fix: start codex on Windows by using shell; keep mcp args parseable (#40)

Windows global installs expose codex as codex.cmd; spawning 'codex' without shell hits ENOENT.

Enable shell to align with Claude's Windows behavior and resolve PATH lookup.

Shell spawn makes cmd.exe strip TOML double quotes in -c arrays, so args become a string.

Switch mcp args to TOML literal (single-quoted) arrays to preserve types; update tests.

cli/src/codex/codexLocal.ts

@@ -80,7 +80,8 @@ export async function codexLocal(opts: {
             spawnName: 'codex',
             installHint: 'Codex CLI',
             includeCause: true,
-            logExit: true
+            logExit: true,
+            shell: process.platform === 'win32'
         });
     } finally {
         process.stdin.resume();

cli/src/codex/utils/codexMcpConfig.test.ts

@@ -15,7 +15,7 @@ describe('codexMcpConfig', () => {
 
             expect(args).toEqual([
                 '-c', 'mcp_servers.hapi.command="hapi"',
-                '-c', 'mcp_servers.hapi.args=["mcp","--url","http://localhost:3000"]'
+                '-c', "mcp_servers.hapi.args=['mcp','--url','http://localhost:3000']"
             ]);
         });
 

cli/src/codex/utils/codexMcpConfig.ts

@@ -20,12 +20,25 @@ function escapeTomlString(value: string): string {
         .replace(/\t/g, '\\t');
 }
 
+/**
+ * Escape a string value for use in a TOML single-quoted literal string.
+ * Only single quotes need escaping (by doubling them).
+ */
+function escapeTomlLiteralString(value: string): string {
+    return value.replace(/'/g, "''");
+}
+
+function buildTomlLiteralArray(values: string[]): string {
+    const items = values.map((value) => `'${escapeTomlLiteralString(value)}'`);
+    return `[${items.join(',')}]`;
+}
+
 /**
  * Build -c arguments for MCP server configuration.
  *
  * Generates arguments like:
  *   -c 'mcp_servers.hapi.command="hapi"'
- *   -c 'mcp_servers.hapi.args=["mcp", "--url", "http://..."]'
+ *   -c 'mcp_servers.hapi.args=['mcp', '--url', 'http://...']'
  *
  * @param mcpServers - Map of server name to server config
  * @returns Array of CLI arguments to pass to codex
@@ -39,9 +52,9 @@ export function buildMcpServerConfigArgs(
         // -c 'mcp_servers.<name>.command="<command>"'
         configArgs.push('-c', `mcp_servers.${name}.command="${escapeTomlString(server.command)}"`);
 
-        // -c 'mcp_servers.<name>.args=["arg1", "arg2"]'
-        // JSON.stringify produces valid TOML array syntax for simple string arrays
-        const argsToml = JSON.stringify(server.args);
+        // -c 'mcp_servers.<name>.args=['arg1','arg2']'
+        // Use TOML literal strings to avoid shell-quote mangling on Windows.
+        const argsToml = buildTomlLiteralArray(server.args);
         configArgs.push('-c', `mcp_servers.${name}.args=${argsToml}`);
     }