diff --git a/crates/picloud-cli/tests/cli.rs b/crates/picloud-cli/tests/cli.rs
index 612ad9c..3d0d930 100644
--- a/crates/picloud-cli/tests/cli.rs
+++ b/crates/picloud-cli/tests/cli.rs
@@ -23,6 +23,7 @@ mod dead_letters;
 mod email_queue;
 mod enabled;
 mod env_overlay;
+mod group_secrets;
 mod groups;
 mod init;
 mod invoke;
diff --git a/crates/picloud-cli/tests/fixtures/read-secret.rhai b/crates/picloud-cli/tests/fixtures/read-secret.rhai
new file mode 100644
index 0000000..0b2db58
--- /dev/null
+++ b/crates/picloud-cli/tests/fixtures/read-secret.rhai
@@ -0,0 +1,5 @@
+// Phase-3 group-secrets journey fixture: returns the resolved `stripe-key`
+// secret verbatim so the test can assert runtime injection across the group
+// chain (inherited group value) vs an app-owned proximity override. The
+// value is decrypted under the resolved owner's AAD before injection.
+secrets::get("stripe-key")
diff --git a/crates/picloud-cli/tests/group_secrets.rs b/crates/picloud-cli/tests/group_secrets.rs
new file mode 100644
index 0000000..c651cbc
--- /dev/null
+++ b/crates/picloud-cli/tests/group_secrets.rs
@@ -0,0 +1,187 @@
+//! Phase-3 group secrets, end to end via `pic`:
+//!
+//!   1. **Inheritance + proximity** — a group-owned secret is injected into a
+//!      descendant app's script via `secrets::get` (decrypted under the
+//!      group AAD), and an app-owned secret of the same name shadows it
+//!      (decrypted under the app AAD). Exercises the resolver + the dual
+//!      owner-AAD open path against real Postgres.
+//!   2. **Masked-read boundary** — a `group_admin` reads the secret VALUE,
+//!      an app-only dev is denied the value (403) yet still sees the secret
+//!      EXISTS (masked) in `config/effective`. That is the headline §5.3
+//!      property: an app runs with config its own devs cannot read.
+
+use predicates::prelude::*;
+
+use crate::common;
+use crate::common::cleanup::{AppGuard, GroupGuard};
+use crate::common::member;
+
+#[ignore = "needs DATABASE_URL pointing at a running Postgres"]
+#[test]
+fn group_secret_is_injected_then_app_value_overrides() {
+    let Some(fx) = common::fixture_or_skip() else {
+        return;
+    };
+    let env = common::admin_env(fx);
+    let acme = common::unique_slug("gs-acme");
+    let app = common::unique_slug("gs-app");
+
+    // Group `acme` with a `stripe-key` group secret (value via stdin).
+    let _g_acme = GroupGuard::new(&env.url, &env.token, &acme);
+    common::pic_as(&env)
+        .args(["groups", "create", &acme])
+        .assert()
+        .success();
+    common::pic_as(&env)
+        .args(["secrets", "set", "--group", &acme, "stripe-key"])
+        .write_stdin("sk_group")
+        .assert()
+        .success();
+
+    // App under acme with a script that reads + returns the resolved secret.
+    let _app = AppGuard::new(&env.url, &env.token, &app);
+    common::pic_as(&env)
+        .args(["apps", "create", &app, "--group", &acme])
+        .assert()
+        .success();
+    let fixture = common::fixture_path("read-secret.rhai");
+    common::pic_as(&env)
+        .args([
+            "scripts",
+            "deploy",
+            fixture.to_str().unwrap(),
+            "--app",
+            &app,
+        ])
+        .assert()
+        .success();
+    let ls = common::pic_as(&env)
+        .args(["scripts", "ls", "--app", &app])
+        .output()
+        .expect("scripts ls");
+    let id = common::parse_first_id(std::str::from_utf8(&ls.stdout).unwrap())
+        .expect("scripts ls should produce one row");
+
+    // Inherited: the app has no own `stripe-key`, so the group's value is
+    // injected (decrypted under the GROUP AAD).
+    assert_eq!(
+        invoke_body(&env, &id),
+        serde_json::json!("sk_group"),
+        "inherited group secret"
+    );
+
+    // Proximity override: an app-owned `stripe-key` shadows the group value
+    // (decrypted under the APP AAD — proving both AAD namespaces open).
+    common::pic_as(&env)
+        .args(["secrets", "set", "--app", &app, "stripe-key"])
+        .write_stdin("sk_app")
+        .assert()
+        .success();
+    assert_eq!(
+        invoke_body(&env, &id),
+        serde_json::json!("sk_app"),
+        "app override"
+    );
+}
+
+#[ignore = "needs DATABASE_URL pointing at a running Postgres"]
+#[test]
+fn group_secret_value_is_masked_from_app_devs() {
+    let Some(fx) = common::fixture_or_skip() else {
+        return;
+    };
+    let env = common::admin_env(fx);
+    let acme = common::unique_slug("gsm-acme");
+    let app = common::unique_slug("gsm-app");
+
+    let _g_acme = GroupGuard::new(&env.url, &env.token, &acme);
+    common::pic_as(&env)
+        .args(["groups", "create", &acme])
+        .assert()
+        .success();
+    common::pic_as(&env)
+        .args(["secrets", "set", "--group", &acme, "stripe-key"])
+        .write_stdin("sk_live_masked")
+        .assert()
+        .success();
+    let _app = AppGuard::new(&env.url, &env.token, &app);
+    common::pic_as(&env)
+        .args(["apps", "create", &app, "--group", &acme])
+        .assert()
+        .success();
+
+    // An app dev: a Member granted `editor` on the app, but NO group role.
+    let dev = member::member_user(fx, &common::unique_username("appdev"));
+    let dev_env = common::custom_env(&fx.url, &dev.token);
+    common::seed_credentials(&dev_env, &dev.username);
+    member::grant_membership(fx, &app, &dev.id, "editor");
+
+    // Denied the VALUE: the value endpoint is gated GroupSecretsRead at the
+    // owning group, which the app dev does not hold.
+    common::pic_as(&dev_env)
+        .args(["secrets", "read", "--group", &acme, "stripe-key"])
+        .assert()
+        .failure()
+        .stderr(predicate::str::contains("HTTP 403"));
+
+    // But the dev DOES see it EXISTS (masked) in the app's effective config —
+    // status `set`, owner group, never the value. Asserted directly against
+    // the endpoint to avoid the CLI's manifest requirement.
+    let effective = reqwest::blocking::Client::new()
+        .get(format!(
+            "{}/api/v1/admin/apps/{}/config/effective",
+            fx.url, app
+        ))
+        .bearer_auth(&dev.token)
+        .send()
+        .expect("config effective");
+    assert!(
+        effective.status().is_success(),
+        "dev can read effective config"
+    );
+    let body: serde_json::Value = effective.json().expect("effective json");
+    let masked = &body["secrets"]["stripe-key"];
+    assert_eq!(masked["status"], "set", "secret shown as set");
+    assert_eq!(masked["owner"]["kind"], "group", "owned by the group");
+    assert!(
+        masked.get("value").is_none(),
+        "value must never appear in effective config: {masked}"
+    );
+
+    // A group_admin CAN read the value.
+    let gadmin = member::member_user(fx, &common::unique_username("gadmin"));
+    let gadmin_env = common::custom_env(&fx.url, &gadmin.token);
+    common::seed_credentials(&gadmin_env, &gadmin.username);
+    common::pic_as(&env)
+        .args([
+            "groups",
+            "members",
+            "add",
+            &acme,
+            &gadmin.id,
+            "--role",
+            "app_admin",
+        ])
+        .assert()
+        .success();
+    common::pic_as(&gadmin_env)
+        .args(["secrets", "read", "--group", &acme, "stripe-key"])
+        .assert()
+        .success()
+        .stdout(predicate::str::contains("sk_live_masked"));
+}
+
+/// Invoke a script via `pic scripts invoke <id>` (→ `/api/v1/execute/{id}`)
+/// and parse its JSON body.
+fn invoke_body(env: &common::TestEnv, id: &str) -> serde_json::Value {
+    let out = common::pic_as(env)
+        .args(["scripts", "invoke", id])
+        .output()
+        .expect("scripts invoke");
+    assert!(
+        out.status.success(),
+        "invoke failed: {}",
+        String::from_utf8_lossy(&out.stderr)
+    );
+    serde_json::from_slice(&out.stdout).expect("invoke body is JSON")
+}
diff --git a/crates/picloud-cli/tests/secrets.rs b/crates/picloud-cli/tests/secrets.rs
index 6e93470..157ce35 100644
--- a/crates/picloud-cli/tests/secrets.rs
+++ b/crates/picloud-cli/tests/secrets.rs
@@ -35,7 +35,7 @@ fn set_ls_rm_round_trip() {
         .expect("secrets ls");
     let stdout = String::from_utf8(out.stdout).unwrap();
     let header = stdout.lines().next().expect("header");
-    assert_eq!(common::cells(header), vec!["name", "updated_at"]);
+    assert_eq!(common::cells(header), vec!["name", "env", "updated_at"]);
     assert!(
         stdout.lines().skip(1).any(|l| l.starts_with("api_key")),
         "api_key missing from ls: {stdout}"