output schema has unnecessary restriction type=object

[spacewander]

Describe the bug
A clear and concise description of what the bug is.

The typescript SDK requires that the outputSchema be in type: "object".

typescript-sdk/src/types.ts

Lines 1013 to 1018 in 0c1cbf0

	outputSchema: z
	.object({
	type: z.literal('object'),
	properties: z.record(z.string(), AssertObjectSchema).optional(),
	required: z.optional(z.array(z.string())),
	additionalProperties: z.optional(z.boolean())

The current constraint prevents describing the response for list and batch requests.
This is noteworthy as the specification does not strictly mandate that the outputSchema must be an object (see: https://modelcontextprotocol.io/specification/draft/server/tools#output-schema).
Consequently, the Python SDK does not enforce this schema constraint on the output.

To Reproduce
Steps to reproduce the behavior:

Let the MCP server return an outputSchema in this format:

         {
            type: "array",
            properties: {
              foo: { type: "string" }
            }
          }

Then an error is thrown:

ZodError: [
  {
    "received": "array",
    "code": "invalid_literal",
    "expected": "object",
    "path": [
      "tools",
      0,
      "outputSchema",
      "type"
    ],
    "message": "Invalid literal value, expected \"object\""
  }
]

Expected behavior
A clear and concise description of what you expected to happen.

Should accept any valid JSONSchema, at least the array one.