From 9edc44c17780977a20508c49e80477a91ec892c0 Mon Sep 17 00:00:00 2001
From: rowkav09 <rowkav0809@highgateschool.org.uk>
Date: Mon, 5 Oct 2026 08:03:18 +0100
Subject: [PATCH] fix: retain simultaneous primitive composition constraints

I preserve both anyOf and oneOf when they appear together on a primitive
parameter schema instead of silently choosing oneOf and dropping anyOf.

I added fail-first validation regressions for all parameter locations.
---
 src/manifest.ts                         | 28 ++++++++++++++-----------
 test/parameter-composition-root.test.ts | 16 ++++++++++++++
 2 files changed, 32 insertions(+), 12 deletions(-)

diff --git a/src/manifest.ts b/src/manifest.ts
index d362c25..e05565e 100644
--- a/src/manifest.ts
+++ b/src/manifest.ts
@@ -160,21 +160,25 @@ const JSON_TYPES = new Set(['string', 'number', 'integer', 'boolean', 'array', '
  * compositions from the loaded parameter schema when Forge narrows them. */
 function primitiveComposition(schema: Record<string, unknown> | undefined): Record<string, unknown> | undefined {
   if (!schema) return undefined;
-  const key = Array.isArray(schema.oneOf) ? 'oneOf' : Array.isArray(schema.anyOf) ? 'anyOf' : undefined;
-  if (!key) return undefined;
-  const branches = schema[key] as unknown[];
-  if (branches.length === 0) return undefined;
-  const mapped = branches.map((branch) => {
-    const node = resolveDocRef(branch) as Record<string, unknown> | undefined;
-    if (!node || typeof node.type !== 'string' || !['string', 'number', 'integer', 'boolean', 'null'].includes(node.type)) return undefined;
-    const { $ref: _ref, nullable: _nullable, xml: _xml, ...constraints } = node;
-    return constraints;
-  });
-  if (mapped.some((branch) => branch === undefined)) return undefined;
+  const keys = ['anyOf', 'oneOf'].filter(key => Array.isArray(schema[key]));
+  if (keys.length === 0) return undefined;
+  const compositions: Record<string, unknown> = {};
+  for (const key of keys) {
+    const branches = schema[key] as unknown[];
+    if (branches.length === 0) return undefined;
+    const mapped = branches.map((branch) => {
+      const node = resolveDocRef(branch) as Record<string, unknown> | undefined;
+      if (!node || typeof node.type !== 'string' || !['string', 'number', 'integer', 'boolean', 'null'].includes(node.type)) return undefined;
+      const { $ref: _ref, nullable: _nullable, xml: _xml, ...constraints } = node;
+      return constraints;
+    });
+    if (mapped.some((branch) => branch === undefined)) return undefined;
+    compositions[key] = mapped;
+  }
   return {
     ...(typeof schema.type === 'string' ? { type: schema.type } : {}),
     ...(Array.isArray(schema.enum) ? { enum: schema.enum } : {}),
-    [key]: mapped,
+    ...compositions,
   };
 }
 
diff --git a/test/parameter-composition-root.test.ts b/test/parameter-composition-root.test.ts
index 513465f..d8328c9 100644
--- a/test/parameter-composition-root.test.ts
+++ b/test/parameter-composition-root.test.ts
@@ -26,3 +26,19 @@ for (const location of ['path', 'query', 'header', 'cookie']) {
     assert.equal(validate({ ...args, [arg.name]: 'safe' }), false);
   });
 }
+
+for (const location of ['path', 'query', 'header', 'cookie']) {
+  test(`primitive ${location} parameters retain simultaneous anyOf and oneOf`, async () => {
+    const doc = { openapi: '3.1.0', info: { title: 'Intersections', version: '1' }, components: { schemas: {} },
+      paths: { [location === 'path' ? '/x/{v}' : '/x']: { get: { operationId: 'x', parameters: [{ name: 'v', in: location, required: true, schema: {
+        anyOf: [{ type: 'integer', minimum: 5 }], oneOf: [{ type: 'integer' }, { type: 'string' }],
+      } }], responses: { '200': { description: 'OK' } } } } },
+    } as unknown as OpenAPIV3.Document;
+    await init(doc);
+    const tool = buildManifest(doc).tools[0]!;
+    const validate = compileOutputValidator(JSON.parse(JSON.stringify(tool.inputSchema)));
+    assert.equal(validate({ v: 5 }), true);
+    assert.equal(validate({ v: 4 }), false);
+    assert.equal(validate({ v: 'safe' }), false);
+  });
+}