Address MCP config filtering review comments

Author: i1bro

src/CodexAcpClient.ts

@@ -720,8 +720,7 @@ function formatUriAsLink(name: string | null | undefined, uri: string): string {
 
 function shouldDeduplicateMcpConflicts(): boolean {
     const disabledByEnv = process.env["DISABLE_MCP_CONFIG_FILTERING"] === "true";
-    const disabledByArg = process.argv.includes("--disable-mcp-config-filtering");
-    return !disabledByEnv && !disabledByArg;
+    return !disabledByEnv;
 }
 
 interface GatewayConfig {

src/__tests__/CodexACPAgent/CodexAcpClient.test.ts

@@ -328,58 +328,6 @@ describe('ACP server test', { timeout: 40_000 }, () => {
         });
     });
 
-    it('passes conflicting ACP MCP servers through when config filtering is disabled', async () => {
-        vi.stubEnv("DISABLE_MCP_CONFIG_FILTERING", "true");
-        try {
-            const mockFixture = createCodexMockTestFixture();
-            const codexAcpClient = mockFixture.getCodexAcpClient();
-            const codexAppServerClient = mockFixture.getCodexAppServerClient();
-
-            vi.spyOn(codexAppServerClient, "listSkills").mockResolvedValue({data: []});
-            const configReadSpy = vi.spyOn(codexAppServerClient, "configRead").mockResolvedValue({
-                config: {
-                    mcp_servers: {
-                        shared_mcp: {
-                            url: "https://example.com/mcp",
-                        },
-                    },
-                },
-            } as any);
-            const threadStartSpy = vi.spyOn(codexAppServerClient, "threadStart").mockResolvedValue({
-                thread: {id: "thread-id"} as any,
-                model: "gpt-5",
-                reasoningEffort: "medium",
-                serviceTier: null,
-            } as any);
-            vi.spyOn(codexAppServerClient, "listModels").mockResolvedValue({
-                data: [createTestModel({id: "gpt-5"})],
-                nextCursor: null,
-            });
-
-            await codexAcpClient.newSession({
-                cwd: "/workspace",
-                mcpServers: [{
-                    name: "shared mcp",
-                    command: "npx",
-                    args: ["shared"],
-                    env: [],
-                }],
-            });
-
-            const threadStartRequest = threadStartSpy.mock.calls[0]![0];
-            expect(configReadSpy).not.toHaveBeenCalled();
-            expect(threadStartRequest.config?.["mcp_servers"]).toEqual({
-                shared_mcp: {
-                    command: "npx",
-                    args: ["shared"],
-                    env: {},
-                },
-            });
-        } finally {
-            vi.unstubAllEnvs();
-        }
-    });
-
     it('waits for typed mcp startup status updates and returns terminal states', async () => {
         const mockFixture = createCodexMockTestFixture();
         const codexAcpClient = mockFixture.getCodexAcpClient();

src/__tests__/CodexACPAgent/mcp-config-merge.test.ts

@@ -35,6 +35,7 @@ url = "https://example.com/mcp"
     });
 
     afterEach(() => {
+        vi.unstubAllEnvs();
         removeDirectoryWithRetry(codexHome);
     });
 
@@ -66,4 +67,40 @@ url = "https://example.com/mcp"
         expect(transportDump).contain("Configured MCP servers:");
         expect(transportDump).contain("- shared-mcp");
     });
+
+    it('should pass the conflicting ACP MCP through when config filtering is disabled', async () => {
+        vi.stubEnv("DISABLE_MCP_CONFIG_FILTERING", "true");
+        const codexAcpAgent = fixture.getCodexAcpAgent();
+        await codexAcpAgent.initialize({protocolVersion: 1});
+
+        fixture.getCodexAcpClient().authRequired = vi.fn().mockResolvedValue(false);
+
+        const conflictingMcp: McpServerStdio = {
+            name: "shared-mcp",
+            command: "./node_modules/.bin/mcp-hello-world",
+            args: ["example"],
+            env: [{name: "example", value: "example"}],
+        };
+
+        await codexAcpAgent.newSession({
+            cwd: "",
+            mcpServers: [conflictingMcp],
+        });
+
+        const threadStartRequest = fixture.getCodexConnectionEvents([])
+            .find(event => event.eventType === "request" && event.method === "thread/start");
+        expect(threadStartRequest).toMatchObject({
+            params: {
+                config: {
+                    mcp_servers: {
+                        "shared-mcp": {
+                            command: "./node_modules/.bin/mcp-hello-world",
+                            args: ["example"],
+                            env: {example: "example"},
+                        },
+                    },
+                },
+            },
+        });
+    });
 });