initial mcp add interface (#3543)

Adds `codex mcp add`, `codex mcp list`, `codex mcp remove`. Currently writes to global config.

codex-rs/cli/tests/mcp_add_remove.rs

@@ -0,0 +1,86 @@
+use std::path::Path;
+
+use anyhow::Result;
+use codex_core::config::load_global_mcp_servers;
+use predicates::str::contains;
+use pretty_assertions::assert_eq;
+use tempfile::TempDir;
+
+fn codex_command(codex_home: &Path) -> Result<assert_cmd::Command> {
+    let mut cmd = assert_cmd::Command::cargo_bin("codex")?;
+    cmd.env("CODEX_HOME", codex_home);
+    Ok(cmd)
+}
+
+#[test]
+fn add_and_remove_server_updates_global_config() -> Result<()> {
+    let codex_home = TempDir::new()?;
+
+    let mut add_cmd = codex_command(codex_home.path())?;
+    add_cmd
+        .args(["mcp", "add", "docs", "--", "echo", "hello"])
+        .assert()
+        .success()
+        .stdout(contains("Added global MCP server 'docs'."));
+
+    let servers = load_global_mcp_servers(codex_home.path())?;
+    assert_eq!(servers.len(), 1);
+    let docs = servers.get("docs").expect("server should exist");
+    assert_eq!(docs.command, "echo");
+    assert_eq!(docs.args, vec!["hello".to_string()]);
+    assert!(docs.env.is_none());
+
+    let mut remove_cmd = codex_command(codex_home.path())?;
+    remove_cmd
+        .args(["mcp", "remove", "docs"])
+        .assert()
+        .success()
+        .stdout(contains("Removed global MCP server 'docs'."));
+
+    let servers = load_global_mcp_servers(codex_home.path())?;
+    assert!(servers.is_empty());
+
+    let mut remove_again_cmd = codex_command(codex_home.path())?;
+    remove_again_cmd
+        .args(["mcp", "remove", "docs"])
+        .assert()
+        .success()
+        .stdout(contains("No MCP server named 'docs' found."));
+
+    let servers = load_global_mcp_servers(codex_home.path())?;
+    assert!(servers.is_empty());
+
+    Ok(())
+}
+
+#[test]
+fn add_with_env_preserves_key_order_and_values() -> Result<()> {
+    let codex_home = TempDir::new()?;
+
+    let mut add_cmd = codex_command(codex_home.path())?;
+    add_cmd
+        .args([
+            "mcp",
+            "add",
+            "envy",
+            "--env",
+            "FOO=bar",
+            "--env",
+            "ALPHA=beta",
+            "--",
+            "python",
+            "server.py",
+        ])
+        .assert()
+        .success();
+
+    let servers = load_global_mcp_servers(codex_home.path())?;
+    let envy = servers.get("envy").expect("server should exist");
+    let env = envy.env.as_ref().expect("env should be present");
+
+    assert_eq!(env.len(), 2);
+    assert_eq!(env.get("FOO"), Some(&"bar".to_string()));
+    assert_eq!(env.get("ALPHA"), Some(&"beta".to_string()));
+
+    Ok(())
+}

codex-rs/cli/tests/mcp_list.rs

@@ -0,0 +1,106 @@
+use std::path::Path;
+
+use anyhow::Result;
+use predicates::str::contains;
+use pretty_assertions::assert_eq;
+use serde_json::Value as JsonValue;
+use tempfile::TempDir;
+
+fn codex_command(codex_home: &Path) -> Result<assert_cmd::Command> {
+    let mut cmd = assert_cmd::Command::cargo_bin("codex")?;
+    cmd.env("CODEX_HOME", codex_home);
+    Ok(cmd)
+}
+
+#[test]
+fn list_shows_empty_state() -> Result<()> {
+    let codex_home = TempDir::new()?;
+
+    let mut cmd = codex_command(codex_home.path())?;
+    let output = cmd.args(["mcp", "list"]).output()?;
+    assert!(output.status.success());
+    let stdout = String::from_utf8(output.stdout)?;
+    assert!(stdout.contains("No MCP servers configured yet."));
+
+    Ok(())
+}
+
+#[test]
+fn list_and_get_render_expected_output() -> Result<()> {
+    let codex_home = TempDir::new()?;
+
+    let mut add = codex_command(codex_home.path())?;
+    add.args([
+        "mcp",
+        "add",
+        "docs",
+        "--env",
+        "TOKEN=secret",
+        "--",
+        "docs-server",
+        "--port",
+        "4000",
+    ])
+    .assert()
+    .success();
+
+    let mut list_cmd = codex_command(codex_home.path())?;
+    let list_output = list_cmd.args(["mcp", "list"]).output()?;
+    assert!(list_output.status.success());
+    let stdout = String::from_utf8(list_output.stdout)?;
+    assert!(stdout.contains("Name"));
+    assert!(stdout.contains("docs"));
+    assert!(stdout.contains("docs-server"));
+    assert!(stdout.contains("TOKEN=secret"));
+
+    let mut list_json_cmd = codex_command(codex_home.path())?;
+    let json_output = list_json_cmd.args(["mcp", "list", "--json"]).output()?;
+    assert!(json_output.status.success());
+    let stdout = String::from_utf8(json_output.stdout)?;
+    let parsed: JsonValue = serde_json::from_str(&stdout)?;
+    let array = parsed.as_array().expect("expected array");
+    assert_eq!(array.len(), 1);
+    let entry = &array[0];
+    assert_eq!(entry.get("name"), Some(&JsonValue::String("docs".into())));
+    assert_eq!(
+        entry.get("command"),
+        Some(&JsonValue::String("docs-server".into()))
+    );
+
+    let args = entry
+        .get("args")
+        .and_then(|v| v.as_array())
+        .expect("args array");
+    assert_eq!(
+        args,
+        &vec![
+            JsonValue::String("--port".into()),
+            JsonValue::String("4000".into())
+        ]
+    );
+
+    let env = entry
+        .get("env")
+        .and_then(|v| v.as_object())
+        .expect("env map");
+    assert_eq!(env.get("TOKEN"), Some(&JsonValue::String("secret".into())));
+
+    let mut get_cmd = codex_command(codex_home.path())?;
+    let get_output = get_cmd.args(["mcp", "get", "docs"]).output()?;
+    assert!(get_output.status.success());
+    let stdout = String::from_utf8(get_output.stdout)?;
+    assert!(stdout.contains("docs"));
+    assert!(stdout.contains("command: docs-server"));
+    assert!(stdout.contains("args: --port 4000"));
+    assert!(stdout.contains("env: TOKEN=secret"));
+    assert!(stdout.contains("remove: codex mcp remove docs"));
+
+    let mut get_json_cmd = codex_command(codex_home.path())?;
+    get_json_cmd
+        .args(["mcp", "get", "docs", "--json"])
+        .assert()
+        .success()
+        .stdout(contains("\"name\": \"docs\""));
+
+    Ok(())
+}