diff --git a/extensions/qa-matrix/src/runners/contract/scenario-runtime-e2ee.ts b/extensions/qa-matrix/src/runners/contract/scenario-runtime-e2ee.ts
index ce552fc9c88..d36bad1e646 100644
--- a/extensions/qa-matrix/src/runners/contract/scenario-runtime-e2ee.ts
+++ b/extensions/qa-matrix/src/runners/contract/scenario-runtime-e2ee.ts
@@ -1,5 +1,5 @@
 import { randomUUID } from "node:crypto";
-import { chmod, mkdir, mkdtemp, rm, writeFile } from "node:fs/promises";
+import { chmod, mkdir, mkdtemp, rm, stat, writeFile } from "node:fs/promises";
 import { tmpdir } from "node:os";
 import path from "node:path";
 import { setTimeout as sleep } from "node:timers/promises";
@@ -315,6 +315,16 @@ async function writeMatrixQaCliOutputArtifacts(params: {
   return { stderrPath, stdoutPath };
 }
 
+async function assertMatrixQaPrivatePathMode(pathToCheck: string, label: string) {
+  if (process.platform === "win32") {
+    return;
+  }
+  const mode = (await stat(pathToCheck)).mode & 0o777;
+  if ((mode & 0o077) !== 0) {
+    throw new Error(`${label} permissions are too broad: ${mode.toString(8)}`);
+  }
+}
+
 function assertMatrixQaCliSasMatches(params: {
   cliSas: ReturnType<typeof parseMatrixQaCliSasText>;
   owner: MatrixVerificationSummary;
@@ -390,10 +400,13 @@ async function createMatrixQaCliSelfVerificationRuntime(params: {
   const stateDir = path.join(rootDir, "state");
   const configPath = path.join(rootDir, "config.json");
   await chmod(rootDir, 0o700).catch(() => undefined);
+  await assertMatrixQaPrivatePathMode(rootDir, "Matrix QA CLI temp directory");
   await mkdir(artifactDir, { mode: 0o700, recursive: true });
   await chmod(artifactDir, 0o700).catch(() => undefined);
+  await assertMatrixQaPrivatePathMode(artifactDir, "Matrix QA CLI artifact directory");
   await mkdir(stateDir, { mode: 0o700, recursive: true });
   await chmod(stateDir, 0o700).catch(() => undefined);
+  await assertMatrixQaPrivatePathMode(stateDir, "Matrix QA CLI state directory");
   await writeFile(
     configPath,
     `${JSON.stringify(
@@ -422,8 +435,9 @@ async function createMatrixQaCliSelfVerificationRuntime(params: {
       null,
       2,
     )}\n`,
-    { mode: 0o600 },
+    { flag: "wx", mode: 0o600 },
   );
+  await assertMatrixQaPrivatePathMode(configPath, "Matrix QA CLI config file");
   const env = {
     ...requireMatrixQaCliRuntimeEnv(params.context),
     FORCE_COLOR: "0",
diff --git a/src/logging/redact.ts b/src/logging/redact.ts
index 3689fb6a4a4..bd27a23beed 100644
--- a/src/logging/redact.ts
+++ b/src/logging/redact.ts
@@ -15,9 +15,11 @@ const DEFAULT_REDACT_KEEP_END = 4;
 
 const DEFAULT_REDACT_PATTERNS: string[] = [
   // ENV-style assignments.
-  String.raw`\b[A-Z0-9_]*(?:KEY|TOKEN|SECRET|PASSWORD|PASSWD)\b\s*[=:]\s*(["']?)([^\s"'\\]+)\1`,
+  String.raw`(?:^|\s)\b[A-Z0-9_]*(?:KEY|TOKEN|SECRET|PASSWORD|PASSWD)\b\s*[=:]\s*(["']?)([^\s"'\\]+)\1`,
   // JSON fields.
   String.raw`"(?:apiKey|token|secret|password|passwd|accessToken|refreshToken|access_token|refresh_token)"\s*:\s*"([^"]+)"`,
+  // URL query parameters.
+  String.raw`([?&](?:access_token|refresh_token)=)([^&#\s]+)`,
   // CLI flags.
   String.raw`--(?:api[-_]?key|hook[-_]?token|token|secret|password|passwd)\s+(["']?)([^\s"']+)\1`,
   // Authorization headers.