ENG-8589: Don't log the MCP client secret under --debug

src/commands/claude/__tests__/mcp.test.ts

@@ -8,8 +8,8 @@ This file is part of @p0security/cli
 
 You should have received a copy of the GNU General Public License along with @p0security/cli. If not, see <https://www.gnu.org/licenses/>.
 **/
-import { clientPath, spawnClaude } from "../mcp";
-import { describe, expect, it } from "vitest";
+import { clientPath, provisionServer, spawnClaude } from "../mcp";
+import { describe, expect, it, vi } from "vitest";
 
 // Stands in for the `claude` executable: these exercise the real child
 // process wiring, which is the thing that was broken. Run node rather than a
@@ -41,6 +41,47 @@ describe("clientPath", () => {
   });
 });
 
+describe("MCP client secret debug output", () => {
+  it("reports that the secret is set without logging its value", async () => {
+    const secret = "sentinel-oauth-client-secret";
+    const error = vi.spyOn(console, "error").mockImplementation(() => {});
+    const runClaude = vi.fn().mockResolvedValue(undefined);
+
+    try {
+      await provisionServer(
+        {
+          debug: true,
+          callbackPort: 52566,
+          scope: undefined,
+          server: "server",
+        },
+        {
+          client: {
+            id: "client-id",
+            redirectUri: "http://localhost:52566",
+            secret,
+          },
+          server: { id: "client-id", url: "https://example.com" },
+        },
+        { server: { id: "server-id", url: "https://example.com" } },
+        "claude",
+        runClaude
+      );
+
+      expect(error).toHaveBeenCalledWith("Client secret", "set");
+      expect(error.mock.calls.flat().join(" ")).not.toContain(secret);
+      expect(runClaude).toHaveBeenCalledWith(
+        "claude",
+        expect.any(Array),
+        expect.objectContaining({ MCP_CLIENT_SECRET: secret })
+      );
+      expect(runClaude.mock.calls[0]![1]).not.toContain(secret);
+    } finally {
+      error.mockRestore();
+    }
+  });
+});
+
 describe("spawnClaude", () => {
   it("resolves when claude exits 0", async () => {
     await expect(node("process.exit(0)")).resolves.toBeUndefined();

src/commands/claude/mcp.ts

@@ -222,12 +222,14 @@ const getClaudeFile = async () => {
   }
 };
 
-const provisionServer = async (
+export const provisionServer = async (
   argv: AddMcpServerArgs,
   { client }: CreateMcpClientResp,
-  { server }: GetMcpServerResp
+  { server }: GetMcpServerResp,
+  claudeFileOverride?: string,
+  runClaude: typeof spawnClaude = spawnClaude
 ) => {
-  const claudeFile = await getClaudeFile();
+  const claudeFile = claudeFileOverride ?? (await getClaudeFile());
   assert(client.secret, "No client secret");
   debug(argv, "Server", server);
   // Claude Code's `mcp add-json` doesn't accept oauth fields in its JSON
@@ -254,12 +256,12 @@ const provisionServer = async (
     server.id,
     server.url,
   ];
-  debug(argv, "Client secret", client.secret);
+  debug(argv, "Client secret", "set");
   debug(argv, ["claude", ...args].join(" "));
   // Spread process.env so the spawned `claude` inherits PATH / HOME /
   // NODE_OPTIONS / etc. (`env: { MCP_CLIENT_SECRET }` alone would replace
   // the whole environment).
-  await spawnClaude(claudeFile, args, {
+  await runClaude(claudeFile, args, {
     ...process.env,
     MCP_CLIENT_SECRET: client.secret,
   });