && !json
+            .get("prerelease")
+            .and_then(serde_json::Value::as_bool)
+            .unwrap_or(false)
+}
+
 fn release_has_uploaded_asset(json: &serde_json::Value, required: &str) -> bool {
     let Some(assets) = json.get("assets").and_then(serde_json::Value::as_array) else {
         return false;
diff --git a/crates/tui/src/tui/ui/tests.rs b/crates/tui/src/tui/ui/tests.rs
index 51240f01..82e50854 100644
--- a/crates/tui/src/tui/ui/tests.rs
+++ b/crates/tui/src/tui/ui/tests.rs
@@ -2868,6 +2868,45 @@ fn version_hint_ignores_draft_prerelease_and_current_versions() {
     assert!(version_hint_from_release_json(&current, "0.8.46").is_none());
 }
 
+#[test]
+fn startup_version_check_source_respects_update_config() {
+    assert_eq!(
+        startup_version_check_source(&UpdateConfig {
+            check_for_updates: false,
+            update_uri: Some("https://mirror.example/releases/latest".to_string()),
+        }),
+        StartupVersionCheckSource::Disabled
+    );
+
+    assert_eq!(
+        startup_version_check_source(&UpdateConfig {
+            check_for_updates: true,
+            update_uri: Some("  https://mirror.example/releases/latest  ".to_string()),
+        }),
+        StartupVersionCheckSource::ConfiguredUrl(
+            "https://mirror.example/releases/latest".to_string()
+        )
+    );
+
+    assert_eq!(
+        startup_version_check_source(&UpdateConfig::default()),
+        StartupVersionCheckSource::ReleaseResolver
+    );
+}
+
+#[test]
+fn custom_update_uri_accepts_tag_only_release_json() {
+    let json = serde_json::json!({
+        "tag_name": "v0.8.47",
+        "draft": false,
+        "prerelease": false,
+    });
+
+    let hint = version_hint_from_custom_release_json(&json, "0.8.46")
+        .expect("tag-only custom metadata should be enough for mirrors");
+    assert!(hint.contains("v0.8.47 available"));
+}
+
 #[test]
 #[cfg(any(unix, windows))]
 fn external_url_launcher_does_not_wait_for_browser_process() {
diff --git a/crates/tui/tests/qa_pty.rs b/crates/tui/tests/qa_pty.rs
index d5d4b5f5..8e9a8644 100644
--- a/crates/tui/tests/qa_pty.rs
+++ b/crates/tui/tests/qa_pty.rs
@@ -13,6 +13,7 @@
 #[path = "support/qa_harness/mod.rs"]
 mod qa_harness;
 
+use std::sync::{Mutex, MutexGuard};
 use std::time::Duration;
 
 use qa_harness::harness::{Harness, make_sealed_workspace};
@@ -20,6 +21,13 @@ use qa_harness::keys;
 
 const BOOT_TIMEOUT: Duration = Duration::from_secs(15);
 const KEY_TIMEOUT: Duration = Duration::from_secs(5);
+static QA_PTY_TEST_LOCK: Mutex<()> = Mutex::new(());
+
+fn qa_pty_test_lock() -> MutexGuard<'static, ()> {
+    QA_PTY_TEST_LOCK
+        .lock()
+        .unwrap_or_else(|poison| poison.into_inner())
+}
 
 fn boot_minimal() -> anyhow::Result<(qa_harness::harness::SealedWorkspace, Harness)> {
     let ws = make_sealed_workspace()?;
@@ -95,6 +103,7 @@ fn assert_viewport_starts_at_top(frame: &qa_harness::Frame) {
 /// broken before we worry about any scenario.
 #[test]
 fn smoke_boot_paints_composer() -> anyhow::Result<()> {
+    let _guard = qa_pty_test_lock();
     let (_ws, mut h) = boot_minimal()?;
 
     // The composer panel border is labelled "Composer" — wait for it.
@@ -115,6 +124,7 @@ fn smoke_boot_paints_composer() -> anyhow::Result<()> {
 /// origin/scroll-region state must not leave blank rows above the TUI.
 #[test]
 fn viewport_origin_stays_row_zero_after_failed_turn() -> anyhow::Result<()> {
+    let _guard = qa_pty_test_lock();
     let (_ws, mut h) = boot_minimal_without_retry()?;
     h.wait_for_text("Composer", BOOT_TIMEOUT)?;
     assert_viewport_starts_at_top(h.frame());
@@ -142,6 +152,7 @@ fn viewport_origin_stays_row_zero_after_failed_turn() -> anyhow::Result<()> {
 /// we lean on it for real scenarios.
 #[test]
 fn smoke_keystroke_reaches_composer() -> anyhow::Result<()> {
+    let _guard = qa_pty_test_lock();
     let (_ws, mut h) = boot_minimal()?;
     h.wait_for_text("Composer", BOOT_TIMEOUT)?;
 
@@ -157,6 +168,7 @@ fn smoke_keystroke_reaches_composer() -> anyhow::Result<()> {
 /// skills directory.
 #[test]
 fn skills_menu_shows_local_and_global_skills() -> anyhow::Result<()> {
+    let _guard = qa_pty_test_lock();
     let ws = make_sealed_workspace()?;
     write_skill(ws.user_skills_dir(), "global-alpha", "Global alpha skill")?;
     write_skill(
@@ -182,6 +194,7 @@ fn skills_menu_shows_local_and_global_skills() -> anyhow::Result<()> {
 
     h.wait_for_text("Composer", BOOT_TIMEOUT)?;
     h.send(keys::key::text("/skills"))?;
+    h.wait_for_text("/skills", KEY_TIMEOUT)?;
     h.wait_for_idle(Duration::from_millis(300), Duration::from_secs(2))?;
     h.send(keys::key::enter())?;
     h.wait_for_text("Available skills", KEY_TIMEOUT)?;
@@ -210,6 +223,7 @@ fn skills_menu_shows_local_and_global_skills() -> anyhow::Result<()> {
 /// holding the text, not start a turn.
 #[test]
 fn paste_bracketed_with_trailing_newline_does_not_autosubmit() -> anyhow::Result<()> {
+    let _guard = qa_pty_test_lock();
     let (_ws, mut h) = boot_minimal()?;
     h.wait_for_text("Composer", BOOT_TIMEOUT)?;
 
@@ -250,6 +264,7 @@ fn paste_bracketed_with_trailing_newline_does_not_autosubmit() -> anyhow::Result
 /// This is the Windows / PowerShell repro from #1073.
 #[test]
 fn paste_unbracketed_with_trailing_newline_does_not_autosubmit() -> anyhow::Result<()> {
+    let _guard = qa_pty_test_lock();
     let (_ws, mut h) = boot_minimal()?;
     h.wait_for_text("Composer", BOOT_TIMEOUT)?;
     // Let the boot fully settle so input handling is wired up.
diff --git a/docs/CONFIGURATION.md b/docs/CONFIGURATION.md
index e6aab6d7..9344b830 100644
--- a/docs/CONFIGURATION.md
+++ b/docs/CONFIGURATION.md
@@ -168,6 +168,37 @@ distinct set of commands (`auth`, `config`, `model`, `thread`, `sandbox`,
 `app-server`, `mcp-server`, `completion`) and forwards plain prompts to
 `codewhale-tui`.
 
+### Startup Update Checks
+
+By default, the TUI starts a background check for the latest stable CodeWhale
+release and shows a short toast only when a newer release is available and the
+official release assets are complete.
+
+Disable the startup check entirely for air-gapped, corporate-proxy, or managed
+desktop environments:
+
+```toml
+[update]
+check_for_updates = false
+```
+
+To redirect the startup check, set `update_uri` to an internal endpoint that
+returns GitHub-compatible latest-release JSON. Minimal mirror metadata with a
+`tag_name` field is accepted; if `assets` are present, CodeWhale requires the
+same uploaded asset set as the official release before showing the toast.
+
+```toml
+[update]
+check_for_updates = true
+update_uri = "https://internal.mirror.example/codewhale/releases/latest"
+```
+
+When `update_uri` is not set, startup checks honor release mirror environment
+variables such as `CODEWHALE_RELEASE_BASE_URL` before falling back to the
+official GitHub API endpoint. If a configured `update_uri` cannot be fetched or
+parsed and a release mirror env var is set, the TUI falls back to that mirror
+instead of failing startup.
+
 ## Profiles
 
 You can define multiple profiles in the same file:
@@ -311,6 +342,9 @@ Remaining variables:
 - `CODEWHALE_HOME` (override the base data directory; defaults to `~/.codewhale`).
   If you previously exported `DEEPSEEK_HOME`, rename it to `CODEWHALE_HOME`;
   the old env var is not used for new CodeWhale state paths.
+- `CODEWHALE_RELEASE_BASE_URL` (release asset mirror used by `codewhale update`
+  and by TUI startup update checks when `[update].update_uri` is not set, or as
+  a fallback when that configured URI cannot be fetched)
 - `DEEPSEEK_AUTOMATIONS_DIR` (override the automations storage directory; uses
   `~/.codewhale/automations` when that directory exists, otherwise the legacy
   `~/.deepseek/automations` path)