diff --git a/changelog.d/9047-telemetry-master-opt-out.md b/changelog.d/9047-telemetry-master-opt-out.md
new file mode 100644
index 0000000000..de3cbc2754
--- /dev/null
+++ b/changelog.d/9047-telemetry-master-opt-out.md
@@ -0,0 +1,10 @@
+### Fixed
+
+- Treat the first-run telemetry decision as the master consent gate. Declining
+  it, leaving it unanswered, setting `PERRY_NO_TELEMETRY=1`, or running in CI
+  now prevents generic usage events, beta-error reports, and compatibility
+  reports from being sent.
+
+- Fail closed for existing configs that have `telemetry.enabled = false` but
+  `compatibility_reports = "on"`, and re-check consent immediately before each
+  Chirp request so an opt-out made while an event is queued still wins.
diff --git a/crates/perry/src/compat_reports.rs b/crates/perry/src/compat_reports.rs
index 27a9fcbfd4..f0230a1863 100644
--- a/crates/perry/src/compat_reports.rs
+++ b/crates/perry/src/compat_reports.rs
@@ -105,15 +105,13 @@ impl ReportSink for QueueSink {
     }
 }
 
-/// Read the active `compatibility_reports` mode for this process,
-/// honouring env-level overrides (`PERRY_NO_TELEMETRY=1`, `CI=true`).
+/// Read the active `compatibility_reports` mode for this process, honouring
+/// the master consent and env-level overrides (`PERRY_NO_TELEMETRY=1`,
+/// `CI=true`).
 pub(crate) fn active_mode() -> CompatibilityReports {
-    if telemetry::should_skip_telemetry() {
-        return CompatibilityReports::Off;
-    }
-    load_telemetry_config()
-        .map(|c| c.compatibility_reports)
-        .unwrap_or(CompatibilityReports::Ask)
+    telemetry::active_telemetry_config()
+        .map(|config| config.compatibility_reports)
+        .unwrap_or(CompatibilityReports::Off)
 }
 
 /// Install the diagnostic sink so HIR/codegen emission sites enqueue
@@ -435,6 +433,10 @@ fn persist_mode(mode: CompatibilityReports) {
 /// POST a single compatibility report to Chirp. Best-effort; failures are
 /// silently swallowed (this is opt-in background telemetry).
 fn send_compat_report(report: &CompatibilityReport) {
+    if !telemetry::is_telemetry_enabled() {
+        return;
+    }
+
     let body = match serde_json::to_value(report) {
         Ok(v) => v,
         Err(_) => return,
@@ -442,6 +444,12 @@ fn send_compat_report(report: &CompatibilityReport) {
     let client_id = report.client_id.clone();
 
     std::thread::spawn(move || {
+        // The master opt-out may have changed while this report was queued.
+        // Check again at the network boundary and fail closed.
+        if !telemetry::is_telemetry_enabled() {
+            return;
+        }
+
         let client = match reqwest::blocking::Client::builder()
             .connect_timeout(std::time::Duration::from_secs(3))
             .timeout(std::time::Duration::from_secs(5))
diff --git a/crates/perry/src/main.rs b/crates/perry/src/main.rs
index d55ea7ca07..80ec75f1d8 100644
--- a/crates/perry/src/main.rs
+++ b/crates/perry/src/main.rs
@@ -439,9 +439,9 @@ fn main_inner() -> Result<()> {
     };
 
     // #849: install the compat-report sink so diagnostic emission sites
-    // can enqueue reports. Honors `compatibility_reports = "off"` (skips
-    // installation entirely) and `PERRY_NO_TELEMETRY=1`/`CI=true` (same
-    // env overrides as the generic telemetry channel).
+    // can enqueue reports. The first-run `telemetry.enabled` consent is the
+    // master gate; `compatibility_reports = "off"` and the environment-level
+    // overrides can disable this channel further.
     compat_reports::install_sink();
 
     // Resolve the update policy ONCE, here, and use it at both hook sites.
diff --git a/crates/perry/src/telemetry.rs b/crates/perry/src/telemetry.rs
index 61e6b3a878..b316bb0bd1 100644
--- a/crates/perry/src/telemetry.rs
+++ b/crates/perry/src/telemetry.rs
@@ -1,7 +1,8 @@
 //! Anonymous usage statistics for Perry CLI
 //!
 //! Opt-in telemetry via Chirp API. On first interactive run, the user is asked
-//! once if stats collection is OK (default: yes). All telemetry is fire-and-forget
+//! once if stats collection is OK (default: yes). Declining that prompt is a
+//! master opt-out for every telemetry channel. All telemetry is fire-and-forget
 //! on background threads — never slows down the CLI.
 
 use serde::{Deserialize, Serialize};
@@ -22,9 +23,9 @@ const CHIRP_KEY: &str = "testkey123";
 const CONNECT_TIMEOUT: std::time::Duration = std::time::Duration::from_secs(3);
 const REQUEST_TIMEOUT: std::time::Duration = std::time::Duration::from_secs(5);
 
-/// Tri-state setting for the #849 opt-in compatibility-report channel.
-/// Decoupled from `enabled` (generic usage analytics) so users can opt in
-/// to one without the other.
+/// Tri-state setting for the #849 compatibility-report channel.
+/// `TelemetryConfig::enabled` is the master gate; this setting can further
+/// restrict compatibility reports after telemetry has been enabled.
 #[derive(Default, Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize)]
 #[serde(rename_all = "lowercase")]
 pub(crate) enum CompatibilityReports {
@@ -53,24 +54,21 @@ pub(crate) struct TelemetryConfig {
     pub(crate) enabled: bool,
     #[serde(default)]
     pub(crate) client_id: String,
-    /// #849: opt-in compatibility reports. Off by default in code (`Ask`
-    /// is the variant default but `#[serde(default)]` means existing
-    /// installs without the field get `Off` until they upgrade — see
-    /// `compatibility_reports_default`).
+    /// #849: compatibility reports. This setting is ignored unless the
+    /// master `enabled` consent is true.
     #[serde(default = "compatibility_reports_default")]
     pub(crate) compatibility_reports: CompatibilityReports,
 }
 
-/// Existing users (config.toml predates #849) get `Ask` so they see the
-/// prompt next time a gap is hit. New installs running through
-/// `init_and_check_consent()` also land on `Ask`. Set explicitly to `Off`
-/// to opt out at the file level.
+/// Telemetry-enabled users whose config predates #849 get `Ask` so they see
+/// the focused prompt next time a compatibility gap is hit. Master opt-outs
+/// remain off regardless of this default.
 fn compatibility_reports_default() -> CompatibilityReports {
     CompatibilityReports::Ask
 }
 
 /// Returns true if telemetry should be skipped entirely (explicit opt-out).
-pub(crate) fn should_skip_telemetry() -> bool {
+fn should_skip_telemetry() -> bool {
     if std::env::var("PERRY_NO_TELEMETRY").is_ok_and(|v| v == "1" || v == "true") {
         return true;
     }
@@ -80,6 +78,28 @@ pub(crate) fn should_skip_telemetry() -> bool {
     false
 }
 
+fn apply_master_consent(
+    config: Option<TelemetryConfig>,
+    environment_opt_out: bool,
+) -> Option<TelemetryConfig> {
+    if environment_opt_out {
+        return None;
+    }
+    config.filter(|config| config.enabled)
+}
+
+/// Return the telemetry config only after the user has granted the master
+/// consent and no environment-level override disables it. Every network
+/// telemetry path must use this gate, including paths that do not go through
+/// `main`'s `telemetry_active` flag.
+pub(crate) fn active_telemetry_config() -> Option<TelemetryConfig> {
+    apply_master_consent(load_telemetry_config(), should_skip_telemetry())
+}
+
+pub(crate) fn is_telemetry_enabled() -> bool {
+    active_telemetry_config().is_some()
+}
+
 /// Returns true if we should skip the interactive consent prompt
 /// (non-TTY environments can't prompt, but should still send if already consented).
 fn should_skip_consent_prompt() -> bool {
@@ -146,20 +166,26 @@ fn prompt_consent() -> bool {
         .interact()
         .unwrap_or(false);
 
-    let config = TelemetryConfig {
-        enabled: consent,
-        client_id: generate_client_id(),
-        // Generic analytics consent prompt doesn't speak for the
-        // separate #849 compat-report channel — leave it on `Ask` so
-        // the user gets a focused, in-context prompt the first time
-        // a gap actually fires.
-        compatibility_reports: CompatibilityReports::Ask,
-    };
-    save_telemetry_config(&config);
+    save_telemetry_config(&config_for_consent(consent));
 
     consent
 }
 
+fn config_for_consent(consent: bool) -> TelemetryConfig {
+    TelemetryConfig {
+        enabled: consent,
+        client_id: generate_client_id(),
+        // A no at the first-run prompt means no telemetry of any kind.
+        // Opted-in users still get the focused, in-context prompt before
+        // the first compatibility report is sent.
+        compatibility_reports: if consent {
+            CompatibilityReports::Ask
+        } else {
+            CompatibilityReports::Off
+        },
+    }
+}
+
 /// Check skip conditions, load config, prompt if needed.
 /// Returns true if telemetry is active for this session.
 pub(crate) fn init_and_check_consent() -> bool {
@@ -178,9 +204,9 @@ pub(crate) fn init_and_check_consent() -> bool {
 /// Send an event on a background thread. The thread is tracked so `flush()`
 /// can wait for it before process exit. All errors are silently ignored.
 pub(crate) fn send_event(event: &str, dims: &[(&str, &str)]) {
-    let config = match load_telemetry_config() {
-        Some(c) if c.enabled => c,
-        _ => return,
+    let config = match active_telemetry_config() {
+        Some(config) => config,
+        None => return,
     };
 
     let event = event.to_string();
@@ -228,6 +254,12 @@ pub(crate) fn flush() {
 /// Actual HTTP POST to Chirp API.
 /// Chirp expects `dims` object with known keys (platform, target, version, status, etc.).
 fn send_event_blocking(event: &str, dims: &[(String, String)], client_id: &str) {
+    // Re-check immediately before constructing the HTTP client. This keeps an
+    // opt-out made while a background event is queued from racing with send.
+    if !is_telemetry_enabled() {
+        return;
+    }
+
     let client = match reqwest::blocking::Client::builder()
         .connect_timeout(CONNECT_TIMEOUT)
         .timeout(REQUEST_TIMEOUT)
@@ -255,3 +287,50 @@ fn send_event_blocking(event: &str, dims: &[(String, String)], client_id: &str)
         .json(&body)
         .send();
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn declined_master_consent_disables_compatibility_reports() {
+        let config = config_for_consent(false);
+
+        assert!(!config.enabled);
+        assert_eq!(config.compatibility_reports, CompatibilityReports::Off);
+    }
+
+    #[test]
+    fn master_opt_out_rejects_even_an_enabled_compatibility_channel() {
+        let config = TelemetryConfig {
+            enabled: false,
+            client_id: "anonymous-id".into(),
+            compatibility_reports: CompatibilityReports::On,
+        };
+
+        assert!(apply_master_consent(Some(config), false).is_none());
+        assert!(apply_master_consent(None, false).is_none());
+    }
+
+    #[test]
+    fn environment_opt_out_overrides_stored_consent() {
+        let config = TelemetryConfig {
+            enabled: true,
+            client_id: "anonymous-id".into(),
+            compatibility_reports: CompatibilityReports::On,
+        };
+
+        let active = apply_master_consent(Some(config.clone()), false)
+            .expect("stored master consent should enable telemetry");
+        assert_eq!(active.compatibility_reports, CompatibilityReports::On);
+        assert!(apply_master_consent(Some(config), true).is_none());
+    }
+
+    #[test]
+    fn accepted_master_consent_keeps_compatibility_reports_opt_in() {
+        let config = config_for_consent(true);
+
+        assert!(config.enabled);
+        assert_eq!(config.compatibility_reports, CompatibilityReports::Ask);
+    }
+}
diff --git a/docs/src/cli/telemetry.md b/docs/src/cli/telemetry.md
index eba96a66c9..c69ac0a497 100644
--- a/docs/src/cli/telemetry.md
+++ b/docs/src/cli/telemetry.md
@@ -1,10 +1,12 @@
 # Privacy & Telemetry
 
-Perry ships **two independent opt-in channels** for sending data home —
-nothing leaves your machine without an explicit `enabled = true` or `on` in
-`~/.perry/config.toml`. Both honour `PERRY_NO_TELEMETRY=1` and `CI=true`.
+Perry sends no telemetry unless you accept the first-run prompt (or explicitly
+set `telemetry.enabled = true` in `~/.perry/config.toml`). This setting is the
+master consent gate for every telemetry channel. If it is false or missing,
+nothing is sent, even when `compatibility_reports = "on"`. The environment
+overrides `PERRY_NO_TELEMETRY=1` and `CI=true` always win as well.
 
-## 1. Generic usage analytics — `telemetry.enabled`
+## 1. Master consent and generic usage analytics — `telemetry.enabled`
 
 Counts `perry compile`, `perry init`, `perry publish` invocations on a
 background HTTP POST. Sends: command name, platform (`darwin`/`linux`/...),
@@ -12,8 +14,9 @@ Perry version, success/error status, and an anonymous client UUID.
 
 ## 2. Compatibility reports — `telemetry.compatibility_reports` (#849)
 
-Separate opt-in for "I hit an unsupported TS/Node feature and bailed." Sends
-a structured report when the compiler emits one of these diagnostic codes:
+Additional opt-in for "I hit an unsupported TS/Node feature and bailed."
+This channel is available only while the master `enabled` consent is true.
+It sends a structured report when the compiler emits one of these diagnostic codes:
 `UnsupportedBinaryOp`, `UnsupportedExpression`, `UnsupportedStatement`,
 `DynamicPropertyAccess`, `ImplicitCoercion`, `UnresolvedImport`, `NoOpStub`.
 
@@ -64,8 +67,8 @@ To opt out at the file level, edit `~/.perry/config.toml`:
 
 ```toml
 [telemetry]
-enabled = false                  # generic analytics off
-compatibility_reports = "off"    # #849 compat reports off
+enabled = false                  # all telemetry off
+compatibility_reports = "off"    # optional; master opt-out already wins
 ```
 
 See also the [`PERRY_NO_TELEMETRY` row in the perry.toml reference](perry-toml.md).