diff --git a/crates/omnigraph-cli/tests/support/mod.rs b/crates/omnigraph-cli/tests/support/mod.rs
index 855d8e0..c30ed28 100644
--- a/crates/omnigraph-cli/tests/support/mod.rs
+++ b/crates/omnigraph-cli/tests/support/mod.rs
@@ -218,6 +218,18 @@ pub fn spawn_server_with_cluster(cluster_dir: &Path) -> TestServer {
     spawn_server_process(command)
 }
 
+/// Cluster boot with the server process's cwd set explicitly — used to prove
+/// rule 0 never touches the cwd omnigraph.yaml search.
+pub fn spawn_server_with_cluster_in(cluster_dir: &Path, cwd: &Path) -> TestServer {
+    let mut command = server_process();
+    command
+        .arg("--cluster")
+        .arg(cluster_dir)
+        .arg("--unauthenticated")
+        .current_dir(cwd);
+    spawn_server_process(command)
+}
+
 pub fn spawn_server_with_cluster_env(cluster_dir: &Path, envs: &[(&str, &str)]) -> TestServer {
     let mut command = server_process();
     command.arg("--cluster").arg(cluster_dir);
diff --git a/crates/omnigraph-cli/tests/system_local.rs b/crates/omnigraph-cli/tests/system_local.rs
index 4b5e4b6..b2afdab 100644
--- a/crates/omnigraph-cli/tests/system_local.rs
+++ b/crates/omnigraph-cli/tests/system_local.rs
@@ -2152,3 +2152,37 @@ policies:
     // unknown query — the server's anti-probing contract.
     assert_eq!(invoke("admin-token").status().as_u16(), 404);
 }
+
+/// Rule 0 (axiom 15): a --cluster server never reads omnigraph.yaml — not
+/// even the implicit cwd search. A MALFORMED config in the process cwd must
+/// not affect boot or serving.
+#[test]
+fn cluster_server_boot_ignores_local_config_in_cwd() {
+    let cluster = tempfile::tempdir().unwrap();
+    std::fs::write(
+        cluster.path().join("people.pg"),
+        "\nnode Person {\n  name: String @key\n}\n",
+    )
+    .unwrap();
+    std::fs::write(
+        cluster.path().join("cluster.yaml"),
+        "version: 1\ngraphs:\n  knowledge:\n    schema: ./people.pg\n",
+    )
+    .unwrap();
+    for command in ["import", "apply"] {
+        let output = cli()
+            .arg("cluster")
+            .arg(command)
+            .arg("--config")
+            .arg(cluster.path())
+            .output()
+            .unwrap();
+        assert!(output.status.success(), "cluster {command} failed");
+    }
+    let cwd = tempfile::tempdir().unwrap();
+    std::fs::write(cwd.path().join("omnigraph.yaml"), "{{{{ not yaml").unwrap();
+
+    let server = spawn_server_with_cluster_in(cluster.path(), cwd.path());
+    let response = reqwest::blocking::get(format!("{}/healthz", server.base_url)).unwrap();
+    assert!(response.status().is_success());
+}