codex: add enableMcpIntegration option

Work with the shared mcp module for integration and transformation.

Signed-off-by: Austin Horstman <khaneliman12@gmail.com>

tests/modules/programs/codex/default.nix

@@ -6,6 +6,8 @@
   codex-custom-instructions = ./custom-instructions.nix;
   codex-custom-instructions-prefer-xdg-directories = ./custom-instructions-prefer-xdg-directories.nix;
   codex-empty-custom-instructions = ./empty-custom-instructions.nix;
+  codex-mcp-integration = ./mcp-integration.nix;
+  codex-mcp-integration-with-override = ./mcp-integration-with-override.nix;
   codex-skills-inline = ./skills-inline.nix;
   codex-skills-dir = ./skills-dir.nix;
   codex-skills-path-not-directory = ./skills-path-not-directory.nix;

tests/modules/programs/codex/mcp-integration-with-override.nix

@@ -0,0 +1,49 @@
+{
+  programs.mcp = {
+    enable = true;
+    servers = {
+      everything = {
+        command = "npx";
+        args = [
+          "-y"
+          "@modelcontextprotocol/server-everything"
+        ];
+      };
+      context7 = {
+        url = "https://mcp.context7.com/mcp";
+        headers = {
+          CONTEXT7_API_KEY = "{env:CONTEXT7_API_KEY}";
+        };
+      };
+    };
+  };
+
+  programs.codex = {
+    enable = true;
+    enableMcpIntegration = true;
+    settings = {
+      model = "gpt-5-codex";
+      mcp_servers = {
+        custom-server = {
+          url = "http://localhost:3000/mcp";
+          enabled = true;
+          enabled_tools = [
+            "open"
+            "screenshot"
+          ];
+        };
+        everything = {
+          command = "final-command";
+          enabled = false;
+          tool_timeout_sec = 45;
+        };
+      };
+    };
+  };
+
+  nmt.script = ''
+    assertFileExists home-files/.codex/config.toml
+    assertFileContent home-files/.codex/config.toml \
+      ${./mcp-integration-with-override.toml}
+  '';
+}

tests/modules/programs/codex/mcp-integration-with-override.toml

@@ -0,0 +1,18 @@
+model = "gpt-5-codex"
+
+[mcp_servers.context7]
+enabled = true
+url = "https://mcp.context7.com/mcp"
+
+[mcp_servers.context7.http_headers]
+CONTEXT7_API_KEY = "{env:CONTEXT7_API_KEY}"
+
+[mcp_servers.custom-server]
+enabled = true
+enabled_tools = ["open", "screenshot"]
+url = "http://localhost:3000/mcp"
+
+[mcp_servers.everything]
+command = "final-command"
+enabled = false
+tool_timeout_sec = 45

tests/modules/programs/codex/mcp-integration.nix

@@ -0,0 +1,36 @@
+{
+  programs.mcp = {
+    enable = true;
+    servers = {
+      everything = {
+        command = "npx";
+        args = [
+          "-y"
+          "@modelcontextprotocol/server-everything"
+        ];
+      };
+      context7 = {
+        url = "https://mcp.context7.com/mcp";
+        headers = {
+          CONTEXT7_API_KEY = "{env:CONTEXT7_API_KEY}";
+        };
+      };
+      disabled-server = {
+        command = "echo";
+        args = [ "test" ];
+        disabled = true;
+      };
+    };
+  };
+
+  programs.codex = {
+    enable = true;
+    enableMcpIntegration = true;
+  };
+
+  nmt.script = ''
+    assertFileExists home-files/.codex/config.toml
+    assertFileContent home-files/.codex/config.toml \
+      ${./mcp-integration.toml}
+  '';
+}

tests/modules/programs/codex/mcp-integration.toml

@@ -0,0 +1,16 @@
+[mcp_servers.context7]
+enabled = true
+url = "https://mcp.context7.com/mcp"
+
+[mcp_servers.context7.http_headers]
+CONTEXT7_API_KEY = "{env:CONTEXT7_API_KEY}"
+
+[mcp_servers.disabled-server]
+args = ["test"]
+command = "echo"
+enabled = false
+
+[mcp_servers.everything]
+args = ["-y", "@modelcontextprotocol/server-everything"]
+command = "npx"
+enabled = true