fix(codex): normalize output schemas for OpenAI Structured Outputs compliance

OpenAI's Structured Outputs API requires `additionalProperties: false`
on every object node and `required` to list ALL property keys. Claude
doesn't enforce either, so workflow authors writing provider-agnostic
YAML typically omit both — causing 400 errors when switching to the
Codex provider.

Add `normalizeSchemaForOpenAI()` in the Codex provider that recursively
walks the schema tree and fills in the missing constraints before passing
to the SDK. This makes all existing workflows work with Codex without
any YAML changes.

Fixes the `invalid_json_schema` error on `output_format` nodes when
using `provider: codex` in workflow definitions.

Co-authored-by: Cursor <cursoragent@cursor.com>

Author: Brant Levinson

packages/providers/src/codex/provider.test.ts

@@ -682,7 +682,13 @@ describe('CodexProvider', () => {
 
       expect(mockRunStreamed).toHaveBeenCalledWith(
         'test prompt',
-        expect.objectContaining({ outputSchema: schema })
+        expect.objectContaining({
+          outputSchema: {
+            ...schema,
+            additionalProperties: false,
+            required: ['summary'],
+          },
+        })
       );
     });
 

packages/providers/src/codex/provider.ts

@@ -267,6 +267,50 @@ function extractUsageFromCodexEvent(event: TurnCompletedEvent): TokenUsage {
   };
 }
 
+// ─── Schema Normalizer (OpenAI Structured Outputs compliance) ────────────
+
+/**
+ * Recursively normalize a JSON schema for OpenAI Structured Outputs compliance.
+ *
+ * OpenAI requires two things Claude doesn't:
+ *   1. Every object must have `additionalProperties: false`.
+ *   2. Every object must have a `required` array listing ALL property keys.
+ *
+ * Workflow authors writing provider-agnostic YAML typically omit both.
+ */
+function normalizeSchemaForOpenAI(schema: Record<string, unknown>): Record<string, unknown> {
+  const out = { ...schema };
+
+  if (out.type === 'object') {
+    if (!('additionalProperties' in out)) {
+      out.additionalProperties = false;
+    }
+    if (typeof out.properties === 'object' && out.properties !== null) {
+      const props = out.properties as Record<string, Record<string, unknown>>;
+      const propKeys = Object.keys(props);
+
+      const existingRequired = Array.isArray(out.required) ? (out.required as string[]) : [];
+      const missingRequired = propKeys.filter(k => !existingRequired.includes(k));
+      if (missingRequired.length > 0) {
+        out.required = [...existingRequired, ...missingRequired];
+      }
+
+      const normalized: Record<string, Record<string, unknown>> = {};
+      for (const [key, value] of Object.entries(props)) {
+        normalized[key] =
+          typeof value === 'object' && value !== null ? normalizeSchemaForOpenAI(value) : value;
+      }
+      out.properties = normalized;
+    }
+  }
+
+  if (out.type === 'array' && typeof out.items === 'object' && out.items !== null) {
+    out.items = normalizeSchemaForOpenAI(out.items as Record<string, unknown>);
+  }
+
+  return out;
+}
+
 // ─── Turn Options Builder ────────────────────────────────────────────────
 
 /**
@@ -282,10 +326,10 @@ function buildTurnOptions(requestOptions?: SendQueryOptions): {
     requestOptions?.outputFormat ?? requestOptions?.nodeConfig?.output_format
   );
   if (requestOptions?.outputFormat) {
-    turnOptions.outputSchema = requestOptions.outputFormat.schema;
+    turnOptions.outputSchema = normalizeSchemaForOpenAI(requestOptions.outputFormat.schema);
   }
   if (requestOptions?.nodeConfig?.output_format && !requestOptions?.outputFormat) {
-    turnOptions.outputSchema = requestOptions.nodeConfig.output_format;
+    turnOptions.outputSchema = normalizeSchemaForOpenAI(requestOptions.nodeConfig.output_format);
   }
   if (requestOptions?.abortSignal) {
     turnOptions.signal = requestOptions.abortSignal;